U.S. patent application number 16/353639 was filed with the patent office on 2019-07-04 for processes for producing hydrocarbon products.
This patent application is currently assigned to Commonwealth Scientific and Industrial Research Organisation. The applicant listed for this patent is Commonwealth Scientific and Industrial Research Organisation. Invention is credited to Anna El Tahchy, Qing Liu, James Robertson Petrie, Surinder Pal Singh, Thomas Vanhercke.
Application Number | 20190203125 16/353639 |
Document ID | / |
Family ID | 48654931 |
Filed Date | 2019-07-04 |
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United States Patent
Application |
20190203125 |
Kind Code |
A1 |
Vanhercke; Thomas ; et
al. |
July 4, 2019 |
PROCESSES FOR PRODUCING HYDROCARBON PRODUCTS
Abstract
The present invention relates to processes for producing
industrial products such as hydrocarbon products from non-polar
lipids in a vegetative plant part. Preferred industrial products
include alkyl esters which may be blended with petroleum based
fuels.
Inventors: |
Vanhercke; Thomas; (Kaleen,
AU) ; Petrie; James Robertson; (Goulburn, AU)
; El Tahchy; Anna; (Moncrieff, AU) ; Singh;
Surinder Pal; (Downer, AU) ; Liu; Qing;
(Giralang, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Commonwealth Scientific and Industrial Research
Organisation |
Acton |
|
AU |
|
|
Assignee: |
Commonwealth Scientific and
Industrial Research Organisation
Acton
AU
|
Family ID: |
48654931 |
Appl. No.: |
16/353639 |
Filed: |
March 14, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15332654 |
Oct 24, 2016 |
10246641 |
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16353639 |
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14729754 |
Jun 3, 2015 |
9512438 |
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15332654 |
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14283728 |
May 21, 2014 |
9061992 |
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14729754 |
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13725404 |
Dec 21, 2012 |
8735111 |
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14283728 |
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61718563 |
Oct 25, 2012 |
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61580590 |
Dec 27, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C01B 3/22 20130101; C10L
2200/0469 20130101; C10L 1/026 20130101; C11B 1/00 20130101; C11B
1/10 20130101; Y02E 50/32 20130101; C07C 67/48 20130101; C10L
2290/04 20130101; C12N 15/8247 20130101; C10L 2200/0492 20130101;
C11B 7/0075 20130101; C10B 53/02 20130101; C10J 2300/1659 20130101;
Y02E 50/14 20130101; C10L 2290/28 20130101; C10J 2300/0916
20130101; C10L 2270/026 20130101; C11B 3/001 20130101; C10L
2290/544 20130101; Y02E 20/18 20130101; C10L 2200/0476 20130101;
C10L 1/02 20130101; C11B 3/10 20130101; C10J 2300/0906 20130101;
C10L 2290/30 20130101; C01B 32/40 20170801; C10L 2290/06 20130101;
Y02E 50/10 20130101; Y02E 50/30 20130101; C10L 5/44 20130101; C10J
3/82 20130101; C11B 3/14 20130101; C11C 3/003 20130101; C01B
2203/1211 20130101; Y02E 20/16 20130101; Y02E 50/343 20130101; C10L
2290/02 20130101; C10L 2290/42 20130101; C12P 7/6463 20130101; C12Y
204/01101 20130101; C10J 2300/1846 20130101; Y02E 50/13 20130101;
C12N 9/1051 20130101; C12N 15/8218 20130101; C10G 2/00 20130101;
C10G 2/30 20130101; C10L 2290/26 20130101; C11B 3/006 20130101;
Y02E 50/17 20130101; C07K 14/415 20130101 |
International
Class: |
C10B 53/02 20060101
C10B053/02; C10L 5/44 20060101 C10L005/44; C10G 2/00 20060101
C10G002/00; C10L 1/02 20060101 C10L001/02; C07K 14/415 20060101
C07K014/415; C12N 15/82 20060101 C12N015/82; C11B 1/10 20060101
C11B001/10; C11B 3/00 20060101 C11B003/00; C11B 3/10 20060101
C11B003/10; C11B 3/14 20060101 C11B003/14; C11B 7/00 20060101
C11B007/00; C11C 3/00 20060101 C11C003/00; C12N 9/10 20060101
C12N009/10; C10J 3/82 20060101 C10J003/82; C11B 1/00 20060101
C11B001/00; C07C 67/48 20060101 C07C067/48; C01B 3/22 20060101
C01B003/22; C01B 32/40 20060101 C01B032/40; C12P 7/64 20060101
C12P007/64 |
Claims
1. A process for producing an industrial product, the process
comprising the steps of: i) obtaining a vegetative plant part
having a total non-polar lipid content of at least 10% (w/w dry
weight), ii) either a) converting at least some of the lipid in the
vegetative plant part of step i) to the industrial product by
applying heat, chemical, or enzymatic means, or any combination
thereof, to the lipid in situ in the vegetative plant part, or b)
physically processing the vegetative plant part of step i), and
subsequently or simultaneously converting at least some of the
lipid in the processed vegetative plant part to the industrial
product by applying heat, chemical, or enzymatic means, or any
combination thereof, to the lipid in the processed vegetative plant
part, and iii) recovering the industrial product, thereby producing
the industrial product.
2. The process of claim 1, wherein the step of physically
processing the vegetative plant part comprises one or more of
rolling, pressing, crushing or grinding the vegetative plant
part.
3. The process of claim 1, which prior to step ii) further
comprises the steps of: (a) extracting at least some of the
non-polar lipid content from the vegetative plant part as non-polar
lipid, and (b) recovering the extracted non-polar lipid.
4. The process of claim 3, wherein (i) the extracted non-polar
lipid comprises triacylglycerols, wherein the triacylglycerols
comprise at least 90% (w/w) of the extracted non-polar lipid,
and/or (ii) the extracted non-polar lipid comprises free sterols,
steroyl esters, steroyl glycosides, waxes or wax esters, or any
combination thereof.
5. The process of claim 3, wherein step (a) uses an organic
solvent.
6. The process of claim 3 which comprises one or more of a)
recovering the extracted non-polar lipid by collecting it in a
container, b) one or more of degumming, deodorising, decolourising,
drying or fractionating the extracted non-polar lipid, c) removing
at least some waxes and/or wax esters from the extracted non-polar
lipid, and d) analysing the fatty acid composition of the extracted
non-polar lipid.
7. The process of claim 3 in which the volume of the extracted
non-polar lipid is at least 1 litre.
8. The process of claim 1, wherein the industrial product is a
hydrocarbon product such as fatty acid esters, preferably fatty
acid methyl esters and/or a fatty acid ethyl esters, an alkane such
as methane, ethane or a longer-chain alkane, a mixture of longer
chain alkanes, an alkene, a biofuel, carbon monoxide and/or
hydrogen gas, a bioalcohol such as ethanol, propanol, or butanol,
biochar, or a combination of carbon monoxide, hydrogen and
biochar.
9. The process of claim 1, wherein the vegetative plant part is an
aerial plant part or a green plant part.
10. The process of claim 9, wherein the vegetative plant part is a
plant leaf or stem.
11. The process of claim 1, further comprising a step of harvesting
the vegetative plant part from a plant with a mechanical
harvester.
12. The process of claim 11, wherein the vegetative plant part is
harvested from the plant some time between about the time of
flowering of the plant to about the time senescence of the plant
has started.
13. The process of claim 1, wherein the vegetative plant part
comprises a total non-polar lipid content of at least about 15%
(w/w dry weight).
14. The process of claim 1, wherein the vegetative plant part
comprises a total TAG content of at least about 11% (w/w dry
weight).
15. The process of claim 1, wherein the vegetative plant part has
one or more or all of the following features: i) oleic acid
comprises at least 19% of the total fatty acid content in the
non-polar lipid in the vegetative plant part, ii) palmitic acid
comprises at least 20% of the total fatty acid content in the
non-polar lipid in the vegetative plant part, iii) linoleic acid
comprises at least 15% of the total fatty acid content in the
non-polar lipid in the vegetative plant part, and iv)
.alpha.-linolenic acid comprises less than 15% of the total fatty
acid content in the non-polar lipid in the vegetative plant
part.
16. The process of claim 1, in which at least some of the lipid is
converted to the industrial product by chemical means, wherein i)
the chemical means comprises reacting the non-polar lipid with an
alcohol, optionally in the presence of a catalyst, to produce alkyl
esters, and ii) optionally, blending the alkyl esters of step i)
with petroleum based fuel.
17. The process of claim 16, wherein the alkyl esters are methyl
esters.
18. The process of claim 1, wherein the industrial product is
synthetic diesel fuel and the process comprises: i) converting the
non-polar lipid in the vegetative plant part, or the processed
vegetative plant part, to a syngas by gasification, and ii)
converting the syngas to the synthetic diesel fuel in a process
comprising using a metal catalyst or a microbial catalyst.
19. The process of claim 1, wherein the industrial product is a
biofuel which is bio-oil or biogas, and the process comprises
converting the non-polar lipid in the vegetative plant part or the
processed vegetative plant part to the bio-oil by pyrolysis, or to
the biogas by gasification or anaerobic digestion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional Patent
Application No. 61/718,563, filed Oct. 25, 2012, and U.S.
Provisional Patent Application No. 61/580,590, filed Dec. 27, 2011,
the entire contents of each of which are hereby incorporated by
reference into the subject application.
REFERENCE TO A SEQUENCE LISTING
[0002] This application incorporates-by-reference nucleotide and/or
amino acid sequences which are present in the file named
"140521_2251_83668-AA_Sequence_listing_LC.txt." which is 1.22
megabytes in size, and which was created May 19, 2014 in the IBM-PC
machine format, having an operating system compatibility with
MS-Windows, which is contained in the text file filed May 21, 2014
as part of this application.
FIELD OF THE INVENTION
[0003] The present invention relates to methods of producing
industrial products such as hydrocarbon products from lipids
produced in plants, particularly in vegetative parts of plants, and
in algae and other non-human organisms. In particular, the present
invention provides plants having an increased level of one or more
non-polar lipids such as triacylglycerols and an increased total
non-polar lipid content. In one particular embodiment, the present
invention relates to any combination of lipid handling enzymes, oil
body proteins and/or transcription factors regulating lipid
biosynthesis to increase the level of one or more non-polar lipids
and/or the total non-polar lipid content and/or mono-unsaturated
fatty acid content in plants or any part thereof including plant
seed and/or leaves, algae and fungi. In an embodiment, the
conversion of the lipid to the hydrocarbon products occurs in
harvested plant vegetative parts to produce alkyl esters of the
fatty acids which are suitable for use as a renewable biodiesel
fuel.
BACKGROUND OF INVENTION
[0004] The majority of the world's energy, particularly for
transportation, is supplied by petroleum derived fuels, which have
a finite supply. Alternative sources which are renewable are
needed, such as from biologically produced oils.
Triacylglcerol Biosynthesis
[0005] Triaclyglycerols (TAG) constitute the major form of lipids
in seeds and consist of three acyl chains esterified to a glycerol
backbone. The fatty acids are synthesized in the plastid as
acyl-acyl carrier protein (ACP) intermediates where they can
undergo a first desaturation catalyzed. This reaction is catalyzed
by the stearoyl-ACP desaturase and yields oleic acid
(C18:1.sup..DELTA.9). Subsequently, the acyl chains are transported
to the cytosol and endoplasmic reticulum (ER) as acyl-Coenzyme
(CoA) esters. Prior to entering the major TAG biosynthesis pathway,
also known as the Kennedy or glycerol-3-phosphate (G3P) pathway,
the acyl chains are typically integrated into phospholipids of the
ER membrane where they can undergo further desaturation. Two key
enzymes in the production of polyunsaturated fatty acids are the
membrane-bound FAD2 and FAD3 desaturases which produce linoleic
(C18:2.sup..DELTA.9,12) and .alpha.-linolenic acid
(C18:3.sup..DELTA.9,12,15) respectively.
[0006] TAG biosynthesis via the Kennedy pathway consists of a
series of subsequent acylations, each using acyl-CoA esters as the
acyl-donor. The first acylation step typically occurs at the
sn1-position of the G3P backbone and is catalyzed by the
glycerol-3-phosphate acyltransferase (sn1-GPAz). The product,
sn1-lysophosphatidic acid (sn1-LPA) serves as a substrate for the
lysophosphatidic acid acyltransferase (LPAAT) which couples a
second acyl chain at the sn2-position to form phosphatidic acid. PA
is further dephosphorylated to diacylglycerol (DAG) by the
phosphatidic acid phosphatase (PAP) thereby providing the substrate
for the final acylation step. Finally, a third acyl chain is
esterified to the sn3-position of DAG in a reaction catalyzed by
the diacylglycerol acyltransferase (DGAT) to form TAG which
accumulates in oil bodies. A second enzymatic reaction,
phosphatidyl glycerol acyltransferase (PDAT), also results in the
conversion of DAG to TAG. This reaction is unrelated to DGAT and
uses phospholipids as the acyl-donors.
[0007] To maximise yields for the commercial production of lipids,
there is a need for further means to increase the levels of lipids,
particularly non-polar lipids such as DAGs and TAGs, in transgenic
organisms or parts thereof such as plants, seeds, leaves, algae and
fungi. Attempts at increasing neutral lipid yields in plants have
mainly focused on individual critical enzymatic steps involved in
fatty acid biosynthesis or TAG assembly. These strategies, however,
have resulted in modest increases in seed or leaf oil content.
Recent metabolic engineering work in the oleaginous yeast Yarrowia
lipolytica has demonstrated that a combined approach of increasing
glycerol-3-phosphate production and preventing TAG breakdown via
.beta.-oxidation resulted in cumulative increases in the total
lipid content (Dulermo et al., 2011).
[0008] Plant lipids such as seedoil triaclyglycerols (TAGs) have
many uses, for example, culinary uses (shortening, texture,
flavor), industrial uses (in soaps, candles, perfumes, cosmetics,
suitable as drying agents, insulators, lubricants) and provide
nutritional value. There is also growing interest in using plant
lipids for the production of biofuel.
[0009] To maximise yields for the commercial biological production
of lipids, there is a need for further means to increase the levels
of lipids, particularly non-polar lipids such as DAGs and TAGs, in
transgenic organisms or parts thereof such as plants, seeds,
leaves, algae and fungi.
SUMMARY OF THE INVENTION
[0010] The present inventors have demonstrated significant
increases in the lipid content of organisms, particularly in the
vegetative parts and seed of plants, by manipulation of both fatty
acid biosynthesis and lipid assembly pathways. Various combinations
of genes were used to achieve substantial increases in oil content,
which is of great significance for production of biofuels and other
industrial products derived from oil.
[0011] In a first aspect, the invention provides a process for
producing an industrial product from a vegetative plant part or
non-human organism or part thereof comprising high levels of
non-polar lipid.
[0012] In an embodiment, the present invention provides a process
for producing an industrial product, the process comprising the
steps of:
[0013] i) obtaining a vegetative plant part having a total
non-polar lipid content of at least 10% (w/w dry weight),
[0014] ii) either [0015] a) converting at least some of the lipid
in the vegetative plant part of step i) to the industrial product
by applying heat, chemical, or enzymatic means, or any combination
thereof, to the lipid in situ in the vegetative plant part, or
[0016] b) physically processing the vegetative plant part of step
i), and subsequently or simultaneously converting at least some of
the lipid in the processed vegetative plant part to the industrial
product by applying heat, chemical, or enzymatic means, or any
combination thereof; to the lipid in the processed vegetative plant
part, and
[0017] iii) recovering the industrial product, thereby producing
the industrial product.
[0018] In another embodiment, the invention provides a process for
producing an industrial product, the process comprising the steps
of:
[0019] i) obtaining a vegetative plant part having a total
non-polar lipid content of at least about 3%, preferably at least
about 5% or at least about 7% (w/w dry weight),
[0020] ii) converting at least some of the lipid in situ in the
vegetative plant part to the industrial product by heat, chemical,
or enzymatic means, or any combination thereof, and
[0021] iii) recovering the industrial product,
thereby producing the industrial product.
[0022] In another embodiment, the process for producing an
industrial product comprises the steps of:
[0023] i) obtaining a vegetative plant part having a total
non-polar lipid content of at least about 3%, preferably at least
about 5% or at least about 7% (w/w dry weight),
[0024] ii) physically processing the vegetative plant part of step
i),
[0025] iii) converting at least some of the lipid in the processed
vegetative plant part to the industrial product by applying heat,
chemical, or enzymatic means, or any combination thereof, to the
lipid in the processed vegetative plant part, and
[0026] iv) recovering the industrial product, thereby producing the
industrial product.
[0027] In another embodiment, the process for producing an
industrial product comprises the steps of:
[0028] i) obtaining a non-human organism or a part thereof
comprising one or more exogenous polynucleotide(s), wherein each of
the one or more exogenous polynucleotide(s) is operably linked to a
promoter which is capable of directing expression of the
polynucleotide in a non-human organism or a part thereof, and
wherein the non-human organism or part thereof has an increased
level of one or more non-polar lipids relative to a corresponding
non-human organism or a part thereof lacking the one or more
exogenous polynucleotide(s), and
[0029] ii) converting at least some of the lipid in situ in the
non-human organism or part thereof to the industrial product by
heat, chemical, or enzymatic means, or any combination thereof,
and
[0030] iii) recovering the industrial product, thereby producing
the industrial product.
[0031] In a further embodiment, the process for producing an
industrial product comprises the steps of:
[0032] i) obtaining a non-human organism or a part thereof
comprising one or more exogenous polynucleotides, wherein the
non-human organism or part thereof has an increased level of one or
more non-polar lipids relative to a corresponding non-human
organism or a part thereof lacking the one or more exogenous
polynucleotides,
[0033] ii) physically processing the non-human organism or part
thereof of step i),
[0034] iii) converting at least some of the lipid in the processed
non-human organism or part thereof to the industrial product by
applying heat, chemical, or enzymatic means, or any combination
thereof, to the lipid in the processed non-human organism or part
thereof, and
[0035] iv) recovering the industrial product,
thereby producing the industrial product.
[0036] In each of the above embodiments, it would be understood by
a person skilled in the art that the converting step could be done
simultaneously with or subsequent to the physical processing
step.
[0037] In each of the above embodiments, the total non-polar lipid
content of the vegetative plant part, or non-human organism or part
thereof, preferably a plant leaf or part thereof, stem or tuber, is
at least about 3%, more preferably at least about 5%, preferably at
least about 7%, more preferably at least about 10%, more preferably
at least about 11%, more preferably at least about 12%, more
preferably at least about 13%, more preferably at least about 14%,
or more preferably at least about 15% (w/w dry weight). In a
further preferred embodiment, the total non-polar lipid content is
between 5% and 25%, between 7% and 25%, between 10% and 25%,
between 12% and 25%, between 15% and 25%, between 7% and 20%,
between 10% and 20%, between 10% and 15%, between 15% and 20%,
between 20% and 25%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
or about 22%, each as a percentage of dry weight In a particularly
preferred embodiment, the vegetative plant part is a leaf (or
leaves) or a portion thereof. In a more preferred embodiment, the
vegetative plant part is a leaf portion having a surface area of at
least 1 cm.sup.2.
[0038] Furthermore, in each of the above embodiments, the total TAG
content of the vegetative plant part, or non-human organism or part
thereof, preferably a plant leaf or part thereof, stem or tuber, is
at least about 3%, more preferably at least about 5%, preferably at
least about 7%, more preferably at least about 10%, more preferably
at least about 11%, more preferably at least about 12%, more
preferably at least about 13%, more preferably at least about 14%,
more preferably at least about 15%, or more preferably at least
about 17% (w/w dry weight). In a further preferred embodiment, the
total TAG content is between 5% and 30%, between 7% and 30%,
between 10% and 30%, between 12% and 30%, between 15% and 30%,
between 7% and 30%, between 10% and 30%, between 20% and 28%,
between 18% and 25%, between 22% and 30%, about 10%, about 11%,
about 12%, about 13%, about 14%, about 15%, about 16%, about 17%,
about 18%, about 20%, or about 22%, each as a percentage of dry
weight. In a particularly preferred embodiment, the vegetative
plant part is a leaf (or leaves) or a portion thereof. In a more
preferred embodiment, the vegetative plant part is a leaf portion
having a surface area of at least 1 cm.sup.2.
[0039] Furthermore, in each of the above embodiments, the total
lipid content of the vegetative plant part, or non-human organism
or part thereof, preferably a plant leaf or part thereof, stem or
tuber, is at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, more preferably at least about 15%, more preferably at
least about 17% (w/w dry weight), more preferably at least about
20%, more preferably at least about 25%. In a further preferred
embodiment, the total lipid content is between 5% and 35%, between
7% and 35%, between 10% and 35%, between 12% and 35%, between 15%
and 35%, between 7% and 35%, between 10% and 20%, between 18% and
28%, between 20% and 28%, between 22% and 28%, about 10%, about
11%, about 12%, about 13%, about 14%, about 15%, about 16%, about
17%, about 18%, about 20%, about 22%, or about 25%, each as a
percentage of dry weight. Typically, the total lipid content of the
vegetative plant part, or non-human organism or part thereof is
about 2-3% higher than the non-polar lipid content. In a
particularly preferred embodiment, the vegetative plant part is a
leaf (or leaves) or a portion thereof. In a more preferred
embodiment, the vegetative plant part is a leaf portion having a
surface area of at least 1 cm.sup.2.
[0040] The industrial product may be a hydrocarbon product such as
fatty acid esters, preferably fatty acid methyl esters and/or a
fatty acid ethyl esters, an alkane such as methane, ethane or a
longer-chain alkane, a mixture of longer chain alkanes, an alkene,
a biofuel, carbon monoxide and/or hydrogen gas, a bioalcohol such
as ethanol, propanol, or butanol, biochar, or a combination of
carbon monoxide, hydrogen and biochar. The industrial product may
be a mixture of any of these components, such as a mixture of
alkanes, or alkanes and alkenes, preferably a mixture which is
predominantly (>50%) C4-C8 alkanes, or predominantly C6 to C10
alkanes, or predominantly C6 to C8 alkanes. The industrial product
is not carbon dioxide and not water, although these molecules may
be produced in combination with the industrial product. The
industrial product may be a gas at atmospheric pressure/room
temperature, or preferably, a liquid, or a solid such as biochar,
or the process may produce a combination of a gas component, a
liquid component and a solid component such as carbon monoxide,
hydrogen gas, alkanes and biochar, which may subsequently be
separated. In an embodiment, the hydrocarbon product is
predominantly fatty acid methyl esters. In an alternative
embodiment, the hydrocarbon product is a product other than fatty
acid methyl esters.
[0041] The industrial product may be an intermediate product, for
example, a product comprising fatty acids, which can subsequently
be converted to, for example, biofuel by, for example,
trans-esterification to fatty acid esters.
[0042] Heat may be applied in the process, such as by pyrolysis,
combustion, gasification, or together with enzymatic digestion
(including anaerobic digestion, composting, fermentation). Lower
temperature gasification takes place at, for example, between about
700.degree. C. to about 1000.degree. C. Higher temperature
gasification takes place at, for example, between about
1200.degree. C. to about 1600.degree. C. Lower temperature
pyrolysis (slower pyrolysis), takes place at, for example, about
400.degree. C., whereas higher temperature pyrolysis takes place
at, for example, about 500.degree. C. Mesophilic digestion takes
place between, for example, about 20.degree. C. and about
40.degree. C. Thermophilic digestion takes place from, for example,
about 50.degree. C. to about 65.degree. C.
[0043] Chemical means include, but are not limited to, catalytic
cracking, anaerobic digestion, fermentation, composting and
transesterification. In an embodiment, a chemical means uses a
catalyst or mixture of catalysts, which may be applied together
with heat. The process may use a homogeneous catalyst, a
heterogeneous catalyst and/or an enzymatic catalyst. In an
embodiment, the catalyst is a transition metal catalyst, a
molecular sieve type catalyst, an activated alumina catalyst or
sodium carbonate. Catalysts include acid catalysts such as
sulphuric acid, or alkali catalysts such as potassium or sodium
hydroxide or other hydroxides. The chemical means may comprise
transesterification of fatty acids in the lipid, which process may
use a homogeneous catalyst, a heterogeneous catalyst and/or an
enzymatic catalyst. The conversion may comprise pyrolysis, which
applies heat and may apply chemical means, and may use a transition
metal catalyst, a molecular sieve type catalyst, an activated
alumina catalyst and/or sodium carbonate.
[0044] Enzymatic means include, but are not limited to, digestion
by microorganisms in, for example, anaerobic digestion,
fermentation or composting, or by recombinant enzymatic
proteins.
[0045] The lipid that is converted to an industrial product in this
aspect of the invention may be some, or all, of the non-polar lipid
in the vegetative plant part or non-human organism or part thereof;
or preferably the conversion is of at least some of the non-polar
lipid and at least some of the polar lipid, and more preferably
essentially all of the lipid (both polar and non-polar) in the
vegetative plant part or non-human organism or part thereof is
converted to the industrial product(s).
[0046] In an embodiment, the conversion of the lipid to the
industrial product occurs in situ without physical disruption of
the vegetative plant part or non-human organism or part thereof. In
this embodiment, the vegetative plant part or non-human organism or
part thereof may first be dried, for example by the application of
heat, or the vegetative plant part or non-human organism or part
thereof may be used essentially as harvested, without drying. In an
alternative embodiment, the process comprises a step of physically
processing the vegetative plant part, or the non-human organism or
part thereof. The physical processing may compriseone or more of
rolling, pressing such as flaking, crushing or grinding the
vegetative plant part, non human organism or part thereof, which
may be combined with drying of the vegetative plant part, or the
non-human organism or part thereof. For example, the vegetative
plant part, or non-human organism or part thereof may first be
substantially dried and then ground to a finer material, for ease
of subsequent processing.
[0047] In an embodiment, the weight of the vegetative plant part,
or the non-human organism or part thereof used in the process is at
least 1 kg or preferably at least 1 tonne (dry weight) of pooled
vegetative plant parts, or the non-human organisms or parts
thereof. The processes may further comprise a first step of
harvesting vegetative plant parts, for example from at least 100 or
1000 plants grown in a field, to provide a collection of at least
1000 such vegetative plant parts, i.e., which are essentially
identical. Preferably, the vegetative plant parts are harvested at
a time when the yield of non-polar lipids are at their highest. In
one embodiment, the vegetative plant parts are harvested about at
the time of flowering. In another embodiment, the vegetative plant
parts are harvested from about at the time of flowering to about
the beginning of senescence. In another embodiment, the vegetative
plant parts are harvested when the plants are at least about 1
month of age.
[0048] The process may or may not further comprise extracting some
of the non-polar lipid content of the vegetative plant part, or the
non-human organism or part thereof prior to the conversion step. In
an embodiment, the process further comprises steps of:
[0049] (a) extracting at least some of the non-polar lipid content
of the vegetative plant part or the non-human organism or part
thereof as non-polar lipid, and
[0050] (b) recovering the extracted non-polar lipid, wherein steps
(a) and (b) are performed prior to the step of converting at least
some of the lipid in the vegetative plant part, or the non-human
organism or part thereof to the industrial product. The proportion
of non-polar lipid that is first extracted may be less than 50%, or
more than 50%, or preferably at least 75% of the total non-polar
lipid in the vegetative plant part, or non-human organism or part
thereof. In this embodiment, the extracted non-polar lipid
comprises triacylglycerols, wherein the triacylglycerols comprise
at least 90%, preferably at least 95% of the extracted lipid. The
extracted lipid may itself be converted to an industrial product
other than the lipid itself, for example by trans-esterification to
fatty acid esters.
[0051] In a second aspect, the invention provides a process for
producing extracted lipid from a non-human organism or a part
thereof.
[0052] In an embodiment, the present invention provides a process
for producing extracted lipid, the process comprising the steps
of:
[0053] i) obtaining a non-human organism or a part thereof, wherein
the non-human organism or part thereof has a total non-polar lipid
content of at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, or more preferably at least about 15% (w/w dry weight or
seed weight),
[0054] ii) extracting lipid from the non-human organism or part
thereof; and
[0055] iii) recovering the extracted lipid,
[0056] thereby producing the extracted lipid, wherein one or more
or all of the following features apply:
[0057] (a) the non-human organism or a part thereof comprises one
or more exogenous polynucleotide(s) and an increased level of one
or more non-polar lipid(s) relative to a corresponding non-human
organism or a part thereof, respectively, lacking the one or more
exogenous polynucleotide(s), wherein each of the one or more
exogenous polynucleotides is operably linked to a promoter which is
capable of directing expression of the polynucleotide in a
non-human organism or part thereof,
[0058] (b) the non-human organism is an alga selected from the
group consisting of diatoms (bacillariophytes), green algae
(chlorophytes), blue-green algae (cyanophytes), golden-brown algae
(chrysophytes), haptophytes, brown algae and heterokont algae,
[0059] (c) the one or more non-polar lipid(s) comprise a fatty acid
which comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains,
[0060] (d) the total fatty acid content in the non-polar lipid(s)
comprises at least 2% more oleic acid and/or at least 2% less
palmitic acid than the non-polar lipid(s) in the corresponding
non-human organism or part thereof lacking the one or more
exogenous polynucleotides of part (a),
[0061] (e) the non-polar lipid(s) comprise a modified level of
total sterols, preferably free (non-esterified) sterols, steroyl
esters, steroyl glycosides, relative to the non-polar lipid(s) in
the corresponding non-human organism or part thereof lacking the
one or more exogenous polynucleotides of part (a),
[0062] (f) the non-polar lipid(s) comprise waxes and/or wax
esters,
[0063] (g) the non-human organism or part thereof is one member of
a pooled population or collection of at least about 1000 such
non-human organisms or parts thereof, respectively, from which the
lipid is extracted.
[0064] In another embodiment, the invention provides a process for
producing extracted lipid, the process comprising the steps of:
[0065] i) obtaining a non-human organism or a part thereof
comprising one or more exogenous polynucleotide(s) and an increased
level of one or more non-polar lipid(s) relative to a corresponding
non-human organism or a part thereof, respectively, lacking the one
or more exogenous polynucleotide(s),
[0066] ii) extracting lipid from the non-human organism or part
thereof; and
[0067] iii) recovering the extracted lipid,
thereby producing the extracted lipid, wherein each of the one or
more exogenous polynucleotides is operably linked to a promoter
which is capable of directing expression of the polynucleotide in a
non-human organism or part thereof, and wherein one or more or all
of the following features apply:
[0068] (a) the one or more exogenous polynucleotide(s) comprise a
first exogenous polynucleotide which encodes an RNA or
transcription factor polypeptide that increases the expression of
one or more glycolytic or fatty acid biosynthetic genes in a
non-human organism or a part thereof, and a second exogenous
polynucleotide which encodes an RNA or polypeptide involved in
biosynthesis of one or more non-polar lipids,
[0069] (b) if the non-human organism is a plant, a vegetative part
of the plant has a total non-polar lipid content of at least about
3%, more preferably at least about 5%, preferably at least about
7%, more preferably at least about 10%, more preferably at least
about 11%, more preferably at least about 12%, more preferably at
least about 13%, more preferably at least about 14%, or more
preferably at least about 15% (w/w dry weight),
[0070] (c) the non-human organism is an alga selected from the
group consisting of diatoms (bacillariophytes), green algae
(chlorophytes), blue-green algae (cyanophytes), golden-brown algae
(chrysophytes), haptophytes, brown algae and heterokont algae,
[0071] (d) the one or more non-polar lipid(s) comprise a fatty acid
which comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains,
[0072] (e) the total fatty acid content in the non-polar lipid(s)
comprises at least 2% more oleic acid and/or at least 2% less
palmitic acid than the non-polar lipid(s) in the corresponding
non-human organism or part thereof lacking the one or more
exogenous polynucleotides,
[0073] (f) the non-polar lipid(s) comprise a modified level of
total sterols, preferably free (non-esterified) sterols, steroyl
esters, steroyl glycosides, relative to the non-polar lipid(s) in
the corresponding non-human organism or part thereof lacking the
one or more exogenous polynucleotides,
[0074] (g) the non-polar lipid(s) comprise waxes and/or wax
esters,
[0075] (h) the non-human organism or part thereof is one member of
a pooled population or collection of at least 1000 such non-human
organisms or parts thereof, respectively, from which the lipid is
extracted.
[0076] In an embodiment of (b) above, the total non-polar lipid
content is between 5% and 25%, between 7% and 25%, between 10% and
25%, between 12% and 25%, between 15% and 25%, between 7% and 20%,
between 10% and 20%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
or about 22%, each as a percentage of dry weight.
[0077] In an embodiment, the non-human organism is an alga, or an
organism suitable for fermentation such as a fungus, or preferably
a plant. The part of the non-human organism may be a seed, fruit,
or a vegetative part of a plant. In a preferred embodiment, the
plant part is a leaf portion having a surface area of at least 1
cm.sup.2. In another preferred embodiment, the non-human organism
is a plant, the part is a plant seed and the extracted lipid is
seedoil. In a more preferred embodiment, the plant is from an
oilseed species, which is used commercially or could be used
commercially for oil production. The species may be selected from a
group consisting of a Acrocomia aculeata (macauba palm),
Arabidopsis thaliana, Aracinis hypogaea (peanut), Astrocaryum
murumuru (murumuru), Astrocaryum vulgare (tucuma), Attalea
geraensis (Indaia-rateiro), Attalea humilis (American oil palm),
Attalea oleifera (andaia), Attalea phalerata (uricuri), Attalea
speciosa (babassu), Avena saliva (oats), Beta vulgaris (sugar
beet), Brassica sp. such as Brassica carinala, Brassica juncea,
Brassica napobrassica, Brassica napus (canola), Camelina saliva
(false flax), Cannabis sativa (hemp), Carthamus tinctorius
(safflower), Caryocar brasiliense (pequi), Cocos nucifera
(Coconut), Crambe abyssinica (Abyssinian kale), Cucumis melo
(melon), Elaeis guineensis (African palm), Glycine max (soybean),
Gossypium hirsutum (cotton), Helianthus sp. such as Helianthus
annuus (sunflower), Hordeum vulgare (barley), Jatropha curcas
(physic nut), Joannesia princeps (arara nut-tree), Lemna sp.
(duckweed) such as Lemna aequinoctialis, Lemna disperma, Lemna
ecuadoriensis, Lemna gibba (swollen duckweed), Lemna japonica,
Lemna minor, Lemna minuta, Lemna obscura, Lemna paucicostata, Lemna
perpusilla, Lemna lenera, Lemna trisulca, Lemna turionifera, Lemna
valdiviana, Lemna yungensis, Licania rigida (oiticica), Linum
usitatissimum (flax), Lupinus angustifolius (lupin), Mauritia
flexuosa (buriti palm), Maximiliana maripa (inaja palm), Miscanthus
sp. such as Miscanthus x giganteus and Miscanthus sinensis,
Nicotiana sp. (tabacco) such as Nicotiana tabacum or Nicotiana
benthamiana, Oenocarpus bacaba (bacaba-do-azeite), Oenocarpus
bataua (pataua), Oenocarpus distichus (bacaba-de-leque), Oryza sp.
(rice) such as Oryza sativa and Oryza glaberrima, Panicum virgatum
(switchgrass), Paraqueiba paraensis (mari), Persea amencana
(avocado), Pongamia pinnata (Indian beech), Populus trichocarpa,
Ricinus communis (castor), Saccharum sp. (sugarcane), Sesamum
indicum (sesame), Solanum tuberosum (potato), Sorghum sp. such as
Sorghum bicolor, Sorghum vulgare, Theobroma grandiforum (cupuassu),
Trifolium sp., Trithrinax brasiliensis (Brazilian needle palm),
Triticum sp. (wheat) such as Triticum aestivum and Zea mays (corn).
In an embodiment, the Brassica napus plant is of the variety
Westar. In an alternative embodiment, if the plant is Brassica
napus, it is of a variety or cultivar other than Westar. In an
embodiment, the plant is of a species other than Arabidopsis
thaliana. In another embodiment, the plant is of a species other
than Nicotiana tabacum. In another embodiment, the plant is of a
species other than Nicotiana benthamiana. In one embodiment, the
plant is a perennial, for example, a switchgrass. Each of the
features described for the plant of the second aspect can be
applied mutatis mutandis to the vegetative plant part of the first
aspect.
[0078] In an embodiment, the non-human organism is an oleaginous
fungus such as an oleaginous yeast.
[0079] In a preferred embodiment, the lipid is extracted without
drying the non-human organism or part thereof prior to the
extraction. The extracted lipid may subsequently be dried or
fractionated to reduce its moisture content.
[0080] In further embodiments of this aspect, the invention
provides a process for producing extracted lipid from specific
oilseed plants. In an embodiment, the invention provides a process
for producing extracted canola oil, the process comprising the
steps of: [0081] i) obtaining canola seed comprising at least 45%
seedoil on a weight basis, [0082] ii) extracting oil from the
canola seed, and [0083] iii) recovering the oil, wherein the
recovered oil comprises at least 90% (w/w) triacylglycerols (TAG),
thereby producing the canola oil. In a preferred embodiment, the
canola seed has an oil content on a weight basis of at least 46%,
at least 47%, at least 48%, at least 49%, at least 50%, at least
51%, at least 52%, at least 53%, at least 54%, at least 55% or at
least 56%. The oil content is determinable by measuring the amount
of oil that is extracted from the seed, which is threshed seed as
commonly harvested, and calculated as a percentage of the seed
weight, i.e., % (w/w). Moisture content of the canola seed is
between 5% and 15%, and is preferably about 8.5%. In an embodiment,
the oleic acid content is between about 58% and 62% of the total
fatty acid in the canola oil, preferably at least 63%, and the
palmitic acid content is about 4% to about 6% of the total fatty
acids in the canola oil. Preferred canola oil has an iodine value
of 110-120 and a chlorophyll level of less than 30 ppm.
[0084] In another embodiment, the invention provides a process for
producing extracted cornseed oil, the process comprising the steps
of:
[0085] i) obtaining corn seed comprising at least 5% seedoil on a
weight basis,
[0086] ii) extracting oil from the corn seed, and
[0087] iii) recovering the oil, wherein the recovered oil comprises
at least 80.degree. %, [0088] preferably at least 85% or at least
90% (w/w) triacylglycerols (TAG), thereby producing the cornseed
oil. In a preferred embodiment, the corn seed has an oil content on
a seed weight basis (w/w) of at least 6%, at least 7%, at least 8%,
at least 9%, at least 10%, at least 11%, at least 12% or at least
13%. The moisture content of the cornseed is about 13% to about
17%, preferably about 15%. Preferred corn oil comprises about 0.1%
tocopherols.
[0089] In another embodiment, the invention provides a process for
producing extracted soybean oil, the process comprising the steps
of: [0090] i) obtaining soybean seed comprising at least 20.degree.
% seedoil on a weight basis, [0091] ii) extracting oil from the
soybean seed, and [0092] iii) recovering the oil, wherein the
recovered oil comprises at least 90% (w/w) triacylglycerols (TAG),
thereby producing the soybean oil. In a preferred embodiment, the
soybean seed has an oil content on a seed weight basis (w/w) of at
least 21%, at least 22%, at least 23%, at least 24%, at least 25%,
at least 26%, at least 27%, at least 28%, at least 29%, at least
30%, or at least 31%. In an embodiment, the oleic acid content is
between about 20% and about 25% of the total fatty acid in the
soybean oil, preferably at least 30%, the linoleic acid content is
between about 45% and about 57%, preferably less than 45%, and the
palmitic acid content is about 10% to about 15% of the total fatty
acids in the soybean oil, preferably less than 10%. Preferably the
soybean seed has a protein content of about 40% on a dry weight
basis, and the moisture content of the soybean seed is about 10% to
about 16%, preferably about 13%.
[0093] In another embodiment, the invention provides a process for
producing extracted lupinseed oil, the process comprising the steps
of: [0094] i) obtaining lupin seed comprising at least 10% seedoil
on a weight basis, [0095] ii) extracting oil from the lupin seed,
and [0096] iii) recovering the oil, wherein the recovered oil
comprises at least 90% (w/w) triacylglycerols (TAG), thereby
producing the lupinseed oil. In a preferred embodiment, the lupin
seed has an oil content on a seed weight basis (w/w) of at least
11%, at least 12%, at least 13%, at least 14%, at least 15%, or at
least 16%.
[0097] In another embodiment, the invention provides a process for
producing extracted peanut oil, the process comprising the steps
of: [0098] i) obtaining peanuts comprising at least 50% seedoil on
a weight basis, [0099] ii) extracting oil from the peanuts, and
[0100] iii) recovering the oil, wherein the recovered oil comprises
at least 90% (w/w) triacylglycerols (TAG), thereby producing the
peanut oil. In a preferred embodiment, the peanut seed (peanuts)
have an oil content on a seed weight basis (w/w) of at least 51%,
at least 52%, at least 53%, at least 54%, at least 55% or at least
56%. In an embodiment, the oleic acid content is between about 38%
and 59%.sup.0 of the total fatty acid in the peanut oil, preferably
at least 60%, and the palmitic acid content is about 9% to about
13% of the total fatty acids in the peanut oil, preferably less
than 9%.
[0101] In another embodiment, the invention provides a process for
producing extracted sunflower oil, the process comprising the steps
of: [0102] i) obtaining sunflower seed comprising at least 50%
seedoil on a weight basis, [0103] ii) extracting oil from the
sunflower seed, and [0104] iii) recovering the oil, wherein the
recovered oil comprises at least 90% (w/w) triacylglycerols (TAG),
thereby producing the sunflower oil. In a preferred embodiment, the
sunflower seed have an oil content on a seed weight basis (w/w) of
at least 51%, at least 52%, at least 53%, at least 54%, or at least
55%.
[0105] In another embodiment, the invention provides a process for
producing extracted cottonseed oil, the process comprising the
steps of: [0106] i) obtaining cottonseed comprising at least 41%
seedoil on a weight basis, [0107] ii) extracting oil from the
cottonseed, and [0108] iii) recovering the oil, wherein the
recovered oil comprises at least 90% (w/w) triacylglycerols (TAG),
thereby producing the cottonseed oil. In a preferred embodiment,
the cotton seed have an oil content on a seed weight basis (w/w) of
at least 42%, at least 43%, at least 44%, at least 45%, at least
46%, at least 47%, at least 48%, at least 49%, or at least 50%. In
an embodiment, the oleic acid content is between about 15% and 22%
of the total fatty acid in the cotton oil, preferably at least 22%,
the linoleic acid content is between about 45% and about 57%,
preferably less than 45%, and the palmitic acid content is about
20% to about 26% of the total fatty acids in the cottonseed oil,
preferably less than 18%. In an embodiment, the cottonseed oil also
contains cyclopropanated fatty acids such as sterculic and malvalic
acids, and may contain small amounts of gossypol.
[0109] In another embodiment, the invention provides a process for
producing extracted safflower oil, the process comprising the steps
of: [0110] i) obtaining safflower seed comprising at least 35%
seedoil on a weight basis, [0111] ii) extracting oil from the
safflower seed, and [0112] iii) recovering the oil, wherein the
recovered oil comprises at least 90% (w/w) triacylglycerols (TAG),
thereby producing the safflower oil. In a preferred embodiment, the
safflower seed have an oil content on a seed weight basis (w/w) of
at least 36%, at least 37%, at least 38%, at least 39%, at least
40%, at least 41%, at least 42%, at least 43%, at least 44%, or at
least 45%.
[0113] In another embodiment, the invention provides a process for
producing extracted flaxseed oil, the process comprising the steps
of: [0114] i) obtaining flax seed comprising at least 36% seedoil
on a weight basis, [0115] ii) extracting oil from the flax seed,
and [0116] iii) recovering the oil, wherein the recovered oil
comprises at least 90% (w/w) triacylglycerols (TAG), thereby
producing the flaxseed oil. In a preferred embodiment, the flax
seed have an oil content on a seed weight basis (w/w) of at least
37%, at least 38%, at least 39%, or at least 40%.
[0117] In another embodiment, the invention provides a process for
producing extracted Camelina oil, the process comprising the steps
of: [0118] i) obtaining Camelina sativa seed comprising at least
36% seedoil on a weight basis, [0119] ii) extracting oil from the
Camelina sativa seed, and [0120] iii) recovering the oil, wherein
the recovered oil comprises at least 90% (w/w) triacylglycerols
(TAG), thereby producing the Camelina oil. In a preferred
embodiment, the Camelina saliva seed have an oil content on a seed
weight basis (w/w) of at least 37%, at least 38%, at least 39%, at
least 40%, at least 41%, at least 42%, at least 43%, at least 44%,
or at least 45%.
[0121] The process of the second aspect may also comprise measuring
the oil and/or protein content of the seed by near-infrared
reflectance spectroscopy as described in Hom et al. (2007).
[0122] In an embodiment, the process of the second aspect of the
invention comprises partially or completely drying the vegetative
plant part, or the non-human organism, or part thereof, or the
seed, and/or one or more of rolling, pressing such as flaking,
crushing or grinding the vegetative plant part, or the non-human
organism or part thereof, or the seed, or any combination of these
methods, in the extraction process. The process may use an organic
solvent (e.g., hexane such as n-hexane or a combination of n-hexane
with isohexane, or butane alone or in combination with hexane) in
the extraction process to extract the lipid or oil or to increase
the efficiency of the extraction process, particularly in
combination with a prior drying process to reduce the moisture
content.
[0123] In an embodiment, the process comprises recovering the
extracted lipid or oil by collecting it in a container, and/or
purifying the extracted lipid or seedoil, such as, for example, by
degumming, deodorising, decolourising, drying and/or fractionating
the extracted lipid or oil, and/or removing at least some,
preferably substantially all, waxes and/or wax esters from the
extracted lipid or oil. The process may comprise analysing the
fatty acid composition of the extracted lipid or oil, such as, for
example, by converting the fatty acids in the extracted lipid or
oil to fatty acid methyl esters and analysing these using GC to
determine the fatty acid composition. The fatty acid composition of
the lipid or oil is determined prior to any fractionation of the
lipid or oil that alters its fatty acid composition. The extracted
lipid or oil may comprise a mixture of lipid types and/or one or
more derivatives of the lipids, such as free fatty acids.
[0124] In an embodiment, the process of the second aspect of the
invention results in substantial quantities of extracted lipid or
oil. In an embodiment, the volume of the extracted lipid or oil is
at least 1 litre, preferably at least 10 litres. In a preferred
embodiment, the extracted lipid or oil is packaged ready for
transportation or sale.
[0125] In an embodiment, the extracted lipid or oil comprises at
least 91%, at least 92%, at least 93%, at least 94%, at least 95%
or at least 96% TAG on a weight basis. The extracted lipid or oil
may comprise phospholipid as a minor component, up to about 8% by
weight, preferably less than 5% by weight, and more preferably less
than 3% by weight.
[0126] In an embodiment, the process results in extracted lipid or
oil wherein one or more or all of the following features apply:
[0127] (i) triacylglycerols comprise at least 90%, preferably at
least 95% or 96%, of the extracted lipid or oil,
[0128] (ii) the extracted lipid or oil comprises free sterols,
steroyl esters, steroyl glycosides, waxes or wax esters, or any
combination thereof, and
[0129] (iii) the total sterol content and/or composition in the
extracted lipid or oil is significantly different to the sterol
content and/or composition in the extracted lipid or oil produced
from a corresponding non-human organism or part thereof, or
seed.
[0130] In an embodiment, the process further comprises converting
the extracted lipid or oil to an industrial product. That is, the
extracted lipid or oil is converted post-extraction to another
chemical form which is an industrial product. Preferably, the
industrial product is a hydrocarbon product such as fatty acid
esters, preferably fatty acid methyl esters and/or fatty acid ethyl
esters, an alkane such as methane, ethane or a longer-chain alkane,
a mixture of longer chain alkanes, an alkene, a biofuel, carbon
monoxide and/or hydrogen gas, a bioalcohol such as ethanol,
propanol, or butanol, biochar, or a combination of carbon monoxide,
hydrogen and biochar.
[0131] In the process of either the first or second aspects of the
invention, the vegetative plant part, or the part of the non-human
organism may be an aerial plant part or a green plant part such as
a plant leaf or stem, a woody part such as a stem, branch or trunk,
or a root or tuber. Preferably, the plants are grown in a field and
the parts such as seed harvested from the plants in the field.
[0132] In an embodiment, the process further comprises a step of
harvesting the vegetative plant part, non-human organism or part
thereof; preferably with a mechanical harvester.
[0133] Preferably, the vegetative plant parts are harvested at a
time when the yield of non-polar lipids are at their highest. In
one embodiment, the vegetative plant parts are harvested about at
the time of flowering. In another embodiment, the vegetative plant
parts are harvested from about at the time of flowering to about
the beginning of senescence. In another embodiment, the vegetative
plant parts are harvested when the plants are at least about 1
month of age.
[0134] If the organism is an algal or fungal organism, the cells
may be grown in an enclosed container or in an open-air system such
as a pond. The resultant organisms comprising the non-polar lipid
may be harvested, such as, for example, by a process comprising
filtration, centrifugation, sedimentation, flotation or
flocculation of algal or fungal organisms such as by adjusting pH
of the medium. Sedimentation is less preferred.
[0135] In the process of the second aspect of the invention, the
total non-polar lipid content of the non-human organism or part
thereof, such a vegtative plant part or seed, is increased relative
to a corresponding vegetative plant part, non-human organism or
part thereof, or seed.
[0136] In an embodiment, the vegetative plant part, or non-human
organism or part thereof, or seed of the first or second aspects of
the invention is further defined by three features, namely Feature
(i), Feature (ii) and Feature (iii), singly or in combination:
[0137] Feature (i) quantifies the extent of the increased level of
the one or more non-polar lipids or the total non-polar lipid
content of the vegetative plant part, or non-human organism or part
thereof, or seed which may be expressed as the extent of increase
on a weight basis (dry weight basis or seed weight basis), or as
the relative increase compared to the level in the corresponding
vegetative plant part, or non-human organism or part thereof, or
seed. Feature (ii) specifies the plant genus or species, or the
fungal or algal species, or other cell type, and Feature (iii)
specifies one or more specific lipids that are increased in the
non-polar lipid content.
[0138] For Feature (i), in an embodiment, the extent of the
increase of the one or more non-polar lipids is at least 0.5%, at
least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at
least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at
least 11%, at least 12%, at least 13%, at least 14%, at least 15%,
at least 16%, at least 17%, at least 18%, at least 19%, at least
20%, at least 21%, at least 22%, at least 23%, at least 24%, at
least 25% or at least 26% greater on a dry weight or seed weight
basis than the corresponding vegetative plant part, or non-human
organism or part thereof.
[0139] Also for Feature (i), in a preferred embodiment, the total
non-polar lipid content of the vegetative plant part, or non-human
organism or part thereof or seed is increased when compared to the
corresponding vegetative plant part, or non-human organism or part
thereof, or seed. In an embodiment, the total non-polar lipid
content is increased by at least 0.5%, at least 1%, at least 2%, at
least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at
least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at
least 13%, at least 14%, at least 15%, at least 16%, at least 17%,
at least 18%, at least 19%, at least 20%, at least 21%, at least
22%, at least 23%, at least 24%, at least 25% or at least 26%
greater on a dry weight or seed weight basis than the corresponding
vegetative plant part, or non-human organism or part thereof, or
seed.
[0140] Further, for Feature (i), in an embodiment, the level of the
one or more non-polar lipids and/or the total non-polar lipid
content is at least 1%, at least 2%, at least 3%, at least 4%, at
least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at
least 10%, at least 11%, at least 12%, at least 13%, at least 14%,
at least 15%, at least 16%, at least 17%, at least 18%, at least
19%, at least 20%, at least 21%, at least 22%, at least 23%, at
least 24%, at least 25%, at least 30%, at least 35%, at least 40%,
at least 45%, at least 50%, at least 60%, at least 70%, at least
80%, at least 90%, or at least 10% greater on a relative basis than
the corresponding vegetative plant part, or non-human organism or
part thereof or seed.
[0141] Also for Feature (i), the extent of increase in the level of
the one or more non-polar lipids and/or the total non-polar lipid
content may be at least 2-fold, at least 3-fold, at least 4-fold,
at least 5-fold, at least 6-fold, at least 7-fold, at least 8-fold,
at least 9-fold, at least 10-fold, or at least 12-fold, preferably
at least about 13-fold or at least about 15-fold greater on a
relative basis than the corresponding vegetative plant part, or
non-human organism or part thereof, or seed.
[0142] As a result of the increase in the level of the one or more
non-polar lipids and/or the total non-polar lipid content as
defined in Feature (i), the total non-polar lipid content of the
vegetative plant part, or non-human organism or part thereof, or
seed is preferably between 5% and 25%, between 7% and 25%, between
10%0 and 25%, between 12% and 25%, between 15% and 25%, between 7%
and 20%, between 10% and 20%, about 10%, about 11%, about 12%,
about 13%, about 14%, about 15%, about 16%, about 17%, about 18%,
about 20%, or about 22%, each as a percentage of dry weight or seed
weight.
[0143] For Feature (ii), in an embodiment, the non-human organism
is a plant, alga, or an organism suitable for fermentation such as
a yeast or other fungus, preferably an oleaginous fungus such as an
oleaginous yeast. The plant may be, or the vegetative plant part
may be from, for example, a plant which is Acrocomia aculeata
(macauba palm), Arabidopsis thaliana, Aracinis hypogaea (peanut),
Astrocaryum murumuru (murnunu), Astrocaryum vulgare (tucuma),
Attalea geraensis (Indaia-rateiro), Attalea humilis (American oil
palm), Attalea oleifera (andaia), Attalea phalerata (uricuri),
Attalea speciosa (babassu), Avena sativa (oats), Beta vulgaris
(sugar beet), Brassica sp. such as Brassica carinata, Brassica
juncea, Brassica napobrassica, Brassica napus (canola), Camelina
saliva (false flax), Cannabis saliva (hemp), Carthamus tinctorius
(safflower), Caryouar brasiliense (pequi), Cocos nucifera
(Coconut), Crambe abyssinica (Abyssinian kale), Cucumis melo
(melon), Elaeis guineensis (African palm), Glycine max (soybean),
Gossypium hirsutum (cotton), Helianthus sp. such as Helianthus
annuus (sunflower), Hordeum vulgare (barley), Jatropha curcas
(physic nut), Joannesia princeps (arara nut-tree), Lemna sp.
(duckweed) such as Lemna aequinoctialis, Lemna disperma, Lemna
ecuadoriensis, Lemna gibba (swollen duckweed), Lemna japonica,
Lemna minor, Lemna minuta, Lemna obscura, Lemna paucicostala, Lemna
perpusilla, Lemna tenera, Lemna trisulca, Lemna turionifera, Lemna
valdiviana, Lemna yungensis, Licania rigida (oiticica), Linum
usitatissimum (flax), Lupinus angustifolius (lupin), Mauritia
flexosa (buriti palm), Maximiliana maripa (inaja palm), Miscanthus
sp. such as Miscanthus x giganteus and Miscanthus sinensis,
Nicotiana sp. (tabacco) such as Nicotiana tabacum or Nicotiana
benthamiana, Oenocarpus bacaba (bacaba-do-azeite), Oenocarpus
bataua (pataui), Oenocarpus distichus (bacaba-de-leque), Oryza sp.
(rice) such as Oryza saliva and Oryza glaberrima, Panicum virgatum
(switchgrass), Paraqueiba paraensis (mari), Persea amencana
(avocado), Pongamia pinnata (Indian beech), Populus richocarpa,
Ricinus communis (castor), Saccharum sp. (sugarcane), Sesamum
indicum (sesame), Solanum tuberosum (potato), Sorghum sp. such as
Sorghum bicolor, Sorghum vulgare, Theobroma grandiforum (cupuassu),
Trifolium sp., Trithrinar brasiliensis (Brazilian needle palm),
Triticum sp. (wheat) such as Triticum aestivum and Zea mays (corn).
In an embodiment, the Brassica napus plant is of the variety
Westar. In an alternative embodiment, if the plant is Brassica
napus, it is of a variety or cultivar other than Westar. In an
embodiment, the plant is of a species other than Arabidopsis
thaliana. In another embodiment, the plant is of a species other
than Nicotiana tabacum. In another embodiment, the plant is of a
species other than Nicotiana benthamiana. In one embodiment, the
plant is a perennial, for example, a switchgrass. Each of the
features described for the plant of the second aspect can be
applied mutatis mutandis to the vegetative plant part of the first
aspect.
[0144] For Feature (iii), TAG, DAG, TAG and DAG, MAG, total
polyunsaturated fatty acid (PUFA), or a specific PUFA such as
eicosadienoic acid (EDA), arachidonic acid (ARA), alpha linolenic
acid (ALA), stearidonic acid (SDA), eicosatrienoic acid (ETE),
eicosatetraenoic acid (ETA), eicosapentaenoic acid (EPA),
docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), or a fatty
acid which comprises a hydroxyl group, an epoxy group, a
cyclopropane group, a double carbon-carbon bond, a triple
carbon-carbon bond, conjugated double bonds, a branched chain such
as a methylated or hydroxylated branched chain, or a combination of
two or more thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains, is/are increased
or decreased. The extent of the increase of TAG, DAG, TAG and DAG,
MAG, PUFA, specific PUFA, or fatty acid, is as defined in Feature
(i) above. In a preferred embodiment, the MAG is 2-MAG. Preferably,
DAG and/or TAG, more preferably the total of DAG and TAG, or MAG
and TAG, are increased. In an embodiment, TAG levels are increased
without increasing the MAG and/or DAG content.
[0145] Also for Feature (iii), in an embodiment, the total fatty
acid content and/or TAG content of the total non-polar lipid
content comprises (a) at least 2% more, preferably at least 5%
more, more preferably at least 7% more, most preferably at least
10% more, at least 15% more, at least 20% more, at least 25% more
oleic acid, or at least 30% more relative to the non-polar lipid(s)
in the corresponding vegetative plant part, or non-human organism
or part thereof, or seed lacking the one or more exogenous
polynucleotides. In an embodiment, the total fatty acid content in
the non-polar lipid(s) comprises (b) at least 2% less, preferably
at least 4% less, more preferably at least 7% less, at least 10%
less, at least 15% less, or at least 20% less palmitic acid
relative to the non-polar lipid(s) in the corresponding vegetative
plant part, or non-human organism or part thereof, or seed lacking
the one or more exogenous polynucleotides. In an embodiment, the
total fatty acid content of the total non-polar lipid content
comprises (c) at least 2% less, preferably at least 4% less, more
preferably at least 7% less, at least 10% less, or at least 15%
less ALA relative to the non-polar lipid(s) in the corresponding
vegetative plant part, or non-human organism or part thereof, or
seed lacking the one or more exogenous polynucleotides. In an
embodiment, the total fatty acid content of the total non-polar
lipid content comprises (d) at least 2% more, preferably at least
5% more, more preferably at least 7% more, most preferably at least
10% more, or at least 15% more, LA, relative to the non-polar
lipid(s) in the corresponding vegetative plant part, or non-human
organism or part thereof, or seed lacking the one or more exogenous
polynucleotides. Most preferably, the total fatty acid and/or TAG
content of the total non-polar lipid content has an increased oleic
acid level according to a figure defined in (a) and a decreased
palmitic acid content according to a figure defined in (b). In an
embodiment, the total sterol content is increased by at least 10%
relative to seedoil from a corresponding seed. In an embodiment,
the extracted lipid or oil comprises at least 10 ppm chlorophyll,
preferably at least 30 ppm chlorophyll. The chlorophyll may
subsequently be removed by de-colourising the extracted lipid or
oil.
[0146] In preferred embodiments, the one or more non-polar lipids
and/or the total non-polar lipid content is defined by the
combination of Features (i), (ii) and (iii), or Features (i) and
(ii), or Features (i) and (iii), or Features (ii) and (iii).
[0147] The process of the second aspect of the invention provides,
in an embodiment, that one or more or all of the following features
apply:
[0148] (i) the level of one or more non-polar lipids in the
vegetative plant part, or non-human organism or part thereof, or
seed is at least 0.5% greater on a weight basis than the level in a
corresponding vegetative plant part, non-human organism or part
thereof, or seed, respectively, lacking the one or more exogenous
polynucleotide(s), or preferably as further defined in Feature
(i),
[0149] (ii) the level of one or more non-polar lipids in the
vegetative plant part, non-human organism or part thereof, or seed
is at least 1% greater on a relative basis than in a corresponding
vegetative plant part, non-human organism or part thereof, or seed,
respectively, lacking the one or more exogenous polynucleotide(s),
or preferably as further defined in Feature (i),
[0150] (iii) the total non-polar lipid content in the vegetative
plant part, non-human organism or part thereof or seed is at least
0.5% greater on a weight basis than the level in a corresponding
vegetative plant part, non-human organism or part thereof, or seed,
respectively, lacking the one or more exogenous polynucleotide(s),
or preferably as further defined in Feature (i),
[0151] (iv) the total non-polar lipid content in the vegetative
plant part, non-human organism or part thereof, or seed is at least
1% greater on a relative basis than in a corresponding vegetative
plant part, non-human organism or part thereof, or seed,
respectively, lacking the one or more exogenous polynucleotide(s),
or preferably as further defined in Feature (i),
[0152] (v) the level of one or more non-polar lipids and/or the
total non-polar lipid content of the vegetative plant part,
non-human organism or part thereof, or seed, is at least 0.5%
greater on a weight basis and/or at least 1% greater on a relative
basis than a corresponding vegetative plant part, non-human
organism or a part thereof, or seed, respectively, which is lacking
the one or more exogenous polynucleotides and which comprises an
exogenous polynucleotide encoding an Arabidopsis thaliana DGAT1, or
preferably as further defined in Feature (i),
[0153] (vi) the TAG, DAG, TAG and DAG, or MAG content in the lipid
in the vegetative plant part, non-human organism or part thereof,
or seed, and/or in the extracted lipid therefrom, is at least 10%
greater on a relative basis than the TAG, DAG, TAG and DAG, or MAG
content in the lipid in a corresponding vegetative plant part,
non-human organism or a part thereof or seed lacking the one or
more exogenous polynucleotide(s), or a corresponding extracted
lipid therefrom, respectively, or preferably as further defined in
Feature (i), and
[0154] (vii) the total polyunsaturated fatty acid (PUFA) content in
the lipid in the vegetative plant part, non-human organism or part
thereof, or seed and/or in the extracted lipid therefrom, is
increased (e.g., in the presence of a MGAT) or decreased (e.g., in
the absence of a MGAT) relative to the total PUFA content in the
lipid in a corresponding vegetative plant part, non-human organism
or part thereof, or seed lacking the one or more exogenous
polynucleotide(s), or a corresponding extracted lipid therefrom,
respectively, or preferably as further defined in Feature (i) or
Feature (iii).
[0155] In an embodiment, the level of a PUFA in the vegetative
plant part, non-human organism or part thereof, or seed and/or the
extracted lipid therefrom, is increased relative to the level of
the PUFA in a corresponding vegetative plant part, non-human
organism or part thereof or seed, or a corresponding extracted
lipid therefrom, respectively, wherein the polyunsaturated fatty
acid is eicosadienoic acid, arachidonic acid (ARA), alpha linolenic
acid (ALA), stearidonic acid (SDA), eicosatrienoic acid (ETE),
eicosatetraenoic acid (ETA), eicosapentaenoic acid (EPA),
docosapentaenoic acid (DPA), docosahexaenoic acid (DHA), or a
combination of two of more thereof. Preferably, the extent of the
increase is as defined in Feature (i).
[0156] In an embodiment of the second aspect, the corresponding
vegetative plant part, or non-human organism or part thereof, or
seed is a non-transgenic vegetative plant part, or non-human
organism or part thereof; or seed, respectively. In a preferred
embodiment, the corresponding vegetative plant part, or non-human
organism or part thereof, or seed is of the same cultivar, strain
or variety but lacking the one or more exogenous polynucleotides.
In a further preferred embodiment, the corresponding vegetative
plant part, or non-human organism or part thereof, or seed is at
the same developmental stage, for example, flowering, as the
vegetative plant part, or non-human organism or part thereof, or
seed. In another embodiment, the vegetative plant parts are
harvested from about at the time of flowering to about the
beginning of senescence. In another embodiment, the seed is
harvested when the plants are at least about 1 month of age.
[0157] In an embodiment, part of the non-human organism is seed and
the total oil content, or the total fatty acid content, of the seed
is at least 0.5% to 25%, or at least 1.0% to 24%, greater on a
weight basis than a corresponding seed lacking the one or more
exogenous polynucleotides.
[0158] In an embodiment, the relative DAG content of the seedoil is
at least 10%, at least 10.5%, at least 11%, at least 11.5%, at
least 12%, at least 12.5%, at least 13%, at least 13.5%, at least
14%, at least 14.5%, at least 15%, at least 15.5%, at least 16%, at
least 16.5%, at least 17%, at least 17.5%, at least 18%, at least
18.5%, at least 19%, at least 19.5%, at least 20% greater on a
relative basis than of seedoil from a corresponding seed. In an
embodiment, the DAG content of the seed is increased by an amount
as defined in Feature (i) and the seed is from a genus and/or
species as defined in Feature (ii).
[0159] In an embodiment, the relative TAG content of the seed is at
least 5%, at least 5.5%, at least 6%, at least 6.5%, at least 7%,
at least 7.5%, at least 8%, at least 8.5%, at least 9%, at least
9.5%, at least 10%, or at least 11% greater on an absolute basis
relative to a corresponding seed. In an embodiment, the TAG content
of the seed is increased by an amount as defined in Feature (i) and
the seed is from a genus and/or species as defined in Feature
(ii).
[0160] In another embodiment, the part of the non-human organism is
a vegetative plant part and the TAG, DAG, TAG and DAG, or MAG
content of the vegetative plant part is at least 10%, at least 11%,
at least 12%, at least 13%, at least 14%, at least 15%, at least
16%, at least 17%, at least 18%, at least 19%, at least 20%, at
least 21%, at least 22%, at least 23%, at least 24%, at least 25%,
at least 30% at least 35%, at least 40%, at least 45%, at least
50%, at least 60%, at least 70%, at least 80%, at least 90%, or at
least 100% greater on a relative basis than the TAG, DAG, TAG and
DAG, or MAG content of a corresponding vegetative plant part
lacking the one or more exogenous polynucleotides. In a preferred
embodiment, the MAG is 2-MAG. In an embodiment, the TAG, DAG, TAG
and DAG, or MAG content of the vegetative plant part is determined
from the amount of these lipid components in the extractable lipid
of the vegetative plant part. In a further embodiment, the TAG,
DAG, TAG and DAG, or MAG content of the transgenic vegetative plant
part is increased by an amount as defined in Feature (i).
[0161] In an embodiment, at least 20% (mol %), at least 22% (mol
%), at least 30% (mol %), at least 40% (mol %), at least 50% (mol
%) or at least 60% (mol %), preferably at least 65% (mol %), more
preferably at least 66% (mol %), at least 67% (mol %), at least 68%
(mol %), at least 69% (mol %) or at least 70% (mol %) of the fatty
acid content of the total non-polar lipid content of the vegetative
plant part, non-human organism or part thereof, or seed, or of the
lipid or oil extracted therefrom, preferably of the TAG fraction,
is oleic acid. Such high oleic contents are preferred for use in
biodiesel applications.
[0162] In another embodiment, the PUFA content of the vegetative
plant part, or non-human organism or part thereof or seed is
increased (e.g., in the presence of a MGAT) or decreased (e.g., in
the absence of a MGAT) when compared to the corresponding
vegetative plant part, or non-human organism or part thereof, or
seed. In this context, the PUFA content includes both esterified
PUFA (including TAG, DAG, etc.) and non-esterified PUFA. In an
embodiment, the PUFA content of the vegetative plant part, or
non-human organism or part thereof, or seed is preferably
determined from the amount of PUFA in the extractable lipid of the
vegetative plant part, or non-human organism or part thereof, or
seed. The extent of the increase in PUFA content may be as defined
in Feature (i). The PUFA content may comprise EDA, ARA, ALA, SDA,
ETE, ETA, EPA, DPA, DHA, or a combination of two of more
thereof.
[0163] In another embodiment, the level of a PUFA in the vegetative
plant part, non-human organism or part thereof, or seed, or the
lipid or oil extracted therefrom is increased or decreased when
compared to the corresponding vegetative plant part, non-human
organism or part thereof, or seed, or the lipid or oil extracted
therefrom. The PUFA may be EDA, ARA, ALA, SDA, ETE, ETA, EPA, DPA,
DHA, or a combination of two of more thereof. The extent of the
increase in the PUFA may be as defined in Feature (i).
[0164] In another embodiment, the level of a fatty acid in the
extracted lipid or oil is increased when compared to the lipid
extracted from the corresponding vegetative plant part, or
non-human organism or part thereof, or seed and wherein the fatty
acid comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains. The extent of the
increase in the fatty acid may be as defined in Feature (i).
[0165] In an embodiment, the level of the one or more non-polar
lipids (such as TAG, DAG, TAG and DAG, MAG, PUFA, or a specific
PUFA, or a specific fatty acid) and/or the total non-polar lipid
content is determinable by analysis by using gas chromatography of
fatty acid methyl esters obtained from the extracted lipid.
Alternate methods for determining any of these contents are known
in the art, and include methods which do not require extraction of
lipid from the organism or part thereof, for example, analysis by
near infrared (NIR) or nuclear magnetic resonance (NMR).
[0166] In a further embodiment, the level of the one or more
non-polar lipids and/or the total non-polar lipid content of the
vegetative plant part, or non-human organism or part thereof or
seed is at least 0.5% greater on a dry weight or seed weight basis
and/or at least 1% greater on a relative basis, preferably at least
1% or 2% greater on a dry weight or seed weight basis, than a
corresponding vegetative plant part, or non-human organism or a
part thereof, or seed lacking the one or more exogenous
polynucleotides but comprising an exogenous polynucleotide encoding
an Arabidopsis thaliana DGAT1 (SEQ ID NO:83).
[0167] In yet a further embodiment, the vegetative plant part or
the non-human organism or part thereof, or seed further comprises
(i) one or more introduced mutations, and/or (ii) an exogenous
polynucleotide which down-regulate the production and/or activity
of an endogenous enzyme of the vegetative plant part or the
non-human organism or part thereof, the endogenous enzyme being
selected from a fatty acid acyltransferase such as DGAT, sn-1
glycerol-3-phosphate acyltransferase (sn-1 GPAT),
1-acyl-glycerol-3-phosphate acyltransferase (LPAAT),
acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT),
phosphatidic acid phosphatase (PAP), an enzyme involved in starch
biosynthesis such as (ADP)-glucose pyrophosphorylase (AGPase), a
fatty acid desaturase such as a .DELTA.12 fatty acid desaturase
(FAD2), a polypeptide involved in the degradation of lipid and/or
which reduces lipid content such as a lipase such as CGi58
polypeptide or SUGAR-DEPENDENT1 triacylglycerol lipase, or a
combination of two or more thereof. In an alternative embodiment,
the vegetative plant part or the non-human organism or part thereof
does not comprise (i) above, or does not comprise (ii) above, or
does not comprise (i) above and does not comprise (ii) above. In an
embodiment, the exogenous polynucleotide which down-regulates the
production of AGPase is not the polynucleotide disclosed in Sanjaya
et al. (2011). In an embodiment, the exogenous polynucleotides in
the vegetative plant part or the non-human organism or part
thereof, or seed does not consist of an exogenous polynucleotide
encoding a WRI1 and an exogenous polynucleotide encoding an RNA
molecule which inhibits expression of a gene encoding an
AGPase.
[0168] In the process of either the first or second aspects, the
vegetative plant part, or non-human organism or part thereof, or
seed, or the extracted lipid or oil, is further defined in
preferred embodiments. Therefore, in an embodiment one or more or
all of the following features apply
[0169] (i) oleic acid comprises at least 20% (mol %), at least 22%
(mol %), at least 30% (mol %), at least 40% (mol %), at least 50%
(mol %), or at least 60% (mol %), preferably at least 65% (mol %)
or at least 66% (mol %) of the total fatty acid content in the
non-polar lipid or oil in the vegetative plant part, non-human
organism or part thereof, or seed,
[0170] ii) oleic acid comprises at least 20% (mol %), at least 22%
(mol %), at least 30% (mol %), at least 40% (mol %), at least 50%
(mol %), or at least 60% (mol %), preferably at least 65% (mol %)
or at least 66% (mol %) of the total fatty acid content in the
extracted lipid or oil,
[0171] (iii) the non-polar lipid or oil in the vegetative plant
part, non-human organism or part thereof, or seed comprises a fatty
acid which comprises a hydroxyl group, an epoxy group, a
cyclopropane group, a double carbon-carbon bond, a triple
carbon-carbon bond, conjugated double bonds, a branched chain such
as a methylated or hydroxylated branched chain, or a combination of
two or more thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains, and
[0172] (iv) the extracted lipid or oil comprises a fatty acid which
comprises a hydroxyl group, an epoxy group, a cyclopropane group, a
double carbon-carbon bond, a triple carbon-carbon bond, conjugated
double bonds, a branched chain such as a methylated or hydroxylated
branched chain, or a combination of two or more thereof, or any of
two, three, four, five or six of the aforementioned groups, bonds
or branched chains. The fatty acid composition in this embodiment
is measured prior to any modification of the fatty acid
composition, such as, for example, by fractionating the extracted
lipid or oil to alter the fatty acid composition. In preferred
embodiments, the extent of the increase is as defined in Feature
(i).
[0173] In an embodiment, the level of a lipid in the vegetative
plant part, non-human organism or part thereof, or seed and/or in
the extracted lipid or oil is determinable by analysis by using gas
chromatography of fatty acid methyl esters prepared from the
extracted lipid or oil. The method of analysis is preferably as
described in Example 1 herein.
[0174] Again with respect to either the first or second aspects,
the invention provides for one or more exogenous polynucleotides in
the vegetative plant part, or non-human organism or part thereof,
or seed used in the process. Therefore, in an embodiment, the
vegetative plant part, or the non-human organism or part thereof;
or the seed comprises a first exogenous polynucleotide which
encodes an RNA or preferably a transcription factor polypeptide
that increases the expression of one or more glycolytic or fatty
acid biosynthetic genes in a vegetative plant part, or a non-human
organism or a part thereof, or a seed, respectively, and a second
exogenous polynucleotide which encodes an RNA or a polypeptide
involved in biosynthesis of one or more non-polar lipids, wherein
the first and second exogenous polynucleotides are each operably
linked to a promoter which is capable of directing expression of
the polynucleotide in a vegetative plant part, or a non-human
organism or a part thereof, or a seed, respectively. That is, the
first and second exogenous polynucleotides encode different factors
which together provide for the increase in the non-polar lipid
content in the vegetative plant part, or the non-human organism or
part thereof, or the seed.
[0175] The increase is preferably additive, more preferably
synergistic, relative to the presence of either the first or second
exogenous polynucleotide alone. The factors encoded by the first
and second polynucleotides operate by different mechanisms.
[0176] Preferably, the transcription factor polypeptide increases
the availability of substrates for non-polar lipid synthesis, such
as, for example, increasing glycerol-3-phosphate and/or fatty acids
preferably in the form of acyl-CoA, by increasing expression of
genes, for example at least 5 or at least 8 genes, involved in
glycolysis or fatty acid biosynthesis (such as, but not limited to,
one or more of ACCase, sucrose transporters (SuSy, cell wall
invertases), ketoacyl synthase (KAS), phosphofructokinase (PFK),
pyruvate kinase (PK) (for example, (At5g52920, At3g22960), pyruvate
dehydrogenase, hexose transporters (for example, GPT2 and PPT1),
cytosolic fructokinase, cytosolic phosphoglycerate mutase,
enoyl-ACP reductase (At2g05990), and phosphoglycerate mutase
(At1g22170)) preferably more than one gene for each category. In an
embodiment, the first exogenous polynucleotide encodes a Wrinkled 1
(WRI1) transcription factor, a Leafy Cotyledon 1 (Lec1)
transcription factor, a Leafy Cotyledon 2 (LEC2) transcription
factor, a Fus3 transcription factor, an ABI3 transcription factor,
a Dof4 transcription factor, a BABY BOOM (BBM) transcription factor
or a Dof11 transcription factor. In one embodiment, the LEC2 is not
an Arabidopsis LEC2. As part of this embodiment, or separately, the
second exogenous polynucleotide may encode a polypeptide having a
fatty acid acyltransferase activity, for example, monoacylglycerol
acyltransferase (MGAT) activity and/or diacylglycerol
acyliransferase (DGAT) activity, or glycerol-3-phosphate
acyltransferase (GPAT) activity. In one embodiment, the DGAT is not
an Arabidopsis DGAT.
[0177] In a preferred embodiment, the vegetative plant part, or
non-human organism or a part thereof, or the seed, of the first or
second aspects of the invention comprises two or more exogenous
polynucleotide(s), one of which encodes a transcription factor
polypeptide that increases the expression of one or more glycolytic
or fatty acid biosynthetic genes in the vegetative plant part, or
non-human organism or a part thereof, or seed such as a Wrinkled 1
(WRI1) transcription factor, and a second of which encodes a
polypeptide involved in biosynthesis of one or more non-polar
lipids such as a DGAT.
[0178] In an embodiment, the vegetative plant part, non-human
organism or a part thereof, or the seed of the first or second
aspects of the invention may further comprise a third, or more,
exogenous polynucleotide(s). The third, or more, exogenous
polynucleotide(s) may encode one or more or any combination of:
[0179] i) a further RNA or transcription factor polypeptide that
increases the expression of one or more glycolytic or fatty acid
biosynthetic genes in a non-human organism or a part thereof (for
example, if the first exogenous polynucleotide encodes a Wrinkled 1
(WRI1) transcription factor, the third exogenous polynucleotide may
encode a LEC2 or BBM transcription factor (preferably, LEC2 or BBM
expression controlled by an inducible promoter or a promoter which
does not result in high transgene expression levels),
[0180] ii) a further RNA or polypeptide involved in biosynthesis of
one or more non-polar lipids (for example, if the second exogenous
polynucleotide encodes a DGAT, the third exogenous polynucleotide
may encode a MGAT or GPAT, or two further exogenous polynucleotides
may be present encoding an MGAT and a GPAT),
[0181] iii) a polypeptide that stabilizes the one or more non-polar
lipids, preferably an oleosin, such as a polyoleosin or a caleosin,
more preferably a polyoleosin,
[0182] iv) an RNA molecule which inhibits expression of a gene
encoding a polypeptide involved in starch biosynthesis such as a
AGPase polypeptide,
[0183] v) an RNA molecule which inhibits expression of a gene
encoding a polypeptide involved in the degradation of lipid and/or
which reduces lipid content such as a lipase such as CGi58
polypeptide or SUGAR-DEPENDENT1 triacylglycerol lipase, or
[0184] vi) a silencing suppressor polypeptide,
wherein the third, or more, exogenous polynucleotide(s) is operably
linked to a promoter which is capable of directing expression of
the polynucleotide(s) in a vegetative plant part, or a non-human
organism or a part thereof, or a seed, respectively.
[0185] A number of specific combinations of genes are shown herein
to be effective for increasing non-polar lipid contents. Therefore,
regarding the process of either the first or second aspects of the
invention, in an embodiment, the vegetative plant part, or the
non-human organism or part thereof; or the seed comprises one or
more exogenous polynucleotide(s) which encode:
[0186] i) a Wrinkled 1 (WRI1) transcription factor and a DGAT,
[0187] ii) a WRI1 transcription factor and a DGAT and an
Oleosin,
[0188] iii) a WRI1 transcription factor, a DGAT, a MGAT and an
Oleosin,
[0189] iv) a monoacylglycerol acyltransferase (MGAT),
[0190] v) a diacylglycerol acyltransferase 2 (DGAT2),
[0191] vi) a MGAT and a glycerol-3-phosphate acyltransferase
(GPAT),
[0192] vii) a MGAT and a DGAT,
[0193] viii) a MGAT, a GPAT and a DGAT,
[0194] ix) a WRI1 transcription factor and a MGAT,
[0195] x) a WRI1 transcription factor, a DGAT and a MGAT,
[0196] xi) a WRI1 transcription factor, a DGAT, a MGAT, an Oleosin
and a GPAT,
[0197] xii) a DGAT and an Oleosin, or
[0198] xiii) a MGAT and an Oleosin, and
[0199] xiv) optionally, a silencing suppressor polypeptide,
[0200] wherein each of the one or more exogenous polynucleotide(s)
is operably linked to a promoter which is capable of directing
expression of the polynucleotide in a vegetative plant part, or a
non-human organism or part thereof, or seed, respectively.
Preferably the one or more exogenous polynucleotides are stably
integrated into the genome of the vegetative plant part, or the
non-human organism or part thereof, or the seed, and more
preferably are present in a homozygous state. The polynucleotide
may encode an enzyme having an amino acid sequence which is the
same as a sequence of a naturally occurring enzyme of; for example,
plant, yeast or animal origin. Further, the polynucleotide may
encode an enzyme having one or more conservative mutations when
compared to the naturally occurring enzyme.
[0201] In an embodiment,
[0202] (i) the GPAT also has phosphatase activity to produce MAG,
such as a polypeptide having an amino acid sequence of Arabidopsis
GPAT4 or GPAT6, and/or
[0203] (ii) the DGAT is a DGAT1 or a DGAT2, and/or
[0204] (iii) the MGAT is an MGAT1 or an MGAT2.
[0205] In a preferred embodiment, the vegetative plant part, the
non-human organism or part thereof; or the seed comprises a first
exogenous polynucleotide encoding a WRI1 and a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1.
[0206] In another preferred embodiment, the vegetative plant part,
the non-human organism or part thereof, or the seed comprises a
first exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, and a third
exogenous polynucleotide encoding an oleosin.
[0207] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding an MGAT, preferably an MGAT2.
[0208] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding LEC2 or BBM.
[0209] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an MGAT, preferably an MGAT2, and a fifth
exogenous polynucleotide encoding LEC2 or BBM.
[0210] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding an RNA molecule which inhibits
expression of a gene encoding a lipase such as CGi58
polypeptide.
[0211] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, and a
fifth exogenous polynucleotide encoding LEC2 or BBM.
[0212] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, and a
fifth exogenous polynucleotide encoding an MGAT, preferably an
MGAT2.
[0213] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, a fifth
exogenous polynucleotide encoding an MGAT, preferably an MGAT2, and
a sixth exogenous polynucleotide encoding LEC2 or BBM.
[0214] In an embodiment, the seed comprises a first exogenous
polynucleotide encoding a WRI1, a second exogenous polynucleotide
encoding a DGAT, preferably a DGAT1, a third exogenous
polynucleotide encoding an oleosin, and a fourth exogenous
polynucleotide encoding an MGAT, preferably an MGAT2. Preferably,
the seed further comprises a fifth exogenous polynucleotide
encoding a GPAT.
[0215] Where relevant, instead of a polynucleotide encoding an RNA
molecule which inhibits expression of a gene encoding a lipase such
as a CGi58 polypeptide, the vegetative plant part, the non-human
organism or part thereof, or the seed has one or more introduced
mutations in the lipase gene such as a CGi58 gene which confers
reduced levels of the lipase polypeptide when compared to a
corresponding vegetative plant part, non-human organism or part
thereof, or seed lacking the mutation.
[0216] In a preferred embodiment, the exogenous polynucleotides
encoding the DGAT and oleosin are operably linked to a constitutive
promoter, or a promoter active in green tissues of a plant at least
before and up until flowering, which is capable of directing
expression of the polynucleotides in the vegetative plant part, the
non-human organism or part thereof, or the seed. In a further
preferred embodiment, the exogenous polynucleotide encoding WRI1,
and RNA molecule which inhibits expression of a gene encoding a
lipase such as a CGi58 polypeptide, is operably linked to a
constitutive promoter, a promoter active in green tissues of a
plant at least before and up until flowering, or an inducible
promoter, which is capable of directing expression of the
polynucleotides in the vegetative plant part, the non-human
organism or part thereof or the seed. In yet a further preferred
embodiment, the exogenous polynucleotides encoding LEC2, BBM and/or
MGAT2 are operably linked to an inducible promoter which is capable
of directing expression of the polynucleotides in the vegetative
plant part, the non-human organism or part thereof, or the
seed.
[0217] In each of the above embodiments, the polynucleotides may be
provided as separate molecules or may be provided as a contiguous
single molecule, such as on a single T-DNA molecule. In an
embodiment, the orientation of transcription of at least one gene
on the T-DNA molecule is opposite to the orientation of
transcription of at least one other gene on the T-DNA molecule.
[0218] In each of the above embodiments, the total non-polar lipid
content of the vegetative plant part, or non-human organism or part
thereof, or the seed, preferably a plant leaf or part thereof, stem
or tuber, is at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, or more preferably at least about 15% (w/w dry weight).
In a further preferred embodiment, the total non-polar lipid
content is between 5% and 25%, between 7% and 25%, between 10% and
25%, between 12% and 25%, between 15% and 25%, between 7% and 20%,
between 10% and 20%, between 10% and 15%, between 15% and 20%,
between 20% and 25%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
or about 22%, each as a percentage of dry weight or seed weight. In
a particularly preferred embodiment, the vegetative plant part is a
leaf (or leaves) or a portion thereof. In a more preferred
embodiment, the vegetative plant part is a leaf portion having a
surface area of at least 1 cm.sup.2.
[0219] Furthermore, in each of the above embodiments, the total TAG
content of the vegetative plant part, or non-human organism or part
thereof, or the seed, preferably a plant leaf or part thereof, stem
or tuber, is at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, more preferably at least about 15%, or more preferably
at least about 17% (w/w dry weight). In a further preferred
embodiment, the total TAG content is between 5% and 30%, between 7%
and 30%, between 10% and 30%, between 12% and 30%, between 15% and
30%, between 7% and 30%, between 10% and 30%, between 20% and 28%,
between 18% and 25%, between 22% and 30%, about 100, about 11%,
about 12%, about 13%, about 14%, about 15%, about 16%, about 17%,
about 18%, about 20%, or about 22%, each as a percentage of dry
weight or seed weight. In a particularly preferred embodiment, the
vegetative plant part is a leaf (or leaves) or a portion thereof.
In a more preferred embodiment, the vegetative plant part is a leaf
portion having a surface area of at least 1 cm.sup.2.
[0220] Furthermore, in each of the above embodiments, the total
lipid content of the vegetative plant part, or non-human organism
or part thereof, or the seed, preferably a plant leaf or part
thereof, stem or tuber, is at least about 3%, more preferably at
least about 5%, preferably at least about 7%, more preferably at
least about 10%, more preferably at least about 11%, more
preferably at least about 12%, more preferably at least about 13%,
more preferably at least about 14%, more preferably at least about
15%, more preferably at least about 17% (w/w dry weight), more
preferably at least about 20%, more preferably at least about 25%.
In a further preferred embodiment, the total lipid content is
between 5% and 35%, between 7% and 35%, between 10% and 35%,
between 12% and 35%, between 15% and 35%, between 7% and 35%,
between 10% and 20%, between 18% and 28%, between 20% and 28%,
between 22% and 28%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
about 22%, or about 25%, each as a percentage of dry weight.
Typically, the total lipid content of the vegetative plant part, or
non-human organism or part thereof is about 2-3% higher than the
non-polar lipid content. In a particularly preferred embodiment,
the vegetative plant part is a leaf (or leaves) or a portion
thereof. In a more preferred embodiment, the vegetative plant part
is a leaf portion having a surface area of at least 1 cm.sup.2.
[0221] In an embodiment, the vegetative plant part, the non-human
organism or part thereof or the seed, preferably the vegetative
plant part, comprises a first exogenous polynucleotide encoding a
WRI1, a second exogenous polynucleotide encoding a DGAT, preferably
a DGAT1, a third exogenous polynucleotide encoding an MGAT,
preferably an MGAT2, and a fourth exogenous polynucleotide encoding
an oleosin, wherein the vegetative plant part, non-human organism
or part thereof, or seed has one or more or all of the following
features:
[0222] i) a total lipid content of at least 8%, at least 10%, at
least 12%, at least 14%, or at least 15.5% (% weight),
[0223] ii) at least a 3 fold, at least a 5 fold, at least a 7 fold,
at least an 8 fold, or least a fold, at higher total lipid content
in the vegetative plant part or non-human organism relative to a
corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0224] iii) a total TAG content of at least 5%, at least 6%, at
least 6.5% or at least 7% (% weight of dry weight or seed
weight),
[0225] iv) at least a 40 fold, at least a 50 fold, at least a 60
fold, or at least a 70 fold, or at least a 100 fold, higher total
TAG content relative to a corresponding vegetative plant part or
non-human organism lacking the exogenous polynucleotides,
[0226] v) oleic acid comprises at least 15%, at least 19% or at
least 22% (% weight) of the fatty acids in TAG,
[0227] vi) at least a 10 fold, at least a 15 fold or at least a 17
fold higher level of oleic acid in TAG relative to a corresponding
vegetative plant part or non-human organism lacking the exogenous
polynucleotides,
[0228] vii) palmitic acid comprises at least 20%, at least 25%, at
least 30% or at least 33% (% weight) of the fatty acids in TAG,
[0229] viii) at least a 1.5 fold higher level of palmitic acid in
TAG relative to a corresponding vegetative plant part or non-human
organism lacking the exogenous polynucleotides,
[0230] ix) linoleic acid comprises at least 22%, at least 25%, at
least 30% or at least 34% (% weight) of the fatty acids in TAG,
[0231] x) .alpha.-linolenic acid comprises less than 20%, less than
15%, less than 11% or less than 8% (% weight) of the fatty acids in
TAG, and
[0232] xi) at least a 5 fold, or at least an 8 fold, lower level of
.alpha.-linolenic acid in TAG relative to a corresponding
vegetative plant part or non human organism lacking the exogenous
polynucleotides. In this embodiment, preferably the vegetative
plant part at least has feature(s), i), ii) iii), iv), i) and ii),
i) and iii), i) and iv), i) to iii), i), iii) and iv), i) to iv),
ii) and iii), ii) and iv), ii) to iv), or iii) and iv). In an
embodiment, % dry weight is % leaf dry weight.
[0233] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed, preferably the
vegetative plant part, comprises a first exogenous polynucleotide
encoding a WRI1, a second exogenous polynucleotide encoding a DGAT,
preferably a DGAT1, a third exogenous polynucleotide encoding an
oleosin, wherein the vegetative plant part, non-human organism or
part thereof; or seed has one or more or all of the following
features:
[0234] i) a total TAG content of at least 10%, at least 12.5%, at
least 15% or at least 17% (% weight of dry weight or seed
weight),
[0235] ii) at least a 40 fold, at least a 50 fold, at least a 60
fold, or at least a 70 fold, or at least a 100 fold, higher total
TAG content in the vegetative plant part or non-human organism
relative to a corresponding vegetative plant part or non human
organism lacking the exogenous polynucleotides,
[0236] iii) oleic acid comprises at least 19%, at least 22%, or at
least 25% (% weight) of the fatty acids in TAG,
[0237] iv) at least a 10 fold, at least a 15 fold, at least a 17
fold, or at least a 19 fold, higher level of oleic acid in TAG in
the vegetative plant part or non-human organism relative to a
corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0238] v) palmitic acid comprises at least 20%, at least 25%, or at
least 28% (% weight) of the fatty acids in TAG,
[0239] vi) at least a 1.25 fold higher level of palmitic acid in
TAG in the vegetative plant part or non-human organism relative to
a corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0240] vii) linoleic acid comprises at least 15%, or at least 20%,
(% weight) of the fatty acids in TAG,
[0241] viii) .alpha.-linolenic acid comprises less than 15%, less
than 11% or less than 8% (% weight) of the fatty acids in TAG,
and
[0242] ix) at least a 5 fold, or at least an 8 fold, lower level of
.alpha.-linolenic acid in TAG in the vegetative plant part or
non-human organism relative to a corresponding vegetative plant
part or non-human organism lacking the exogenous polynucleotides.
In this embodiment, preferably the vegetative plant part at least
has feature(s), i), ii), or i) and ii). In an embodiment, % dry
weight is % leaf dry weight
[0243] Preferably, the defined features for the two above
embodiments are as at the flowering stage of the plant.
[0244] In an alternate embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed consists of one or
more exogenous polynucleotides encoding a DGAT1 and a LEC2.
[0245] In a preferred embodiment, the exogenous polynucleotide
encoding WRI1 comprises one or more of the following:
[0246] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:231 to 278,
[0247] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:279 to
337, or a biologically active fragment thereof,
[0248] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0249] iv) nucleotides which hybridize to any one of i) to iii)
under stringent conditions.
[0250] In a preferred embodiment, the exogenous polynucleotide
encoding DGAT comprises one or more of the following:
[0251] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:204 to 211, 338 to 346,
[0252] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:83, 212
to 219, 347 to 355, or a biologically active fragment thereof;
[0253] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0254] iv) a polynucleotide which hybridizes to any one of i) to
iii) under stringent conditions.
[0255] In another preferred embodiment, the exogenous
polynucleotide encoding MGAT comprises one or more of the
following:
[0256] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:1 to 44,
[0257] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:45 to
82, or a biologically active fragment thereof,
[0258] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0259] iv) a polynucleotide which hybridizes to any one of i) to
iii) under stringent conditions.
[0260] In another preferred embodiment, the exogenous
polynucleotide encoding GPAT comprises one or more of the
following:
[0261] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:84 to 143,
[0262] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs: 144 to
203, or a biologically active fragment thereof,
[0263] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0264] iv) a polynucleotide which hybridizes to any one of i) to
iii) under stringent conditions.
[0265] In another preferred embodiment, the exogenous
polynucleotide encoding DGAT2 comprises one or more of the
following:
[0266] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:204 to 211,
[0267] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:212 to
219, or a biologically active fragment thereof,
[0268] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0269] iv) a polynucleotide which hybridizes to any one of i) to
iii) under stringent conditions.
[0270] In another preferred embodiment, the exogenous
polynucleotide encoding an oleosin comprises one or more of the
following:
[0271] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:389 to 408,
[0272] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:362 to
388, or a biologically active fragment thereof,
[0273] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0274] iv) a sequence of nucleotides which hybridizes to any one of
i) to iii) under stringent conditions.
[0275] In an embodiment, the CGi58 polypeptide comprises one or
more of the following:
[0276] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:422 to 428,
[0277] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:429 to
436, or a biologically active fragment thereof,
[0278] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0279] iv) a sequence of nucleotides which hybridizes to any one of
i) to iii) under stringent conditions.
[0280] In another embodiment, the exogenous polynucleotide encoding
LEC2 comprises one or more of the following:
[0281] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:437 to 439,
[0282] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:442 to
444, or a biologically active fragment thereof,
[0283] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0284] iv) a sequence of nucleotides which hybridizes to any one of
i) to iii) under stringent conditions.
[0285] In a further embodiment, the exogenous polynucleotide
encoding BBM comprises one or more of the following:
[0286] i) nucleotides whose sequence is set forth as any one of SEQ
ID NOs:440 or 441
[0287] ii) nucleotides encoding a polypeptide comprising amino
acids whose sequence is set forth as any one of SEQ ID NOs:445 or
446, or a biologically active fragment thereof,
[0288] iii) nucleotides whose sequence is at least 30% identical to
i) or ii), and
[0289] iv) a sequence of nucleotides which hybridizes to any one of
i) to iii) under stringent conditions.
[0290] Clearly, sequences preferred in one embodiment can be
combined with sequences preferred in another embodiment and more
advantageously further combined with a sequence preferred in yet
another embodiment.
[0291] In one embodiment, the one or more exogenous polynucleotides
encode a mutant MGAT and/or DGAT and/or GPAT. For example, the one
or more exogenous polynucleotides may encode a MGAT and/or DGAT
and/or GPAT having one, or more than one, conservative amino acid
substitutions as exemplified in Table 1 relative to a wildtype MGAT
and/or DGAT and/or GPAT as defined by a SEQ ID NO herein.
Preferably the mutant polypeptide has an equivalent or greater
activity relative to the non-mutant polypeptide.
[0292] In an embodiment, the vegetative plant part, non-human
organism or part thereof or seed comprises a first exogenous
polynucleotide that encodes a MGAT and a second exogenous
polynucleotide that encodes a GPAT. The first and second
polynucleotides may be provided as separate molecules or may be
provided as a contiguous single molecule, such as on a single T-DNA
molecule. In an embodiment, the orientation of transcription of at
least one gene on the T-DNA molecule is opposite to the orientation
of transcription of at least one other gene on the T-DNA molecule.
In a preferred embodiment, the GPAT is a GPAT having phosphatase
activity such as an Arabidopsis GPAT4 or GPAT6. The GPAT having
phosphatase activity acts to catalyze the formation of MAG from
G-3-P (i.e., acylates G-3-P to form LPA and subsequently removes a
phosphate group to form MAG) in the non-human organism or part
thereof. The MGAT then acts to catalyze the formation of DAG in the
non-human organism or part thereof by acylating the MAG with an
acyl group derived from fatty acyl-CoA. The MGAT such as A.
thaliana MGAT1 may also act to catalyze the formation of TAG in the
non-human organism or part thereof if it also has DGAT
activity.
[0293] The vegetative plant part, non-human organism or part
thereof or seed may comprise a third exogenous polynucleotide
encoding, for example, a DGAT. The first, second and third
polynucleotides may be provided as separate molecules or may be
provided as a contiguous single molecule, such as on a single T-DNA
molecule. The DGAT acts to catalyse the formation of TAG in the
transgenic vegetative plant part, non-human organism or part
thereof, or seed by acylating the DAG (preferably produced by the
MGAT pathway) with an acyl group derived from fatty acyl-CoA. In an
embodiment, the orientation of transcription of at least one gene
on the T-DNA molecule is opposite to the orientation of
transcription of at least one other gene on the T-DNA molecule.
[0294] In another embodiment, the vegetative plant part, non-human
organism or part thereof, or seed comprises a first exogenous
polynucleotide that encodes a MGAT and a second exogenous
polynucleotide that encodes a DGAT. The first and second
polynucleotides may be provided as separate molecules or may be
provided as a contiguous single molecule, such as on a single T-DNA
molecule. In an embodiment, the orientation of transcription of at
least one gene on the T-DNA molecule is opposite to the orientation
of transcription of at least one other gene on the T-DNA molecule.
The vegetative plant part, non-human organism or part thereof, or
seed may comprise a third exogenous polynucleotide encoding, for
example, a GPAT, preferably a GPAT having phosphatase activity such
as an Arabidopsis GPAT4 or GPAT6. The first, second and third
polynucleotides may be provided as separate molecules or may be
provided as a contiguous single molecule.
[0295] Furthermore, an endogenous gene activity in the plant,
vegetative plant part, or the non-human organism or part thereof;
or the seed may be down-regulated. Therefore, in an embodiment, the
vegetative plant part, the non-human organism or part thereof, or
the seed comprises one or more of:
[0296] (i) one or more introduced mutations in a gene which encodes
an endogenous enzyme of the plant, vegetative plant part, non-human
organism or part thereof, or seed, respectively, or
[0297] (ii) an exogenous polynucleotide which down-regulates the
production and/or activity of an endogenous enzyme of the plant,
vegetative plant part, non-human organism or part thereof, or seed,
respectively,
wherein each endogenous enzyme is selected from the group
consisting of a fatty acid acyltransferase such as DGAT, an sn-1
glycerol-3-phosphate acyltransferase (sn-1 GPAT), a
1-acyl-glycerol-3-phosphate acyliransferase (LPAAT), an
acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT), a
phosphatidic acid phosphatase (PAP), an enzyme involved in starch
biosynthesis such as (ADP)-glucose pyrophosphorylase (AGPase), a
fatty acid desaturase such as a .DELTA.12 fatty acid desaturase
(FAD2), a polypeptide involved in the degradation of lipid and/or
which reduces lipid content such as a lipase such as a CGi58
polypeptide or SUGAR-DEPENDENT1 triacylglycerol lipase, or a
combination of two or more thereof. In an embodiment, the exogenous
polynucleotide is selected from the group consisting of an
antisense polynucleotide, a sense polynucleotide, a catalytic
polynucleotide, a microRNA, a polynucleotide which encodes a
polypeptide which binds the endogenous enzyme, a double stranded
RNA molecule or a processed RNA molecule derived therefrom. In an
embodiment, the exogenous polynucleotide which down-regulates the
production of AGPase is not the polynucleotide disclosed in Sanjaya
et al. (2011). In an embodiment, the exogenous polynucleotides in
the vegetative plant part or the non-human organism or part
thereof, or seed does not consist of an exogenous polynucleotide
encoding a WRI1 and an exogenous polynucleotide encoding an RNA
molecule which inhibits expression of a gene encoding an
AGPase.
[0298] Increasing the level of non-polar lipids is important for
applications involving particular fatty acids. Therefore, in an
embodiment, the total non-polar lipid, the extracted lipid or oil
comprises:
[0299] (i) non-polar lipid which is TAG, DAG, TAG and DAG, or MAG,
and
[0300] (ii) a specific PUFA which is EDA, ARA, SDA, ETE, ETA, EPA,
DPA, DHA, the specific PUFA being at a level of at least 1% of the
total fatty acid content in the non-polar lipid, or a combination
of two or more of the specific PUFA, or
[0301] (iii) a fatty acid which is present at a level of at least
1% of the total fatty acid content in the non-polar lipid and which
comprises a hydroxyl group, an epoxy group, a cyclopropane group, a
double carbon-carbon bond, a triple carbon-carbon bond, conjugated
double bonds, a branched chain such as a methylated or hydroxylated
branched chain, or a combination of two or more thereof or any of
two, three, four, five or six of the aforementioned groups, bonds
or branched chains.
[0302] In a third aspect, the invention provides non-human
organisms, preferably plants, or parts thereof such as vegetative
plant parts or seed, which are useful in the processes of the first
and second aspects or in further aspects described hereafter. Each
of the features in the embodiments described for the first and
second aspects can be applied mutatis mutandis to the non-human
organisms, preferably plants, or parts thereof such as vegetative
plant parts or seed of the third aspect. Particular embodiments are
emphasized as follows.
[0303] In an embodiment of the third aspect, the present invention
provides a non-human organism or a part thereof, wherein the
non-human organism or part thereof has a total non-polar lipid
content of at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, or more preferably at least about 15% (w/w dry weight or
seed weight), wherein one or more or all of the following features
apply:
[0304] (a) the non-human organism or a part thereof comprises one
or more exogenous polynucleotide(s) and an increased level of one
or more non-polar lipid(s) relative to a corresponding non-human
organism or a part thereof, respectively, lacking the one or more
exogenous polynucleotide(s), wherein each of the one or more
exogenous polynucleotides is operably linked to a promoter which is
capable of directing expression of the polynucleotide in a
non-human organism or part thereof,
[0305] (b) the non-human organism is an alga selected from the
group consisting of diatoms (bacillariophytes), green algae
(chlorophytes), blue-green algae (cyanophytes), golden-brown algae
(chrysophytes), haptophytes, brown algae and heterokont algae,
[0306] (c) the one or more non-polar lipid(s) comprise a fatty acid
which comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof; or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains,
[0307] (d) the total fatty acid content in the non-polar lipid(s)
comprises at least 2% more oleic acid and/or at least 2% less
palmitic acid than the non-polar lipid(s) in the corresponding
non-human organism or part thereof lacking the one or more
exogenous polynucleotides of part (a),
[0308] (e) the non-polar lipid(s) comprise a modified level of
total sterols, preferably free (non-esterified) sterols, steroyl
esters, steroyl glycosides, relative to the non-polar lipid(s) in
the corresponding non-human organism or part thereof lacking the
one or more exogenous polynucleotides of part (a),
[0309] (f) the non-polar lipid(s) comprise waxes and/or wax
esters,
[0310] (g) the non-human organism or part thereof is one member of
a pooled population or collection of at least about 1000 such
non-human organisms or parts thereof, respectively, from which the
lipid is extracted.
[0311] In an embodiment of the third aspect, the invention provides
a plant comprising a vegetative part, or the vegetative part
thereof, wherein the vegetative part has a total non-polar lipid
content of at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, or more preferably at least about 15% (w/w dry weight).
In a further preferred embodiment, the total non-polar lipid
content is between 5% and 25%, between 7% and 25%, between 10% and
25%, between 12% and 25%, between 15% and 25%, between 7% and 20%,
between 10% and 20%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
or about 22%, each as a percentage of dry weight. In a particularly
preferred embodiment, the vegetative plant part is a leaf (or
leaves) or a portion thereof. In a more preferred embodiment, the
vegetative plant part is a leaf portion having a surface area of at
least 1 cm.sup.2. In a further embodiment, the non-polar lipid
comprises at least 90% triacylglycerols (TAG). Preferably the plant
is fertile, morphologically normal, and/or agronomically useful.
Seed of the plant preferably germinates at a rate substantially the
same as for a corresponding wild-type plant. Preferably the
vegetative part is a leaf or a stem, or a combination of the two,
or a root or tuber such as, for example, potato tubers.
[0312] In another embodiment, the non-human organism, preferably
plant, or part thereof such as vegetative plant part or seed
comprises one or more exogenous polynucleotides as defined herein
and has an increased level of the one or more non-polar lipids
and/or the total non-polar lipid content which is at least 2-fold,
at least 3-fold, at least 4-fold, at least 5-fold, at least 6-fold,
at least 7-fold, at least 8-fold, at least 9-fold, at least
10-fold, or at least 12-fold, preferably at least about 13-fold or
at least about 15-fold greater on a relative basis than a
corresponding non-human organism, preferably plant, or part thereof
such as vegetative plant part or seed lacking the one or more
exogenous polynucleotides.
[0313] In an embodiment, the invention provides a canola plant
comprising canola seed whose oil content is at least 45% on a
weight basis. Preferably, the canola plant or its seed have
features as described in the first and second aspects of the
invention.
[0314] In an embodiment, the invention provides a corn plant
comprising corn seed whose oil content is at least 5% on a weight
basis. Preferably, the corn plant or its seed have features as
described in the first and second aspects of the invention.
[0315] In an embodiment, the invention provides a soybean plant
comprising soybean seed whose oil content is at least 20% on a
weight basis. Preferably, the soybean plant or its seed have
features as described in the first and second aspects of the
invention.
[0316] In an embodiment, the invention provides a lupin plant
comprising lupin seed whose oil content is at least 10% on a weight
basis. Preferably, the lupin plant or its seed have features as
described in the first and second aspects of the invention.
[0317] In an embodiment, the invention provides a peanut plant
comprising peanuts whose oil content is at least 50% on a weight
basis. Preferably, the peanut plant or its seed have features as
described in the first and second aspects of the invention.
[0318] In an embodiment, the invention provides a sunflower plant
comprising sunflower seed whose oil content is at least 50% on a
weight basis. Preferably, the sunflower plant or its seed have
features as described in the first and second aspects of the
invention.
[0319] In an embodiment, the invention provides a cotton plant
comprising cotton seed whose oil content is at least 41% on a
weight basis. Preferably, the cotton plant or its seed have
features as described in the first and second aspects of the
invention.
[0320] In an embodiment, the invention provides a safflower plant
comprising safflower seed whose oil content is at least 35% on a
weight basis. Preferably, the safflower plant or its seed have
features as described in the first and second aspects of the
invention.
[0321] In an embodiment, the invention provides a flax plant
comprising flax seed whose oil content is at least 36% on a weight
basis. Preferably, the flax plant or its seed have features as
described in the first and second aspects of the invention.
[0322] In an embodiment, the invention provides a Camelina saliva
plant comprising Camelina saliva seed whose oil content is at least
36% on a weight basis. Preferably, the Camelina saliva plant or its
seed have features as described in the first and second aspects of
the invention.
[0323] In embodiments, the plants may be further defined by
Features (i), (ii) and (iii) as described hereinbefore. In a
preferred embodiment, the plant or the vegetative part comprises
one or more or all of the following features:
[0324] (i) oleic acid in a vegetative part or seed of the plant,
the oleic acid being in an esterified or non-esterified form,
wherein at least 20% (mol %), at least 22% (mol %), at least 30%
(mol %), at least 40% (mol/), at least 50% (mol %), or at least 60%
(mol %), preferably at least 65% (mol %) or at least 66% (mol %) of
the total fatty acids in the lipid content of the vegetative part
or seed is oleic acid,
[0325] (ii) oleic acid in a vegetative part or seed of the plant,
the oleic acid being in an esterified form in non-polar lipid,
wherein at least 20% (mol %), at least 22% (mol %), at least 30%
(mol %), at least 40% (mol %), at least 50%. (mol %), or at least
60% (mol %), preferably at least 65% (mol %) or at least 66% (mol
%) of the total fatty acids in the non-polar lipid content of the
vegetative part or seed is oleic acid,
[0326] (iii) a modified fatty acid in a vegetative part or seed of
the plant, the modified fatty acid being in an esterified or
non-esterified form, preferably in an esterified form in non-polar
lipids of the vegetative part or seed, wherein the modified fatty
acid comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof; or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains, and
[0327] (iv) waxes and/or wax esters in the non-polar lipid of the
vegetative part or seed of the plant.
[0328] In an embodiment, the plant or the vegetative plant part is
a member of a population or collection of at least about 1000 such
plants or parts. That is, each plant or plant part in the
population or collection has essentially the same properties or
comprise the same exogenous nucleic acids as the other members of
the population or collection. Preferably, the plants are homozygous
for the exogenous polynucleotides, which provides a degree of
uniformity. Preferably, the plants are growing in a field. The
collection of vegetative plants parts have preferably been
harvested from plants growing in a field. Preferably, the
vegetative plant parts have been harvested at a time when the yield
of non-polar lipids are at their highest. In one embodiment, the
vegetative plant parts have been harvested about at the time of
flowering. In another embodiment, the vegetative plant parts are
harvested when the plants are at least about 1 month of age. In
another embodiment, the vegetative plant parts are harvested from
about at the time of flowering to about the beginning of
senescence. In another embodiment, the vegetative plant parts are
harvested at least about 1 month after induction of expression of
inducible genes.
[0329] In a further embodiment of the third aspect, the invention
provides a vegetative plant part, non-human organism or a part
thereof, or seed comprising one or more exogenous polynucleotide(s)
and an increased level of one or more non-polar lipid(s) relative
to a corresponding vegetative plant part, non-human organism or a
part thereof, or seed lacking the one or more exogenous
polynucleotide(s), wherein each of the one or more exogenous
polynucleotides is operably linked to a promoter which is capable
of directing expression of the polynucleotide in a vegetative plant
part, non-human organism or part thereof, or seed and wherein one
or more or all of the following features apply:
[0330] (i) the one or more exogenous polynucleotide(s) comprise a
first exogenous polynucleotide which encodes an RNA or
transcription factor polypeptide that increases the expression of
one or more glycolytic or fatty acid biosynthetic genes in a
vegetative plant part, non-human organism or a part thereof; or
seed and a second exogenous polynucleotide which encodes an RNA or
polypeptide involved in biosynthesis of one or more non-polar
lipids,
[0331] (ii) if the non-human organism is a plant, a vegetative part
of the plant has a total non-polar lipid content of at least about
3%, more preferably at least about 5%, preferably at least about
7%, more preferably at least about 10%, more preferably at least
about 11%, more preferably at least about 12%, more preferably at
least about 13%, more preferably at least about 14%, or more
preferably at least about 15% (w/w dry weight),
[0332] (iii) the non-human organism is an alga selected from the
group consisting of diatoms (bacillariophytes), green algae
(chlorophytes), blue-green algae (cyanophytes), golden-brown algae
(chrysophytes), haptophytes, brown algae and heterokont algae,
[0333] (iv) the non-polar lipid(s) comprise a fatty acid which
comprises a hydroxyl group, an epoxy group, a cyclopropane group, a
double carbon-carbon bond, a triple carbon-carbon bond, conjugated
double bonds, a branched chain such as a methylated or hydroxylated
branched chain, or a combination of two or more thereof, or any of
two, three, four, five or six of the aforementioned groups, bonds
or branched chains,
[0334] (v) the vegetative plant part, non-human organism or part
thereof, or seed comprises oleic acid in an esterified or
non-esterified form in its lipid, wherein at least 20% (mol %), at
least 22% (mol %), at least 30% (mol %), at least 40% (mol %), at
least 50% (mol %), or at least 60% (mol %), preferably at least 65%
(mol %) or at least 66% (mol %) of the total fatty acids in the
lipid of the vegetative plant part, non-human organism or part
thereof, or seed is oleic acid,
[0335] (vi) the vegetative plant part, non-human organism or part
thereof, or seed comprises oleic acid in an esterified form in its
non-polar lipid, wherein at least 20% (mol %), at least 22% (mol
%), at least 30% (mol %), at least 40% (mol %), at least 50% (mol
%), or at least 60% (mol %), preferably at least 65% (mol %) or at
least 66% (mol %) of the total fatty acids in the non-polar lipid
of the vegetative plant part, non-human organism or part thereof or
seed is oleic acid,
[0336] (vii) the total fatty acid content in the lipid of the
vegetative plant part, non-human organism or part thereof, or seed
comprises at least 2% more oleic acid and/or at least 2% less
palmitic acid than the lipid in the corresponding vegetative plant
part, non-human organism or part thereof or seed lacking the one or
more exogenous polynucleotides, and/or
[0337] (viii) the total fatty acid content in the non-polar lipid
of the vegetative plant part, non-human organism or part thereof,
or seed comprises at least 2% more oleic acid and/or at least 2%
less palmitic acid than the non-polar lipid in the corresponding
vegetative plant part, non-human organism or part thereof; or seed
lacking the one or more exogenous polynucleotides,
[0338] (ix) the non-polar lipid(s) comprise a modified level of
total sterols, preferably free sterols, steroyl esters and/or
steroyl glycosides,
[0339] (x) the non-polar lipid(s) comprise waxes and/or wax esters,
and
[0340] (xi) the non-human organism or part thereof is one member of
a population or collection of at least about 1000 such non-human
organisms or parts thereof.
[0341] In an embodiment, the one or more exogenous
polynucleotide(s) comprise the first exogenous polynucleotide and
the second exogenous polynucleotide, and wherein one or more or all
of the features (ii) to (xi) apply.
[0342] In an embodiment of (ii) above, the total non-polar lipid
content is between 5% and 25%, between 7% and 25%, between 10% and
25%, between 12% and 25%, between 15% and 25%, between 7% and 20%,
between 10% and 20%, about 10%, about 11%, about 12%, about 13%,
about 14%, about 15%, about 16%, about 17%, about 18%, about 20%,
or about 22%, each as a percentage of dry weight. In a more
preferred embodiment, the vegetative plant part is a leaf portion
having a surface area of at least 1 cm.sup.2.
[0343] In preferred embodiments, the non-human organism or part
thereof is a plant, an alga or an organism suitable for
fermentation such as a fungus. The part of the non-human organism
may be a seed, fruit, or a vegetative part of a plant such as an
aerial plant part or a green part such as a leaf or stem. In
another embodiment, the part is a cell of a multicellular organism.
With respect to the part of the non-human organism, the part
comprises at least one cell of the non-human organism. In further
preferred embodiments, the non-human organism or part thereof is
further defined by features as defined in any of the embodiments
described in the first and second aspects of the invention,
including but not limited to Features (i), (ii) and (iii), and the
exogenous polynucleotides or combinations of exogenous
polynucleotides as defined in any of the embodiments described in
the first and second aspects of the invention.
[0344] In an embodiment, the plant, vegetative plant part,
non-human organism or part thereof, or seed comprises one or more
exogenous polynucleotides which encode:
[0345] i) a Wrinkled 1 (WRI1) transcription factor and a DGAT,
[0346] ii) a WRI1 transcription factor and a DGAT and an
Oleosin,
[0347] iii) a WRI1 transcription factor, a DGAT, a MGAT and an
Oleosin,
[0348] iv) a monoacylglycerol acyltransferase (MGAT),
[0349] v) a diacylglycerol acyltransferase 2 (DGAT2),
[0350] vi) a MGAT and a glycerol-3-phosphate acyltransferase
(GPAT),
[0351] vii) a MGAT and a DGAT,
[0352] viii) a MGAT, a GPAT and a DGAT,
[0353] ix) a WRI1 transcription factor and a MGAT,
[0354] x) a WRI1 transcription factor, a DGAT and a MGAT,
[0355] xi) a WRI1 transcription factor, a DGAT, a MGAT, an Oleosin
and a GPAT,
[0356] xii) a DGAT and an Oleosin, or
[0357] xiii) a MGAT and an Oleosin, and
[0358] xiv) optionally, a silencing suppressor polypeptide,
[0359] wherein each exogenous polynucleotide is operably linked to
a promoter which is capable of directing expression of the
polynucleotide in a plant, vegetative plant part, non-human
organism or part thereof, or seed, respectively. The one or more
exogenous polynucleotides may comprise nucleotides whose sequence
is defined herein. Preferably, the plant, vegetative plant part,
non-human organism or part thereof, or seed is homozygous for the
one or more exogenous polynucleotides. Preferably, the exogenous
polynucleotides are integrated into the genome of the plant,
vegetative plant part, non-human organism or part thereof, or seed.
The one or more polynucleotides may be provided as separate
molecules or may be provided as a contiguous single molecule.
Preferably, the exogenous polynucleotides are integrated in the
genome of the plant or organism at a single genetic locus or
genetically linked loci, more preferably in the homozygous state.
More preferably, the integrated exogenous polynucleotides are
genetically linked with a selectable marker gene such as an
herbicide tolerance gene.
[0360] In a preferred embodiment, the vegetative plant part, the
non-human organism or part thereof or the seed comprises a first
exogenous polynucleotide encoding a WRI1 and a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1.
[0361] In another preferred embodiment, the vegetative plant part,
the non-human organism or part thereof, or the seed comprises a
first exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, and a third
exogenous polynucleotide encoding an oleosin.
[0362] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding an MGAT, preferably an MGAT2.
[0363] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding LEC2 or BBM.
[0364] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an MGAT, preferably an MGAT2, and a fifth
exogenous polynucleotide encoding LEC2 or BBM.
[0365] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, and a fourth
exogenous polynucleotide encoding an RNA molecule which inhibits
expression of a gene encoding a lipase such as a CGi58
polypeptide.
[0366] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, and a
fifth exogenous polynucleotide encoding LEC2 or BBM.
[0367] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, and a
fifth exogenous polynucleotide encoding an MGAT, preferably an
MGAT2.
[0368] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed comprises a first
exogenous polynucleotide encoding a WRI1, a second exogenous
polynucleotide encoding a DGAT, preferably a DGAT1, a third
exogenous polynucleotide encoding an oleosin, a fourth exogenous
polynucleotide encoding an RNA molecule which inhibits expression
of a gene encoding a lipase such as a CGi58 polypeptide, a fifth
exogenous polynucleotide encoding an MGAT, preferably an MGAT2, and
a sixth exogenous polynucleotide encoding LEC2 or BBM.
[0369] In an embodiment, the seed comprises a first exogenous
polynucleotide encoding a WRI1, a second exogenous polynucleotide
encoding a DGAT, preferably a DGAT1, a third exogenous
polynucleotide encoding an oleosin, and a fourth exogenous
polynucleotide encoding an MGAT, preferably an MGAT2. Preferably,
the seed further comprises a fifth exogenous polynucleotide
encoding a GPAT.
[0370] Where relevant, instead of a polynucleotide encoding an RNA
molecule which inhibits expression of a gene encoding a lipase such
as a CGi58 polypeptide, the vegetative plant part, the non-human
organism or part thereof, or the seed has one or more introduced
mutations in the lipase gene such as a CGi58 gene which confers
reduced levels of the lipase polypeptide when compared to an
isogenic vegetative plant part, non-human organism or part thereof,
or seed lacking the mutation.
[0371] In a preferred embodiment, the exogenous polynucleotides
encoding the DGAT and oleosin are operably linked to a constitutive
promoter, or a promoter active in green tissues of a plant at least
before and up until flowering, which is capable of directing
expression of the polynucleotides in the vegetative plant part, the
non-human organism or part thereof, or the seed. In a further
preferred embodiment, the exogenous polynucleotide encoding WRI1,
and RNA molecule which inhibits expression of a gene encoding a
lipase such as a CGi58 polypeptide, is operably linked to a
constitutive promoter, a promoter active in green tissues of a
plant at least before and up until flowering, or an inducible
promoter, which is capable of directing expression of the
polynucleotides in the vegetative plant part, the non-human
organism or part thereof, or the seed. In yet a further preferred
embodiment, the exogenous polynucleotides encoding LEC2, BBM and/or
MGAT2 are operably linked to an inducible promoter which is capable
of directing expression of the polynucleotides in the vegetative
plant part, the non-human organism or part thereof, or the
seed.
[0372] In each of the above embodiments, the total non-polar lipid
content of the vegetative plant part, or non-human organism or part
thereof; or the seed, preferably a plant leaf or part thereof stem
or tuber, is at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, or more preferably at least about 15% (w/w dry weight or
seed weight). In a further preferred embodiment, the total
non-polar lipid content is between 5% and 25%, between 7% and 25%,
between 10% and 25%, between 12% and 25%, between 15% and 25%,
between 7% and 20%, between 10% and 20%, between 10% and 15%,
between 15% and 20%, between 20% and 25%, about 10%, about 11%,
about 12%, about 13%, about 14%, about 15%, about 16%, about 17%,
about 18%, about 20%, or about 22%, each as a percentage of dry
weight or seed weight. In a particularly preferred embodiment, the
vegetative plant part is a leaf (or leaves) or a portion thereof.
In a more preferred embodiment, the vegetative plant part is a leaf
portion having a surface area of at least 1 cm.sup.2.
[0373] Furthermore, in each of the above embodiments, the total TAG
content of the vegetative plant part, or non-human organism or part
thereof; or the seed, preferably a plant leaf or part thereof, stem
or tuber, is at least about 3%, more preferably at least about 5%,
preferably at least about 7%, more preferably at least about 10%,
more preferably at least about 11%, more preferably at least about
12%, more preferably at least about 13%, more preferably at least
about 14%, more preferably at least about 15%, or more preferably
at least about 17% (w/w dry weight or seed weight). In a further
preferred embodiment, the total TAG content is between 5% and 30%,
between 7% and 30%, between 10% and 30%, between 12% and 30%,
between 15% and 30%, between 7% and 30%, between 10% and 30%,
between 20% and 28%, between 18% and 25%, between 22% and 30%,
about 10%, about 11%, about 12%, about 13%, about 14%, about 15%,
about 16%, about 17%, about 18%, about 20%, or about 22%, each as a
percentage of dry weight or seed weight. In a particularly
preferred embodiment, the vegetative plant part is a leaf (or
leaves) or a portion thereof. In a more preferred embodiment, the
vegetative plant part is a leaf portion having a surface area of at
least 1 cm.sup.2.
[0374] Furthermore, in each of the above embodiments, the total
lipid content of the vegetative plant part, or non-human organism
or part thereof, or the seed, preferably a plant leaf or part
thereof, stem or tuber, is at least about 3%, more preferably at
least about 5%, preferably at least about 7%, more preferably at
least about 10%, more preferably at least about 11%, more
preferably at least about 12%, more preferably at least about 13%,
more preferably at least about 14%, more preferably at least about
15%, more preferably at least about 17% (w/w dry weight or seed
weight), more preferably at least about 20%, more preferably at
least about 25%. In a further preferred embodiment, the total lipid
content is between 5% and 35%, between 7% and 35%, between
10.degree. % and 35%, between 12% and 35%, between 15% and 35%,
between 7% and 35%, between 10% and 20%, between 18% and 28%,
between 20.degree. 0h and 28%, between 22% and 28%, about
10.degree. 0%, about 11%, about 12%, about 13%, about 14%, about
15%, about 16%, about 17%, about 18%, about 20%, about 22%, or
about 25%, each as a percentage of dry weight or seed weight.
Typically, the total lipid content of the vegetative plant part, or
non-human organism or part thereof is about 2-3% higher than the
non-polar lipid content. In a particularly preferred embodiment,
the vegetative plant part is a leaf (or leaves) or a portion
thereof. In a more preferred embodiment, the vegetative plant part
is a leaf portion having a surface area of at least 1 cm.sup.2.
[0375] In an embodiment, the vegetative plant part, the non-human
organism or part thereof, or the seed, preferably the vegetative
plant part, comprises a first exogenous polynucleotide encoding a
WRI1, a second exogenous polynucleotide encoding a DGAT, preferably
a DGAT1, a third exogenous polynucleotide encoding an MGAT,
preferably an MGAT2, and a fourth exogenous polynucleotide encoding
an oleosin, wherein the vegetative plant part, non-human organism
or part thereof, or seed has one or more or all of the following
features:
[0376] i) a total lipid content of at least 8%, at least 10%, at
least 12%, at least 14%, or at least 15.5% (% weight of dry weight
or seed weight),
[0377] ii) at least a 3 fold, at least a 5 fold, at least a 7 fold,
at least an 8 fold, or least a fold, at higher total lipid content
in the vegetative plant part or non-human organism relative to a
corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0378] iii) a total TAG content of at least 5%, at least 6%, at
least 6.5% or at least 7% (% weight of dry weight or seed
weight),
[0379] iv) at least a 40 fold, at least a 50 fold, at least a 60
fold, or at least a 70 fold, or at least a 100 fold, higher total
TAG content relative to a corresponding vegetative plant part or
non-human organism lacking the exogenous polynucleotides,
[0380] v) oleic acid comprises at least 15%, at least 19% or at
least 22% (% weight) of the fatty acids in TAG,
[0381] vi) at least a 10 fold, at least a 15 fold or at least a 17
fold higher level of oleic acid in TAG relative to a corresponding
vegetative plant part or non-human organism lacking the exogenous
polynucleotides,
[0382] vii) palmitic acid comprises at least 20%, at least 25%, at
least 30% or at least 33% (% weight) of the fatty acids in TAG,
[0383] viii) at least a 1.5 fold higher level of palmitic acid in
TAG relative to a corresponding vegetative plant part on non-human
organism lacking the exogenous polynucleotides,
[0384] ix) linoleic acid comprises at least 22%, at least 25%, at
least 30% or at least 34% (% weight) of the fatty acids in TAG,
[0385] x) .alpha.-linolenic acid comprises less than 20%, less than
15%, less than 11% or less than 8% (% weight) of the fatty acids in
TAG, and
[0386] xi) at least a 5 fold, or at least an 8 fold, lower level of
.alpha.-linolenic acid in TAG relative to a corresponding
vegetative plant part or non-human organism lacking the exogenous
polynucleotides. In this embodiment, preferably the vegetative
plant part at least has feature(s), i), ii) iii), iv), i) and ii),
i) and iii), i) and iv), i) to iii), i), iii) and iv), i) to iv),
ii) and iii), ii) and iv), ii) to iv), or iii) and iv). In an
embodiment, % dry weight is % leaf dry weight.
[0387] In a further embodiment, the vegetative plant part, the
non-human organism or part thereof, or the seed, preferably the
vegetative plant part, comprises a first exogenous polynucleotide
encoding a WRI1, a second exogenous polynucleotide encoding a DGAT,
preferably a DGAT1, a third exogenous polynucleotide encoding an
oleosin, wherein the vegetative plant part, non-human organism or
part thereof, or seed has one or more or all of the following
features:
[0388] i) a total TAG content of at least 10%, at least 12.5%, at
least 15% or at least 17% (% weight of dry weight or seed
weight),
[0389] ii) least a 40 fold, at least a 50 fold, at least a 60 fold,
or at least a 70 fold, or at least a 100 fold, higher total TAG
content in the vegetative plant part or non-human organism relative
to a corresponding vegetative plant part or non-human organism
lacking the exogenous polynucleotides,
[0390] iii) oleic acid comprises at least 19%, at least 22%, or at
least 25% (% weight) of the fatty acids in TAG,
[0391] iv) at least a 10 fold, at least a 15 fold, at least a 17
fold, or at least a 19 fold, higher level of oleic acid in TAG in
the vegetative plant part or non-human organism relative to a
corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0392] v) palmitic acid comprises at least 20%, at least 25%, or at
least 28% (% weight) of the fatty acids in TAG,
[0393] vi) at least a 1.25 fold higher level of palmitic acid in
TAG in the vegetative plant part or non-human organism relative to
a corresponding vegetative plant part or non-human organism lacking
the exogenous polynucleotides,
[0394] vii) linoleic acid comprises at least 15%, or at least 20%,
(% weight) of the fatty acids in TAG,
[0395] viii) .alpha.-linolenic acid comprises less than 15%, less
than 11% or less than 8% (% weight) of the fatty acids in TAG,
and
[0396] ix) at least a 5 fold, or at least an 8 fold, lower level of
.alpha.-linolenic acid in TAG in the vegetative plant part or
non-human organism relative to a corresponding vegetative plant
part or non-human organism lacking the exogenous polynucleotides.
In this embodiment, preferably the vegetative plant part at least
has feature(s), i), ii), or i) and ii). In an embodiment, % dry
weight is % leaf dry weight.
[0397] Preferably, the defined features for the two above
embodiments are as at the flowering stage of the plant.
[0398] In a fourth aspect, the invention provides a plant seed
capable of growing into a plant of the invention, or obtained from
a plant of the invention, for example a non-human organism of the
invention which is a plant. In an embodiment, the seed comprises
one or more exogenous polynucleotides as defined herein.
[0399] In a fifth aspect, the invention provides a process for
obtaining a cell with enhanced ability to produce one or more
non-polar lipids, the process comprising the steps of: [0400] a)
introducing into a cell one or more exogenous polynucleotides,
[0401] b) expressing the one or more exogenous polynucleotides in
the cell or a progeny cell thereof, [0402] c) analysing the lipid
content of the cell or progeny cell, and [0403] d) selecting a cell
or progeny cell having an increased level of one or more non-polar
lipids relative to a corresponding cell or progeny cell lacking the
exogenous polynucleotides, wherein the one or more exogenous
polynucleotides encode
[0404] i) a Wrinkled 1 (WRI1) transcription factor and a DGAT,
[0405] ii) a WRI1 transcription factor and a DGAT and an
Oleosin,
[0406] iii) a WRI1 transcription factor, a DGAT, a MGAT and an
Oleosin,
[0407] iv) a monoacylglycerol acyltransferase (MGAT),
[0408] v) a diacylglycerol acyltransferase 2 (DGAT2),
[0409] vi) a MGAT and a glycerol-3-phosphate acyltransferase
(GPAT),
[0410] vii) a MGAT and a DGAT,
[0411] viii) a MGAT, a GPAT and a DGAT,
[0412] ix) a WRI1 transcription factor and a MGAT,
[0413] x) a WRI1 transcription factor, a DGAT and a MGAT,
[0414] xi) a WRI1 transcription factor, a DGAT, a MGAT, an Oleosin
and a GPAT,
[0415] xii) a DGAT and an Oleosin, or
[0416] xiii) a MGAT and an Oleosin, and
[0417] xiv) optionally, a silencing suppressor polypeptide,
[0418] wherein each exogenous polynucleotide is operably linked to
a promoter that is capable of directing expression of the exogenous
polynucleotide in the cell or progeny cell.
[0419] In an embodiment, the selected cell or progeny cell
comprises:
[0420] i) a first exogenous polynucleotide encoding a WRI1 and a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1,
[0421] ii) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, and a third exogenous polynucleotide encoding an
oleosin,
[0422] iii) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, and a
fourth exogenous polynucleotide encoding an MGAT, preferably an
MGAT2,
[0423] iv) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, and a
fourth exogenous polynucleotide encoding LEC2 or BBM,
[0424] v) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, a
fourth exogenous polynucleotide encoding an MGAT, preferably an
MGAT2, and a fifth exogenous polynucleotide encoding LEC2 or
BBM,
[0425] vi) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, and a
fourth exogenous polynucleotide encoding an RNA molecule which
inhibits expression of a gene encoding a lipase such as a CGi58
polypeptide,
[0426] vii) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, a
fourth exogenous polynucleotide encoding an RNA molecule which
inhibits expression of a gene encoding a lipase such as a CGi58
polypeptide, and a fifth exogenous polynucleotide encoding LEC2 or
BBM,
[0427] viii) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, a
fourth exogenous polynucleotide encoding an RNA molecule which
inhibits expression of a gene encoding a lipase such as a CGi58
polypeptide, and a fifth exogenous polynucleotide encoding an MGAT,
preferably an MGAT2, or
[0428] ix) a first exogenous polynucleotide encoding a WRI1, a
second exogenous polynucleotide encoding a DGAT, preferably a
DGAT1, a third exogenous polynucleotide encoding an oleosin, a
fourth exogenous polynucleotide encoding an RNA molecule which
inhibits expression of a gene encoding a lipase such as a CGi58
polypeptide, a fifth exogenous polynucleotide encoding an MGAT,
preferably an MGAT2, and a sixth exogenous polynucleotide encoding
LEC2 or BBM.
[0429] In a further embodiment, the selected cell or progeny cell
is a cell of a plant seed and comprises a first exogenous
polynucleotide encoding a WRI1, a second exogenous polynucleotide
encoding a DGAT, preferably a DGAT1, a third exogenous
polynucleotide encoding an oleosin, and a fourth exogenous
polynucleotide encoding an MGAT, preferably an MGAT2. Preferably,
the seed further comprises a fifth exogenous polynucleotide
encoding a GPAT.
[0430] In a preferred embodiment, the one or more exogenous
polynucleotides are stably integrated into the genome of the cell
or progeny cell.
[0431] In a preferred embodiment, the process further comprises a
step of regenerating a transgenic plant from the cell or progeny
cell comprising the one or more exogenous polynucleotides. The step
of regenerating a transgenic plant may be performed prior to the
step of expressing the one or more exogenous polynucleotides in the
cell or a progeny cell thereof, and/or prior to the step of
analysing the lipid content of the cell or progeny cell, and/or
prior to the step of selecting the cell or progeny cell having an
increased level of one or more non-polar lipids. The process may
further comprise a step of obtaining seed or a progeny plant from
the transgenic plant, wherein the seed or progeny plant comprises
the one or more exogenous polynucleotides.
[0432] The process of the fifth aspect may be used as a screening
assay to determine whether a polypeptide encoded by an exogenous
polynucleotide has a desired function. The one or more exogenous
polynucleotides in this aspect may comprise a sequence as defined
above. Further, the one or more exogenous polynucleotides may not
be known prior to the process to encode a WRI1 transcription factor
and a DGAT, a WRI1 transcription factor and a MGAT, a WRI1
transcription factor, a DGAT and a MGAT, a WRI1 transcription
factor, a DGAT, a MGAT and an Oleosin, a WRI1 transcription factor,
a DGAT, a MGAT, an Oleosin and a GPAT, a WRI1 transcription factor,
a DGAT and an oleosin, a DGAT and an Oleosin, or a MGAT and an
Oleosin, but rather may be candidates therefor. The process
therefore may be used as an assay to identify or select
polynucleotides encoding a WRI1 transcription factor and a DGAT, a
WRI1 transcription factor and a MGAT, a WRI1 transcription factor,
a DGAT and a MGAT, a WRI1 transcription factor, a DGAT, a MGAT and
an Oleosin, a WRI1 transcription factor, a DGAT, a MGAT, an Oleosin
and a GPAT, a WRI1 transcription factor, a DGAT and an oleosin, a
DGAT and an Oleosin, or a MGAT and an Oleosin. The candidate
polynucleotides are introduced into a cell and the products
analysed to determine whether the candidates have the desired
function.
[0433] In a sixth aspect, the invention provides a transgenic cell
or transgenic plant obtained using a process of the invention, or a
vegetative plant part or seed obtained therefrom which comprises
the one or more exogenous polynucleotides.
[0434] In a seventh aspect, the invention provides a use of one or
more polynucleotides encoding, or a genetic construct comprising
polynucleotides encoding:
[0435] i) a Wrinkled 1 (WRI1) transcription factor and a DGAT,
[0436] ii) a WRI1 transcription factor and a DGAT and an
Oleosin,
[0437] iii) a WRI1 transcription factor, a DGAT, a MGAT and an
Oleosin,
[0438] iv) a monoacylglycerol acyltransferase (MGAT),
[0439] v) a diacylglycerol acyltransferase 2 (DGAT2),
[0440] vi) a MGAT and a glycerol-3-phosphate acyltransferase
(GPAT),
[0441] vii) a MGAT and a DGAT,
[0442] viii) a MGAT, a GPAT and a DGAT,
[0443] ix) a WRI1 transcription factor and a MGAT,
[0444] x) a WRI1 transcription factor, a DGAT and a MGAT,
[0445] xi) a WRI1 transcription factor, a DGAT, a MGAT, an Oleosin
and a GPAT,
[0446] xii) a DGAT and an Oleosin, or
[0447] xiii) a MGAT and an Oleosin, and
[0448] xiv) optionally, a silencing suppressor polypeptide,
for producing a transgenic cell, a transgenic non-human organism or
a part thereof or a transgenic seed having an enhanced ability to
produce one or more non-polar lipids relative to a corresponding
cell, non-human organism or part thereof, or seed lacking the one
or more polynucleotides, wherein each of the one or more
polynucleotides is exogenous to the cell, non-human organism or
part thereof, or seed and is operably linked to a promoter which is
capable of directing expression of the polynucleotide in a cell, a
non-human organism or a part thereof or a seed, respectively.
[0449] In an embodiment, the invention provides a use of a first
polynucleotide encoding an RNA or transcription factor polypeptide
that increases the expression of one or more glycolytic or fatty
acid biosynthetic genes in a cell, a non-human organism or a part
thereof, or a seed, together with a second polynucleotide that
encodes an RNA or polypeptide involved in biosynthesis of one or
more non-polar lipids, for producing a transgenic cell, a
transgenic non-human organism or part thereof, or a transgenic seed
having an enhanced ability to produce one or more non-polar lipids
relative to a corresponding cell, non-human organism or part
thereof, or seed lacking the first and second polynucleotides,
wherein the first and second polynucleotides are each exogenous to
the cell, non-human organism or part thereof, or seed and are each
operably linked to a promoter which is capable of directing
expression of the polynucleotide in the transgenic cell, transgenic
non-human organism or part thereof; or transgenic seed,
respectively.
[0450] In a further embodiment, the invention provides a use of one
or more polynucleotides for producing a transgenic cell, a
transgenic non-human organism or part thereof, or a transgenic seed
having an enhanced ability to produce one or more non-polar
lipid(s) relative to a corresponding cell, non-human organism or
part thereof, or seed lacking the one or more exogenous
polynucleotides, wherein each of the one or more polynucleotides is
exogenous to the cell, non-human organism or part thereof, or seed
and is operably linked to a promoter which is capable of directing
expression of the polynucleotide in a cell, a non-human organism or
a part thereof, or a seed, respectively, and wherein the non-polar
lipid(s) comprise a fatty acid which comprises a hydroxyl group, an
epoxy group, a cyclopropane group, a double carbon-carbon bond, a
triple carbon-carbon bond, conjugated double bonds, a branched
chain such as a methylated or hydroxylated branched chain, or a
combination of two or more thereof; or any of two, three, four,
five or six of the aforementioned groups, bonds or branched chains.
Such uses also have utility as screening assays.
[0451] In an eighth aspect, the invention provides a process for
producing seed, the process comprising:
[0452] i) growing a plant, multiple plants, or non-human organism
according to the invention, and
[0453] ii) harvesting seed from the plant, plants, or non-human
organism.
In a preferred embodiment, the process comprises growing a
population of at least about 1000 such plants in a field, and
harvesting seed from the population of plants. The harvested seed
may be placed in a container and transported away from the field,
for example exported out of the country, or stored prior to
use.
[0454] In a ninth aspect, the invention provides a fermentation
process comprising the steps of:
[0455] i) providing a vessel containing a liquid composition
comprising a non-human organism of the invention which is suitable
for fermentation, and constituents required for fermentation and
fatty acid biosynthesis, and
[0456] ii) providing conditions conducive to the fermentation of
the liquid composition contained in said vessel.
[0457] In a tenth aspect, the invention provides a recovered or
extracted lipid obtainable by a process of the invention, or
obtainable from a vegetative plant part, non-human organism or part
thereof, cell or progeny cell, transgenic plant, or seed of the
invention. The recovered or extracted lipid, preferably oil such as
seedoil, may have an enhanced TAG content, DAG content, TAG and DAG
content, MAG content, PUFA content, specific PUFA content, or a
specific fatty acid content, and/or total non-polar lipid content.
In a preferred embodiment, the MAG is 2-MAG. The extent of the
increased TAG content, DAG content, TAG and DAG content, MAG
content, PUFA content, specific PUFA content, specific fatty acid
content and/or total non-polar lipid content may be as defined in
Feature (i).
[0458] In an eleventh aspect, the invention provides an industrial
product produced by a process of the invention, preferably which is
a hydrocarbon product such as fatty acid esters, preferably fatty
acid methyl esters and/or a fatty acid ethyl esters, an alkane such
as methane, ethane or a longer-chain alkane, a mixture of longer
chain alkanes, an alkene, a biofuel, carbon monoxide and/or
hydrogen gas, a bioalcohol such as ethanol, propanol, or butanol,
biochar, or a combination of carbon monoxide, hydrogen and
biochar.
[0459] In a twelfth aspect, the invention provides a use of a
plant, vegetative plant part, non-human organism or a part thereof,
cell or progeny cell, transgenic plant produced by a process of the
invention, or a seed or a recovered or extracted lipid of the
invention for the manufacture of an industrial product. The
industrial product may be as defined above.
[0460] In a thirteenth aspect, the invention provides a process for
producing fuel, the process comprising:
[0461] i) reacting a lipid of the invention with an alcohol,
optionally in the presence of a catalyst, to produce alkyl esters,
and
[0462] ii) optionally, blending the alkyl esters with petroleum
based fuel. The alkyl esters are preferably methyl esters. The fuel
produced by the process may comprise a minimum level of the lipid
of the invention or a hydrocarbon product produced therefrom such
as at least 10%, at least 20%, or at least 30% by volume.
[0463] In a fourteenth aspect, the invention provides a process for
producing a synthetic diesel fuel, the process comprising:
[0464] i) converting lipid in a vegetative plant, non-human
organism or part thereof of the invention to a syngas by
gasification, and
[0465] ii) converting the syngas to a biofuel using a metal
catalyst or a microbial catalyst.
[0466] In a fifteenth aspect, the invention provides a process for
producing a biofuel, the process comprising converting lipid in a
vegetative plant part, non-human organism or part thereof of the
invention to bio-oil by pyrolysis, a bioalcohol by fermentation, or
a biogas by gasification or anaerobic digestion.
[0467] In a sixteenth aspect, the invention provides a process for
producing a feedstuff, the process comprising admixing a plant,
vegetative plant part thereof, non-human organism or part thereof;
cell or progeny cell, transgenic plant produced by a process of the
invention, seed, recovered or extracted lipid, or an extract or
portion thereof, with at least one other food ingredient.
[0468] In a seventeenth aspect, the invention provides feedstuffs,
cosmetics or chemicals comprising a plant, vegetative part thereof,
non-human organism or part thereof, cell or progeny cell,
transgenic plant produced by a process of the invention, seed, or a
recovered or extracted lipid of the invention, or an extract or
portion thereof.
[0469] Naturally, when vegetative material of a plant is to be
harvested because of its oil content it is desirable to harvest the
material when lipid levels are as high as possible. The present
inventors have noted an association between the glossiness of the
vegetative tissue of the plants of the invention and oil content,
with high levels of lipid being associated with high gloss. Thus,
the glossiness of the vegetative material can be used as marker to
assist in determining when to harvest the material.
[0470] In a further aspect, the invention provides a recombinant
cell comprising one or more exogenous polynucleotide(s) and an
increased level of one or more non-polar lipid(s) relative to a
corresponding cell lacking the one or more exogenous
polynucleotide(s),
[0471] wherein each of the one or more exogenous polynucleotides is
operably linked to a promoter which is capable of directing
expression of the polynucleotide in a cell, and wherein one or more
or all of the following features apply:
[0472] (a) the one or more exogenous polynucleotide(s) comprise a
first exogenous polynucleotide which encodes an RNA or
transcription factor polypeptide that increases the expression of
one or more glycolytic or fatty acid biosynthetic genes in a
non-human organism or a part thereof, and a second exogenous
polynucleotide which encodes an RNA or polypeptide involved in
biosynthesis of one or more non-polar lipids,
[0473] (b) if the cell is a cell of a vegetative part of a plant,
the cell has a total non-polar lipid content of at least about 3%,
more preferably at least about 5%, preferably at least about 7%,
more preferably at least about 10%, more preferably at least about
11%, more preferably at least about 12%, more preferably at least
about 13%, more preferably at least about 14%, or more preferably
at least about 15% (w/w),
[0474] (c) the cell is an alga selected from the group consisting
of diatoms (bacillariophytes), green algae (chlorophytes),
blue-green algae (cyanophytes), golden-brown algae (chrysophytes),
haptophytes, brown algae and heterokont algae,
[0475] (d) the one or more non-polar lipid(s) comprise a fatty acid
which comprises a hydroxyl group, an epoxy group, a cyclopropane
group, a double carbon-carbon bond, a triple carbon-carbon bond,
conjugated double bonds, a branched chain such as a methylated or
hydroxylated branched chain, or a combination of two or more
thereof, or any of two, three, four, five or six of the
aforementioned groups, bonds or branched chains,
[0476] (e) the total fatty acid content in the non-polar lipid(s)
comprises at least 2% more oleic acid and/or at least 2% less
palmitic acid than the non-polar lipid(s) in the corresponding cell
lacking the one or more exogenous polynucleotides,
[0477] (f) the non-polar lipid(s) comprise a modified level of
total sterols, preferably free (non-esterified) sterols, steroyl
esters, steroyl glycosides, relative to the non-polar lipid(s) in
the corresponding cell lacking the one or more exogenous
polynucleotides,
[0478] (g) the non-polar lipid(s) comprise waxes and/or wax esters,
and
[0479] (h) the cell is one member of a population or collection of
at least about 1000 such cells.
[0480] In an embodiment, the one or more exogenous
polynucleotide(s) comprise the first exogenous polynucleotide and
the second exogenous polynucleotide, and wherein one or more or all
of the features (b) to (h) apply.
[0481] In a further aspect, the present invention provides a method
of determining when to harvest a plant to optimize the amount of
lipid in the vegetative tissue of the plant at harvest, the method
comprising
[0482] i) measuring the gloss of the vegetative tissue,
[0483] ii) comparing the measurement with a pre-determined minimum
glossiness level, and
[0484] iii) optionally harvesting the plant.
[0485] In another aspect, the present invention provides a method
of predicting the quantity of lipid in vegetative tissue of a
plant, the method comprising measuring the gloss of the vegetative
tissue.
[0486] In a preferred embodiment of the two above aspects the
vegetative tissue is a leaf (leaves) or a portion thereof.
[0487] In a further aspect, the present invention provides a method
of trading a plant or a part thereof; comprising obtaining the
plant or part comprising a cell of the invention, and trading the
obtained plant or plant part for pecuniary gain.
[0488] In an embodiment, the method further comprises one or more
or all of:
[0489] i) cultivating the plant,
[0490] ii) harvesting the plant part from the plant,
[0491] iii) storing the plant or part thereof, or
[0492] iv) transporting the plant or part thereof to a different
location.
[0493] In a further aspect, the present invention provides a
process for producing bins of plant parts comprising:
[0494] a) harvesting plant parts comprising a cell of the invention
by collecting the plant parts from the plants, or by separating the
plant parts from other parts of the plants,
[0495] b) optionally, sifting and/or sorting the harvested plant
parts, and
[0496] c) loading the plant parts of a) or the sifted and/or sorted
plant parts of b) into bins, thereby producing bins of the plant
parts.
[0497] Any embodiment herein shall be taken to apply mutatis
mutandis to any other embodiment unless specifically stated
otherwise.
[0498] The present invention is not to be limited in scope by the
specific embodiments described herein, which are intended for the
purpose of exemplification only. Functionally-equivalent products,
compositions and methods are clearly within the scope of the
invention, as described herein.
[0499] Throughout this specification, unless specifically stated
otherwise or the context requires otherwise, reference to a single
step, composition of matter, group of steps or group of
compositions of matter shall be taken to encompass one and a
plurality (i.e. one or more) of those steps, compositions of
matter, groups of steps or group of compositions of matter.
[0500] The invention is hereinafter described by way of the
following non-limiting Examples and with reference to the
accompanying figures.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0501] FIG. 1. A representation of various lipid synthesis
pathways, most of which converge at DAG, a central molecule in
lipid synthesis. This model includes one possible route to the
formation of sn-2 MAG which could be used by a bi-functional
MGAT/DGAT for DAG formation from glycerol-3-phosphate (G-3-P).
Abbreviations are as follows:
[0502] G-3-P; glycerol-3-phosphate
[0503] LysoPA; lysophosphatidic acid
[0504] PA; phosphatidic acid
[0505] MAG; monoacylglycerol
[0506] DAG; diacylglycerol
[0507] TAG; triacylglycerol
[0508] Acyl-CoA and FA-CoA; acyl-coenzyme A and fatty acyl-coenzyme
A
[0509] PC; phosphatidylcholine
[0510] GPAT; glycerol-3-phosphate acyltransferase;
glycerol-3-phosphate O-acyltransferase;
acyl-CoA:sn-glycerol-3-phosphate 1-O-acyltransferase; EC
2.3.1.15
[0511] GPAT4; glycerol-3-phosphate acyltransferase 4
[0512] GPAT6; glycerol-3-phosphate acyltransferase 6
[0513] LPAAT; 1-acyl-glycerol-3-phosphate acyltransferase;
1-acylglycerol-3-phosphate O-acyltransferase;
acyl-CoA:1-acyl-sn-glycerol-3-phosphate 2-O-acyltransferase; EC
2.3.1.51
[0514] PAP; phosphatidic acid phosphatase; phosphatidate
phosphatase; phosphatic acid phosphohydrolase; phosphatidic acid
phosphatase; EC 3.1.3.4
[0515] MGAT; an acyltransferase having monoacylglycerol
acyltransferase (MGAT; 2-acylglycerol O-acyltransferase
acyl-CoA:2-acylglycerol O-acyltransferase; EC 2.3.1.22)
activity
[0516] M/DGAT; an acyltransferase having monoacylglycerol
acyltransferase (MGAT; 2-acylglycerol O-acyltransferase;
acyl-CoA:2-acylglycerol O-acyltransferase; EC 2.3.1.22) and/or
diacylglycerol acyltransferase (DGAT; diacylglycerol
O-acyltransferase; acyl-CoA:1,2-diacyl-sn-glycerol
O-acyltransferase; EC 2.3.1.20) activity
[0517] LPCAT; acyl-CoA:lysophosphatidylcholine acyltransferase;
1-acylglycerophosphocholine O-acyltransferase;
acyl-CoA:1-acyl-sn-glycero-3-phosphocholine O-acyltransferase; EC
2.3.1.23
[0518] PLD-Z; Phospholipase D zeta; choline phosphatase;
lecithinase D; lipophosphodiesterase II; EC 3.1.4.4
[0519] CPT; CDP-choline:diacylglycerol cholinephosphotransferase;
1-alkyl-2-acetylglycerol cholinephosphotransferase;
alkylacylglycerol cholinephosphotransferase;
cholinephosphotransferase; phosphoylcholine-glyceride transferase;
EC 2.7.8.2
[0520] PDCT; phosphatidylcholine:diacylglycerol
cholinephosphotransferase
[0521] PLC; phospholipase C; EC 3.1.4.3
[0522] PDAT; phospholipid:diacylglycerol acyltransferase;
phospholipid: 1,2-diacyl-sn-glycerol O-acyltransferase; EC
2.3.1.158
[0523] Pi; inorganic phosphate FIG. 2. Relative DAG and TAG
increases in Nicotiana benthamiana leaf tissue transformed with
constructs encoding p19 (negative control), Arabidopsis thaliana
DGAT1, Mus musculus MGAT1 and a combination of DGAT1 and MGAT1,
each expressed from the 35S promoter. The MGAT1 enzyme was far more
active than the DGAT1 enzyme in promoting both DAG and TAG
accumulation in leaf tissue. Expression of the MGAT1 gene resulted
in twice as much DAG and TAG accunmlation in leaf tissue compared
to expression of DGAT1 alone.
[0524] FIG. 3. Relative TAG increases in N. benthamiana leaf
transformed with constructs encoding p19 (negative control), A.
thaliana DGAT1, M. musculus MGAT2 and a combination of MGAT2 and
DGAT1. Error bars denote standard error of triplicate samples.
[0525] FIG. 4. Radioactivity (DPM) in MAG, DAG and TAG fractions
isolated from transiently-transformed N. benthamiana leaf lysates
fed with sn-2-MAG[.sup.14C] and unlabelled oleic acid over a
time-course. The constructs used were as for FIG. 3.
[0526] FIG. 5. As for FIG. 4 but fed [.sup.14C]G-3-P and unlabelled
oleic acid.
[0527] FIG. 6. Autoradiogram of TLC plate showing TAG-formation by
A. thaliana DGAT1 and M. musculus MGAT1 but not M. musculus MGAT2
in yeast assays. The assay is described in Example 5.
[0528] FIG. 7. TAG levels in Arabidopsis thaliana T2 and T3 seeds
transformed with a chimeric DNA expressing MGAT2 relative to
parental (untransformed) control. Seeds were harvested at maturity
(dessicated). SW: desiccated seed weight. TAG levels are given as
.mu.g TAG per 100 .mu.g seed weight.
[0529] FIG. 8. Total fatty acid content in seed of transformed
Arabidopsis thaliana plants transformed with constructs encoding
MGAT1 or MGAT2.
[0530] FIG. 9. Relative TAG level in transiently-transformed N.
benthamiana leaf tissue compared to Arabidopsis thaliana DGAT1
overexpression.
[0531] FIG. 10. TAG conversion from sn-1,2-DAG in DGAT assay from
microsomes of N. benthamiana leaf tissues expressing P19 control,
Arabidopsis thaliana DGAT1 and Arabidopsis thaliana DGAT2
[0532] FIG. 11. Total FAME quantification in A. thaliana seeds
transformed with pJP3382 and pJP3383.
[0533] FIG. 12. Maximum TAG levels obtained for different gene
combinations transiently expressed in N. benthamiana leaves. The V2
negative control represents the average TAG level based on 15
independent repeats.
[0534] FIG. 13. Co-expression of the genes coding for the
Arabidopsis thaliana DGAT1 acyltransferase and A. thaliana WRI1
transcription factor resulted in a synergistic effect on TAG levels
in Nicotiana benthamiana leaves. Data shown are averages and
standard deviations of five independent infiltrations.
[0535] FIG. 14 TAG levels in stably-transformed N. benthamiana
aerial seedling tissue. Total lipids were extracted from aerial
tissues of N. benthamiana seedlings and analysed by TLC-FID using
an internal DAGE standard to allow accurate comparison between
samples.
[0536] FIG. 15. Total fatty acid levels of A. thaliana T2 seed
populations transformed with control vector (pORE04), M. musculus
MGAT1 (35S:MGAT1) or M. musculus MGAT2 (35S:MGAT2).
[0537] FIG. 16. Map of the insertion region between the left and
right borders of pJP3502. TER Glyma-Lectin denotes the Glycine max
lectin terminator; Arath-WRI1, Arabidopsis thaliana WRI1
transcription factor coding region; PRO Arath-Rubisco SSU, A.
thaliana rubisco small subunit promotor; Sesin-Oleosin, Sesame
indicum oleosin coding region; PRO CaMV35S-Ex2, cauliflower mosaic
virus 35S promoter having a duplicated enhancer region;
Arath-DGAT1, A. thaliana DGAT1 acyltransferase coding region; TER
Agrtu-NOS, Agrobacterium tumefaciens nopaline synthase
terminator.
[0538] FIG. 17. Schematic representation of the construct pJP3503
including the insertion region between the left and right borders
of pJP3503. TER Agrtu-NOS denotes the Agrobacterium tumefaciens
nopaline synthase terminator, Musmu-MGAT2, Mus Musculus MGAT2
acyltransferase; PRO CaMV24S-Ex2, cauliflower mosaic virus 35S
duplicated enhancer region; TER Glyma-Lectin, Glycine max lectin
terminator; Arath-WRI1, Arabidopsis thaliana WRI1 transcription
factor; PRO Arath-Rubisco SSU, A. thaliana rubisco small subunit
promotor; Sesin-Oleosin, Sesame indicum oleosin; Arath-DGAT1, A.
thaliana DGAT1 acyltransferase
[0539] FIG. 18. TAG yields in different aged leaves of three wild
type tobacco plants (wt1-3) and three pJP3503 primary transformants
(4, 29, 21). Leaf stages are indicated by `G`, green; `YG`,
yellow-green; `Y`, yellow. Plant stages during sampling were
budding, wild type 1; first flowers appearing, wild type 2;
flowering, wild type 3; producing seed pods (pJP3503
transformants).
[0540] FIG. 19A. DNA insert containing expression cassettes for the
Umbelopsis ramanniana DGAT2A expressed by the Glycine max alpha'
subunit beta-conglycinin promoter, Arabidopsis thaliana WRI1
expressed by the Glycine max kunitz trypsin inhibitor 3 promoter
and the Mus musculus MGAT2 expressed by the Glycine max alpha'
subunit beta-conglycinin promoter. Gene coding regions and
expression cassettes are excisable by restriction digestion.
[0541] FIG. 19B. DNA insert containing expression cassettes for the
Arabidopsis thaliana LEC2 and WRI1 transcription factor genes
expressed by inducible Aspergillus alcA promoters, the Arabidopsis
thaliana DGAT1 expressed by the constitutive CaMV-35S promoter and
the Aspergillus alcR gene expressed by the constitutive CsVMV
promoter. Expressed of the LEC2 and WRI1 transcription factors is
induced by ethanol or an analagous compound.
[0542] FIG. 20. pJP3507 map
[0543] FIG. 21. pJP3569 map
KEY TO THE SEQUENCE LISTING
[0544] SEQ ID NO:1 Mus musculus codon optimised MGAT1
[0545] SEQ ID NO:2 Mus musculus codon optimised MGAT2
[0546] SEQ ID NO:3 Ciona intestinalis codon optimised MGAT1
[0547] SEQ ID NO:4 Tribolium castaneum codon optimised MGAT1
[0548] SEQ ID NO:5 Danio rerio codon optimised MGAT1
[0549] SEQ ID NO:6 Danio rerio codon optimised MGAT2
[0550] SEQ ID NO:7 Homo sapiens MGAT1 polynucleotide (AF384163)
[0551] SEQ ID NO:8 Mus musculus MGAT1 polynucleotide (AF384162)
[0552] SEQ ID NO:9 Pan troglodytes MGAT1 polynucleotide transcript
variant (XM_001166055)
[0553] SEQ ID NO:10 Pan troglodytes MGAT1 polynucleotide transcript
variant 2 (XM_0526044.2)
[0554] SEQ ID NO:11 Canis familiaris MGAT1 polynucleotide
(XM_545667.2)
[0555] SEQ ID NO:12 Bos taurus MGAT1 polynucleotide
(NM_001001153.2)
[0556] SEQ ID NO:13 Rattus norvegicus MGAT1 polynucleotide
(NM_001108803.1)
[0557] SEQ ID NO:14 Danio rerio MGAT1 polynucleotide
(NM_001122623.1)
[0558] SEQ ID NO:15 Caenorhabditis elegans MGAT1 polynucleotide
(NM_073012.4)
[0559] SEQ ID NO:16 Caenorhabditis elegans MGAT1 polynucleotide
(NM_182380.5)
[0560] SEQ ID NO:17 Caenorhabditis elegans MGAT1 polynucleotide
(NM_065258.3)
[0561] SEQ ID NO:18 Caenorhabditis elegans MGAT1 polynucleotide
(NM_075068.3)
[0562] SEQ ID NO:19 Caenorhabditis elegans MGAT1 polynucleotide
(NM_072248.3)
[0563] SEQ ID NO:20 Kluyveromyces lactis MGAT1 polynucleotide
(XM_455588.1)
[0564] SEQ ID NO:21 Ashbya gossypii MGAT1 polynucleotide
(NM_208895.1)
[0565] SEQ ID NO:22 Magnaporthe oryzae MGAT1 polynucleotide
(XM_368741.1)
[0566] SEQ ID NO:23 Ciona intestinalis MGAT1 polynucleotide
(XM_002120843.1)
[0567] SEQ ID NO:24 Homo sapiens MGAT2 polynucleotide
(AY157608)
[0568] SEQ ID NO:25 Mus musculus MGAT2 polynucleotide
(AY157609)
[0569] SEQ ID NO:26 Pan troglodytes MGAT2 polynucleotide
(XM_522112.2)
[0570] SEQ ID NO:27 Canis familiaris MGAT2 polynucleotide
(XM_542304.1)
[0571] SEQ ID NO:28 Bos taurus MGAT2 polynucleotide
(NM_001099136.1)
[0572] SEQ ID NO:29 Rattus norvegicus MGAT2 polynucleotide
(NM_001109436.2)
[0573] SEQ ID NO:30 Gallus gallus MGAT2 polynucleotide
(XM_424082.2)
[0574] SEQ ID NO:31 Danio rerio MGAT2 polynucleotide
(NM_001006083.1)
[0575] SEQ ID NO:32 Drosophila melanogaster MGAT2 polynucleotide
(NM_136474.2)
[0576] SEQ ID NO:33 Drosophila melanogaster MGAT2 polynucleotide
(NM_136473.2)
[0577] SEQ ID NO:34 Drosophila melanogaster MGAT2 polynucleotide
(NM_136475.2)
[0578] SEQ ID NO:35 Anopheles gambiae MGAT2 polynucleotide
(XM_001688709.1)
[0579] SEQ ID NO:36 Anopheles gambiae MGAT2 polynucleotide
(XM_315985)
[0580] SEQ ID NO:37 Tribolium castaneum MGAT2 polynucleotide
(XM_970053.1)
[0581] SEQ ID NO:38 Homo sapiens MGAT3 polynucleotide
(AY229854)
[0582] SEQ ID NO:39 Pan troglodytes MGAT3 polynucleotide transcript
variant 1 (XM_001154107.1)
[0583] SEQ ID NO:40 Pan troglodytes MGAT3 polynucleotide transcript
variant 2 (XM_001154171.1)
[0584] SEQ ID NO:41 Pan troglodytes MGAT3 polynucleotide transcript
variant 3 (XM_527842.2)
[0585] SEQ ID NO:42 Canis familiaris MGAT3 polynucleotide
(XM_845212.1)
[0586] SEQ ID NO:43 Bos taurus MGAT3 polynucleotide
(XM_870406.4)
[0587] SEQ ID NO:44 Danio rerio MGAT3 polynucleotide
(XM_688413.4)
[0588] SEQ ID NO:45 Homo sapiens MGAT1 polypeptide (AAK84178.1)
[0589] SEQ ID NO:46 Mus musculus MGAT1 polypeptide (AAK84177.1)
[0590] SEQ ID NO:47 Pan troglodytes MGAT1 polypeptide isoform 1
(XP_001166055.1)
[0591] SEQ ID NO:48 Pan troglodytes MGAT1 polypeptide isoform 2
(XP_526044.2)
[0592] SEQ ID NO:49 Canis familiaris MGAT1 polypeptide
(XP_545667.2)
[0593] SEQ ID NO:50 Bos taurus MGAT1 polypeptide
(NP_001001153.1)
[0594] SEQ ID NO:51 Rattus norvegicus MGAT1 polypeptide
(NP_001102273.1)
[0595] SEQ ID NO:52 Danio rerio MGAT1 polypeptide
(NP_001116095.1)
[0596] SEQ ID NO:53 Caenorhabditis elegans MGAT1 polypeptide
(NP_505413.1)
[0597] SEQ ID NO:54 Caenorhabditis elegans MGAT1 polypeptide
(NP_872180.1)
[0598] SEQ ID NO:55 Caenorhabditis elegans MGAT1 polypeptide
(NP_497659.1)
[0599] SEQ ID NO:56 Caenorhabditis elegans MGAT1 polypeptide
(NP_507469.1)
[0600] SEQ ID NO:57 Caenorhabditis elegans MGAT1 polypeptide
(NP_504649.1)
[0601] SEQ ID NO:58 Kluyveromyces lactis MGAT1 polypeptide
(XP_455588.1)
[0602] SEQ ID NO:59 Ashbya gossypii MGAT1 polypeptide
(NP_983542.1)
[0603] SEQ ID NO:60 Magnaporthe oryzae MGAT1 polypeptide
(XP_368741.1)
[0604] SEQ ID NO:61 Ciona intestinalis MGAT1 polypeptide
(XP_002120879)
[0605] SEQ ID NO:62 Homo sapiens MGAT2 polypeptide (AA023672.1)
[0606] SEQ ID NO:63 Mus musculus MGAT2 polypeptide (AA023673.1)
[0607] SEQ ID NO:64 Pan troglodytes MGAT2 polypeptide
(XP_522112.2)
[0608] SEQ ID NO:65 Canis familiaris MGAT2 polypeptide
(XP_542304.1)
[0609] SEQ ID NO:66 Bos taurus MGAT2 polypeptide
(NP_001092606.1)
[0610] SEQ ID NO:67 Rattus norvegicus MGAT2 polypeptide
(NP_001102906.2)
[0611] SEQ ID NO:68 Gallus gallus MGAT2 polypeptide
(XP_424082.2)
[0612] SEQ ID NO:69 Danio rerio MGAT2 polypeptide
(NP_001006083.1)
[0613] SEQ ID NO:70 Drosophila melanogaster MGAT2 polypeptide
(NP_610318.1)
[0614] SEQ ID NO:71 Drosophila melanogaster MGAT2 polypeptide
(NP_610317.1)
[0615] SEQ ID NO:72 Drosophila melanogaster MGAT2 polypeptide
(NP_610319.2)
[0616] SEQ ID NO:73 Anopheles gambiae MGAT2 polypeptide
(XP_001688761)
[0617] SEQ ID NO:74 Anopheles gambiae MGAT2 polypeptide
(XP_315985.3)
[0618] SEQ ID NO:75 Tribolium castaneum MGAT2 polypeptide
(XP_975146)
[0619] SEQ ID NO:76 Homo sapiens MGAT3 polypeptide (AA063579.1)
[0620] SEQ ID NO:77 Pan troglodytes MGAT3 polypeptide isoform 1
(XP_001154107.1)
[0621] SEQ ID NO:78 Pan troglodytes MGAT3 polypeptide isoform 2
(XP_001154171.1)
[0622] SEQ ID NO:79 Pan troglodytes MGAT3 isoform 3
(XP_527842.2)
[0623] SEQ ID NO:80 Canis familiaris MGAT3 polypeptide
(XP_850305.1)
[0624] SEQ ID NO:81 Bos taurus MGAT3 polypeptide (XP_875499.3)
[0625] SEQ ID NO:82 Danio rerio MGAT3 polypeptide (XP_693505.1)
[0626] SEQ ID NO:83 Arabidopsis thaliana DGAT1 polypeptide
(CAB44774.1)
[0627] SEQ ID NO:84 Arabidopsis thaliana GPAT4 polynucleotide
(NM_100043.4)
[0628] SEQ ID NO:85 Arabidopsis thaliana GPAT6 polynucleotide
(NM_129367.3)
[0629] SEQ ID NO:86 Arabidopsis thaliana GPAT polynucleotide
(AF195115.1)
[0630] SEQ ID NO:87 Arabidopsis thaliana GPAT polynucleotide
(AY062466.1)
[0631] SEQ ID NO:88 Oryza sativa GPAT polynucleotide
(AC118133.4)
[0632] SEQ ID NO:89 Picea sitchensis GPAT polynucleotide
(EF086095.1)
[0633] SEQ ID NO:90 Zea mays GPAT polynucleotide (BT067649.1)
[0634] SEQ ID NO:91 Arabidopsis thaliana GPAT polynucleotide
(AK228870.1)
[0635] SEQ ID NO:92 Oryza saliva GPAT polynucleotide
(AK241033.1)
[0636] SEQ ID NO:93 Oryza sativa GPAT polynucleotide
(CM000127.1)
[0637] SEQ ID NO:94 Oryza saliva GPAT polynucleotide
(CM000130.1)
[0638] SEQ ID NO:95 Oryza sativa GPAT polynucleotide
(CM000139.1)
[0639] SEQ ID NO:96 Oryza sativa GPAT polynucleotide
(CM000126.1)
[0640] SEQ ID NO:97 Oryza sativa GPAT polynucleotide
(CM000128.1)
[0641] SEQ ID NO:98 Oryza saliva GPAT polynucleotide
(CM000140.1)
[0642] SEQ ID NO:99 Selaginella moellendorfii GPAT polynucleotide
(GL377667.1)
[0643] SEQ ID NO: 100 Selaginella moellendorffii GPAT
polynucleotide (GL377667.1)
[0644] SEQ ID NO:101 Selaginella moellendorffii GPAT polynucleotide
(GL377648.1)
[0645] SEQ ID NO: 102 Selaginella moellendorffii GPAT
polynucleotide (GL377622.1)
[0646] SEQ ID NO:103 Selaginella moellendorffii GPAT polynucleotide
(GL377590.1)
[0647] SEQ ID NO: 104 Selaginella moellendorffii GPAT
polynucleotide (GL377576.1)
[0648] SEQ ID NO:105 Selaginella moellendorfii GPAT polynucleotide
(GL377576.1)
[0649] SEQ ID NO:106 Oryza sativa GPAT polynucleotide
(NM_001051374.2)
[0650] SEQ ID NO: 107 Oryza saliva GPAT polynucleotide
(NM_001052203.1)
[0651] SEQ ID NO: 108: Zea mays GPAT8 polynucleotide
(NM_001153970.1)
[0652] SEQ ID NO:109: Zea mays GPAT polynucleotide
(NM_001155835.1)
[0653] SEQ ID NO: 110: Zea mays GPAT polynucleotide
(NM_001174880.1)
[0654] SEQ ID NO: 111 Brassica napus GPAT4 polynucleotide
(JQ666202.1)
[0655] SEQ ID NO: 112 Arabidopsis thaliana GPAT8 polynucleotide
(NM_116264.5)
[0656] SEQ ID NO:113 Physcomitrella patens GPAT polynucleotide
(XM_001764949.1)
[0657] SEQ ID NO:114 Physcomitrella patens GPAT polynucleotide
(XM_001769619.1)
[0658] SEQ ID NO: 115 Physcomitrella patens GPAT polynucleotide
(XM_001769672.1)
[0659] SEQ ID NO:116 Physcomitrella patens GPAT polynucleotide
(XM_001771134.1)
[0660] SEQ ID NO:117 Physcomitrella patens GPAT polynucleotide
(XM_001780481.1)
[0661] SEQ ID NO: 118 Vitis vinifera GPAT polynucleotide
(XM_002268477.1)
[0662] SEQ ID NO: 119 Vitis vinifera GPAT polynucleotide
(XM_002275312.1)
[0663] SEQ ID NO:120 Vitis vinifera GPAT polynucleotide
(XM_002275996.1)
[0664] SEQ ID NO:121 Vitis vinifera GPAT polynucleotide
(XM_002279055.1)
[0665] SEQ ID NO: 122 Populus trichocarpa GPAT polynucleotide
(XM_002309088.1)
[0666] SEQ ID NO: 123 Populus trichocarpa GPAT polynucleotide
(XM_002309240.1)
[0667] SEQ ID NO: 124 Populus trichocarpa GPAT polynucleotide
(XM_002322716.1)
[0668] SEQ ID NO: 125 Populus trichocarpa GPAT polynucleotide
(XM_002323527.1)
[0669] SEQ ID NO: 126 Sorghum bicolor GPAT polynucleotide
(XM_002439842.1)
[0670] SEQ ID NO:127 Sorghum bicolor GPAT polynucleotide
(XM_002458741.1)
[0671] SEQ ID NO:128 Sorghum bicolor GPAT polynucleotide
(XM_002463871.1)
[0672] SEQ ID NO:129 Sorghum bicolor GPAT polynucleotide
(XM_002464585.1)
[0673] SEQ ID NO: 130 Ricinus communis GPAT polynucleotide
(XM_002511827.1)
[0674] SEQ ID NO:131 Ricinus communis GPAT polynucleotide
(XM_002517392.1)
[0675] SEQ ID NO: 132 Ricinus communis GPAT polynucleotide
(XM_002520125.1)
[0676] SEQ ID NO:133 Arabidopsis lyrata GPAT polynucleotide
(XM_002872909.1)
[0677] SEQ ID NO:134 Arabidopsis lyrata GPAT6 polynucleotide
(XM_002881518.1)
[0678] SEQ ID NO 135 Vernicia fordii putative GPAT8 polynucleotide
(FJ479753.1)
[0679] SEQ ID NO 136 Oryza sativa GPAT polynucleotide
(NM_001057724.1)
[0680] SEQ ID NO:137 Brassica napus GPAT4 polynucleotide
(JQ666203.1) SEQ ID NO 138 Populus trichocarpa GPAT polynucleotide
(XM_002320102.1)
[0681] SEQ ID NO:139 Sorghum bicolor GPAT polynucleotide
(XM_002451332.1)
[0682] SEQ ID NO: 140 Ricinus communis GPAT polynucleotide
(XM_002531304.1)
[0683] SEQ ID NO:141 Arabidopsis lyrata GPAT4 polynucleotide
(XM_002889315.1)
[0684] SEQ ID NO: 142 Arabidopsis thaliana GPAT1 polynucleotide
(NM_100531.2)
[0685] SEQ ID NO 143 Arabidopsis thaliana GPAT3 polynucleotide
(NM_116426.2)
[0686] SEQ ID NO: 144 Arabidopsis thaliana GPAT4 polypeptide
(NP_171667.1)
[0687] SEQ ID NO: 145 Arabidopsis thaliana GPAT6 polypeptide
(NP_181346.1)
[0688] SEQ ID NO: 146 Arabidopsis thaliana GPAT polypeptide
(AAF02784.1)
[0689] SEQ ID NO:147 Arabidopsis thaliana GPAT polypeptide
(AAL32544.1)
[0690] SEQ ID NO:148 Oryza sativa GPAT polypeptide (AAP03413.1)
[0691] SEQ ID NO: 149 Picea sitchensis GPAT polypeptide
(ABK25381.1)
[0692] SEQ ID NO:150 Zea mays GPAT polypeptide (ACN34546.1)
[0693] SEQ NO ID:151 Arabidopsis thaliana GPAT polypeptide
(BAF00762.1)
[0694] SEQ ID NO:152 Oryza sativa GPAT polypeptide (BAH00933.1)
[0695] SEQ ID NO:153 Oryza sativa GPAT polypeptide (EAY84189.1)
[0696] SEQ ID NO:154 Oryza saliva GPAT polypeptide (EAY98245.1)
[0697] SEQ ID NO:155 Oryza sativa GPAT polypeptide (EAZ21484.1)
[0698] SEQ ID NO:156 Oryza sativa GPAT polypeptide (EEC71826.1)
[0699] SEQ ID NO:157 Oryza sativa GPAT polypeptide (EEC76137.1)
[0700] SEQ ID NO:158 Oryza saliva GPAT polypeptide (EEE59882.1)
[0701] SEQ ID NO: 159 Selaginella moellendorflii GPAT polypeptide
(EFJ08963.1)
[0702] SEQ ID NO: 160 Selaginella moellendorflii GPAT polypeptide
(EFJ08964.1)
[0703] SEQ ID NO:161 Selaginella moellendorfii GPAT polypeptide
(EFJ11200.1)
[0704] SEQ ID NO:162 Selaginella moellendorfii GPAT polypeptide
(EFJ15664.1)
[0705] SEQ ID NO:163 Selaginella moellendorffii GPAT polypeptide
(EFJ24086.1)
[0706] SEQ ID NO:164 Selaginella moellendorffii GPAT polypeptide
(EFJ29816.1)
[0707] SEQ ID NO: 165 Selaginella moellendorfii GPAT polypeptide
(EFJ29817.1)
[0708] SEQ ID NO:166 Oryza saliva GPAT polypeptide
(NP_001044839.1)
[0709] SEQ ID NO:167 Oryza sativa GPAT polypeptide
(NP_001045668.1)
[0710] SEQ ID NO:168 Zea mays GPAT 8 polypeptide
(NP_001147442.1)
[0711] SEQ ID NO:169 Zea mays GPAT polypeptide (NP_001149307.1)
[0712] SEQ ID NO: 170 Zea mays protein GPAT polypeptide
(NP_001168351.1)
[0713] SEQ ID NO:171 Brassica napus GPAT4 polypeptide
(AFH02724.1)
[0714] SEQ ID NO: 172 Arabidopsis thaliana GPAT8 polypeptide
(NP_191950.2)
[0715] SEQ ID NO:173 Physcomitrella patens GPAT polypeptide
(XP_001765001.1)
[0716] SEQ ID NO: 174 Physcomitrella patens GPAT polypeptide
(XP_001769671.1)
[0717] SEQ ID NO: 175 Physcomitrella patens GPAT polypeptide
(XP_001769724.1)
[0718] SEQ ID NO: 176 Physcomitrella patens GPAT polypeptide
(XP_001771186.1)
[0719] SEQ ID NO: 177 Physcomitrella patens GPAT polypeptide
(XP_001780533.1)
[0720] SEQ ID NO:178 Vitis vinifera GPAT polypeptide
(XP_002268513.1)
[0721] SEQ ID NO: 179 Vitis vinifera GPAT polypeptide
(XP_002275348.1)
[0722] SEQ ID NO: 180 Vitis vinifera GPAT polypeptide
(XP_002276032.1)
[0723] SEQ ID NO:181 Vitis vinifera GPAT polypeptide
(XP_002279091.1)
[0724] SEQ ID NO:182 Populus trichocarpa GPAT polypeptide
(XP_002309124.1)
[0725] SEQ ID NO: 183 Populus trichocarpa GPAT polypeptide
(XP_002309276.1)
[0726] SEQ ID NO:184 Populus trichocarpa GPAT polypeptide
(XP_002322752.1)
[0727] SEQ ID NO:185 Populus trichocarpa GPAT polypeptide
(XP_002323563.1)
[0728] SEQ ID NO:186 Sorghum bicolor GPAT polypeptide
(XP_002439887.1)
[0729] SEQ ID NO: 187 Sorghum bicolor GPAT polypeptide
(XP_002458786.1)
[0730] SEQ ID NO:188 Sorghum bicolor GPAT polypeptide
(XP_002463916.1)
[0731] SEQ ID NO:189 Sorghum bicolor GPAT polypeptide
(XP_002464630.1)
[0732] SEQ ID NO:190 Ricinus communis GPAT polypeptide
(XP_002511873.1)
[0733] SEQ ID NO:191 Ricinus communis GPAT polypeptide
(XP_002517438.1)
[0734] SEQ ID NO:192 Ricinus communis GPAT polypeptide
(XP_002520171.1)
[0735] SEQ ID NO:193 Arabidopsis lyrata GPAT polypeptide
(XP_002872955.1)
[0736] SEQ ID NO: 194 Arabidopsis lyrata GPAT6 polypeptide
(XP_002881564.1)
[0737] SEQ ID NO:195 Vernicia fordii GPAT polypeptide
(ACT32032.1)
[0738] SEQ ID NO:196 Oryza saliva GPAT polypeptide
(NP_001051189.1)
[0739] SEQ ID NO:197 Brassica napus GPAT4 polypeptide
(AFH02725.1)
[0740] SEQ ID NO:198 Populus trichocarpa GPAT polypeptide
(XP_002320138.1)
[0741] SEQ ID NO:199 Sorghum bicolor GPAT polypeptide
(XP_002451377.1)
[0742] SEQ ID NO:200 Ricinus communis GPAT polypeptide
(XP_002531350.1)
[0743] SEQ ID NO:201 Arabidopsis lyrata GPAT4 polypeptide
(XP_002889361.1)
[0744] SEQ ID NO:202 Arabidopsis thaliana GPAT1 polypeptide
(NP_563768.1)
[0745] SEQ ID NO:203 Arabidopsis thaliana GPAT3 polypeptide
(NP_192104.1)
[0746] SEQ ID NO:204 Arabidopsis thaliana DGAT2 polynucleotide
(NM_115011.3)
[0747] SEQ ID NO:205 Ricinus communis DGAT2 polynucleotide
(AY916129.1)
[0748] SEQ ID NO:206 Vernicia fordii DGAT2 polynucleotide
(DQ356682.1)
[0749] SEQ ID NO:207 Mortierella ramanniana DGAT2 polynucleotide
(AF391089.1)
[0750] SEQ ID NO:208 Homo sapiens DGAT2 polynucleotide
(NM_032564.1)
[0751] SEQ ID NO:209 Homo sapiens DGAT2 polynucleotide
(NM_001013579.2)
[0752] SEQ ID NO:210 Bos taurus DGAT2 polynucleotide
(NM_205793.2)
[0753] SEQ ID NO:211 Mus musculus DGAT2 polynucleotide
(AF384160.1)
[0754] SEQ ID NO:212 Arabidopsis thaliana DGAT2 polypeptide
(NP_566952.1)
[0755] SEQ ID NO:213 Ricinus communis DGAT2 polypeptide
(AAY16324.1)
[0756] SEQ ID NO:214 Vernicia fordii DGAT2 polypeptide
(ABC94474.1)
[0757] SEQ ID NO:215 Mortierella ramanniana DGAT2 polypeptide
(AAK84179.1)
[0758] SEQ ID NO:216 Homo sapiens DGAT2 polypeptide (Q96PD7.2)
[0759] SEQ ID NO:217 Homo sapiens DGAT2 polypeptide (Q58HT5.1)
[0760] SEQ ID NO:218 Bos taurus DGAT2 polypeptide (Q70VZ8.1)
[0761] SEQ ID NO:219 Mus musculus DGAT2 polypeptide
(AAK84175.1)
[0762] SEQ ID NO:220 YFP tripeptide--conserved DGAT2 and/or MGAT1/2
sequence motif
[0763] SEQ ID NO:221 HPHG tetrapeptide--conserved DGAT2 and/or
MGAT1/2 sequence motif
[0764] SEQ ID NO:222 EPHS tetrapeptide--conserved plant DGAT2
sequence motif
[0765] SEQ ID NO:223 RXGFX(K/R)XAXXXGXXX(L/V)VPXXXFG(E/Q)--long
conserved sequence motif of DGAT2 which is part of the putative
glycerol phospholipid domain
[0766] SEQ ID NO:224 FLXLXXXN--conserved sequence motif of mouse
DGAT2 and MGAT1/2 which is a putative neutral lipid binding
domain
[0767] SEQ ID NO:225 plsC acyltransferase domain (PF01553) of
GPAT
[0768] SEQ ID NO:226 HAD-like hydrolase (PF12710) superfamily
domain of GPAT
[0769] SEQ ID NO:227 Phosphoserine phosphatase domain (PF00702).
GPAT4-8 contain a N-terminal region homologous to this domain
[0770] SEQ ID NO:228 Conserved GPAT amino acid sequence
GDLVICPEGTTCREP
[0771] SEQ ID NO:229 Conserved GPAT/phosphatase amino acid sequence
(Motif I)
[0772] SEQ ID NO:230 Conserved GPAT/phosphatase amino acid sequence
(Motif III)
[0773] SEQ ID NO:231 Arabidopsis thaliana WRI1 polynucleotide
(NM_202701.2)
[0774] SEQ ID NO:232 Arabidopsis thaliana WRI1 polynucleotide
(NM_001035780.2)
[0775] SEQ ID NO:233 Arabidopsis thaliana WRI1 polynucelotide
(NM_115292.4)
[0776] SEQ ID NO:234 Arabidopsis lyrata subsp. lyrala
polynucleotide (XM_002876205.1)
[0777] SEQ ID NO:235 Brassica napus WRI1 polynucelotide
(DQ370141.1)
[0778] SEQ ID NO:236 Brassica napus WRI1 polynucleotide
(HM370542.1)
[0779] SEQ ID NO:237 Glycine max WRI1polynucelotide
(XM_003530322.1)
[0780] SEQ ID NO:238 Jatropha curcas WRI1 polynucleotide
(JF703666.1)
[0781] SEQ ID NO:239 Ricinus communis WRI1 polynucleotide
(XM_002525259.1)
[0782] SEQ ID NO:240 Populus tichocarpa WRI1 polynucleotide
(XM_002316423.1)
[0783] SEQ ID NO:241 Brachypodium distachyon WRI1polynucleotide
(XM_003578949.1)
[0784] SEQ ID NO:242 Hordeum vulgare subsp. vulgare WRI1
polynucleotide (AK355408.1)
[0785] SEQ ID NO:243 Sorghum bicolor WRI1 polynucelotide
(XM_002450149.1)
[0786] SEQ ID NO:244 Zea mays WRI1 polynucleotide (EU960249.1)
[0787] SEQ ID NO:245 Brachypodium distachyon WRI1 polynucelotide
(XM_003561141.1)
[0788] SEQ ID NO:246 Sorghum bicolor WRI1 polynucleotide
(XM_002437774.1)
[0789] SEQ ID NO:247 Sorghum bicolor WRI1 polynucleotide
(XM_002441399.1)
[0790] SEQ ID NO:248 Glycine max WRI1 polynucleotide
(XM_003530638.1)
[0791] SEQ ID NO:249 Glycine max WRI1 polynucleotide
(XM_003553155.1)
[0792] SEQ ID NO:250 Populus trichocarpa WRI1 polynucleotide
(XM_002315758.1)
[0793] SEQ ID NO:251 Vitis vinifera WRI1 polynucleotide
(XM_002270113.1)
[0794] SEQ ID NO:252 Glycine max WRI1 polynucleotide
(XM_003533500.1)
[0795] SEQ ID NO:253 Glycine max WRI1 polynucleotide
(XM_003551675.1)
[0796] SEQ ID NO:254 Medicago truncatula WRI1 polynucleotide
(XM_003621069.1)
[0797] SEQ ID NO:255 Populus trichocarpa WRI1 polynucleotide
(XM_002323800.1)
[0798] SEQ ID NO:256 Ricinus communis WRI1 polynucleotide
(XM_002517428.1)
[0799] SEQ ID NO:257 Brachypodium distachyon WRI1 polynucleotide
(XM_003572188.1)
[0800] SEQ ID NO:258 Sorghum bicolor WRI1 polynucleotide
(XM_002444384.1)
[0801] SEQ ID NO:259 Zea mays WRI1 polynucleotide
(NM_001176888.1)
[0802] SEQ ID NO:260 Arabidopsis lyrata subsp. lyrata WRI1
polynucleotide (XM_002889219.1)
[0803] SEQ ID NO:261 Arabidopsis thaliana WRI1 polynucleotide
(NM_106619.3)
[0804] SEQ ID NO:262 Arabidopsis lyrata subsp. lyrata WRI1
polynucleotide (XM_002890099.1)
[0805] SEQ ID NO:263 Thellungiella halophila WRI1 polynucleotide
(AK352786.1)
[0806] SEQ ID NO:264 Arabidopsis thaliana WRI1 polynucleotide
(NM_101474.2)
[0807] SEQ ID NO:265 Glycine max WRI1 polynucleotide
(XM_003530302.1)
[0808] SEQ ID NO:266 Brachypodium distachyon WRI1 polynucleotide
(XM_003578094.1)
[0809] SEQ ID NO:267 Sorghum bicolor WRI1 polynucleotide
(XM_002460191.1)
[0810] SEQ ID NO:268 Zea mays WRI1 polynucleotide
(NM_001152866.1)
[0811] SEQ ID NO:269 Glycine max WRI1 polynucleotide
(XM_003519119.1)
[0812] SEQ ID NO:270 Glycine max WRI1 polynucleotide
(XM_003550628.1)
[0813] SEQ ID NO:271 Medicago truncatula WRI1 polynucleotide
(XM_003610213.1)
[0814] SEQ ID NO:272 Glycine max WRI1 polynucleotide
(XM_003523982.1)
[0815] SEQ ID NO:273 Glycine max WRI1 polynucleotide
(XM_003525901.1)
[0816] SEQ ID NO:274 Populus trichocarpa WRI1 polynucleotide
(XM_002325075.1)
[0817] SEQ ID NO:275 Vitis vinifera WRI1 polynucleotide
(XM_002273010.2)
[0818] SEQ ID NO:276 Populus trichocarpa WRI1 polynucleotide
(XM_002303830.1)
[0819] SEQ ID NO:277 Lupinis angustifolius WRI1 polynucleotide,
partial sequence (NA-080818_Plate14f06.b1)
[0820] SEQ ID NO:278 Lupinis angustifolius WRI1 polynucleotide
[0821] SEQ ID NO:279 Arabidopsis thaliana WRI1 polypeptide
(A8MS57)
[0822] SEQ ID NO:280 Arabidopsis thaliana WRI1 polypeptide
(Q6X5Y6)
[0823] SEQ ID NO:281 Arabidopsis lyrata subsp. lyrata WRI1
polypeptide (XP_002876251.1)
[0824] SEQ ID NO:282 Brassica napus WRI1 polypepetide
(ABD16282.1)
[0825] SEQ ID NO:283 Brassica napus WRI1 polyppetide
(ADO16346.1)
[0826] SEQ ID NO:284 Glycine max WRI1 polypeptide
(XP_003530370.1)
[0827] SEQ ID NO:285 Jatropha curcas WRI1 polypeptide
(AE022131.1)
[0828] SEQ ID NO:286 Ricinus communis WRI1 polypeptide
(XP_002525305.1)
[0829] SEQ ID NO:287 Populus trichocarpa WRI1 polypeptide
(XP_002316459.1)
[0830] SEQ ID NO:288 Vitis vinifera WRI1 polypeptide
(CBI29147.3)
[0831] SEQ ID NO:289 Brachypodium distachyon WRI1 polypeptide
(XP_003578997.1)
[0832] SEQ ID NO:290 Hordeum vulgare subsp. vulgare WRI1
polypeptide (BAJ86627.1)
[0833] SEQ ID NO:291 Oryza sativa WRI1 polypeptide (EAY79792.1)
[0834] SEQ ID NO:292 Sorghum bicolor WRI1 polypeptide
(XP_002450194.1)
[0835] SEQ ID NO:293 Zea mays WRI1 polypeptide (ACG32367.1)
[0836] SEQ ID NO:294 Brachypodium distachyon WRI1 polypeptide
(XP_003561189.1)
[0837] SEQ ID NO:295 Brachypodium sylvaticum WRI1 polypeptide
(ABL85061.1)
[0838] SEQ ID NO:296 Oryza sativa WRI1 polypeptide (BAD68417.1)
[0839] SEQ ID NO:297 Sorghum bicolor WRI1 polypeptide
(XP_002437819.1)
[0840] SEQ ID NO:298 Sorghum bicolor WRI1 polypeptide
(XP_002441444.1)
[0841] SEQ ID NO:299 Glycine max WRI1 polypeptide
(XP_003530686.1)
[0842] SEQ ID NO:300 Glycine max WRI1 polypeptide
(XP_003553203.1)
[0843] SEQ ID NO:301 Populus trichocarpa WRI1 polypeptide
(XP_002315794.1)
[0844] SEQ ID NO:302 Vitis vinifera WRI1 polypeptide
(XP_002270149.1)
[0845] SEQ ID NO:303 Glycine max WRI1 polypeptide
(XP_003533548.1)
[0846] SEQ ID NO:304 Glycine max WRI1 polypeptide
(XP_003551723.1)
[0847] SEQ ID NO:305 Medicago truncatula WRI1 polypeptide
(XP_003621117.1)
[0848] SEQ ID NO:306 Populus trichocarpa WRI1 polypeptide
(XP_002323836.1)
[0849] SEQ ID NO:307 Ricinus communis WRI1 polypeptide
(XP_002517474.1)
[0850] SEQ ID NO:308 Vitis vinifera WRI1 polypeptide
(CAN79925.1)
[0851] SEQ ID NO:309 Brachypodium distachyon WRI1 polypeptide
(XP_003572236.1)
[0852] SEQ ID NO:310 Oryza saliva WRI1 polypeptide (BAD10030.1)
[0853] SEQ ID NO:311 Sorghum bicolorWRI1 polypeptide
(XP_002444429.1)
[0854] SEQ ID NO:312 Zea mays WRI1 polypeptide (NP_001170359.1)
[0855] SEQ ID NO:313 Arabidopsis lyrata subsp. lyrata WRI1
polypeptide (XP_002889265.1)
[0856] SEQ ID NO:314 Arabidopsis thaliana WRI1 polypeptide
(AAF68121.1)
[0857] SEQ ID NO:315 Arabidopsis thaliana WRI1 polypeptide
(NP_178088.2)
[0858] SEQ ID NO:316 Arabidopsis lyrata subsp. lyrata WRI1
polypeptide (XP_002890145.1)
[0859] SEQ ID NO:317 Thellungiella halophila WRI1 polypeptide
(BAJ33872.1)
[0860] SEQ ID NO:318 Arabidopsis thaliana WRI1 polypeptide
(NP_563990.1)
[0861] SEQ ID NO:319 Glycine max WRI1 polypeptide
(XP_003530350.1)
[0862] SEQ ID NO:320 Brachypodium distachyon WRI1 polypeptide
(XP_003578142.1)
[0863] SEQ ID NO:321 Oryza saliva WRI1 polypeptide (EAZ09147.1)
[0864] SEQ ID NO:322 Sorghum bicolor WRI1 polypeptide
(XP_002460236.1)
[0865] SEQ ID NO:323 Zea mays WRI1 polypeptide (NP_001146338.1)
[0866] SEQ ID NO:324 Glycine max WRI1 polypeptide
(XP_003519167.1)
[0867] SEQ ID NO:325 Glycine max WRI1 polypeptide
(XP_003550676.1)
[0868] SEQ ID NO:326 Medicago truncatula WRI1 polypeptide
(XP_003610261.1)
[0869] SEQ ID NO:327 Glycine max WRI1 polypeptide
(XP_003524030.1)
[0870] SEQ ID NO:328 Glycine max WRI1 polypeptide
(XP_003525949.1)
[0871] SEQ ID NO:329 Populus trichocarpa WRI1 polypeptide
(XP_002325111.1)
[0872] SEQ ID NO:330 Vitis vinifera WRI1 polypeptide
(CBI36586.3)
[0873] SEQ ID NO:331 Vitis vinifera WRI1 polypeptide
(XP_002273046.2)
[0874] SEQ ID NO:332 Populus trichocarpa WRI1 polypeptide
(XP_002303866.1)
[0875] SEQ ID NO:333 Vitis vinifera WRI1 polypeptide
(CBI25261.3)
[0876] SEQ ID NO:334 Sorbi-WRL1
[0877] SEQ ID NO: 335 Lupan-WRL1
[0878] SEQ ID NO:336 Ricco-WRL1
[0879] SEQ ID NO:337 Lupin angustifolius WRI1 polypeptide
[0880] SEQ ID NO:338 Aspergillus fumigatus DGAT polynucleotide
(XM_750079.1)
[0881] SEQ ID NO:339 Ricinus communis DGAT polynucleotide
(AY366496.1)
[0882] SEQ ID NO:340 Vernicia fordii DGAT1 polynucleotide
(DQ356680.1)
[0883] SEQ ID NO:341 Vernonia galamensis DGAT1 polynucleotide
(EF653276.1)
[0884] SEQ ID NO:342 Vernonia galamensis DGAT1 polynucleotide
(EF653277.1)
[0885] SEQ ID NO:343 Euonymus alatus DGAT1 polynucelotide
(AY751297.1)
[0886] SEQ ID NO:344 Caenorhabditis elegans DGAT1 polynucelotide
(AF221132.1)
[0887] SEQ ID NO:345 Rattus norvegicus DGAT1 polynucelotide
(NM_053437.1)
[0888] SEQ ID NO:346 Homo sapiens DGAT1polynucleotide
(NM_012079.4)
[0889] SEQ ID NO:347 Aspergillus fumigatus DGAT1 polypeptide
(XP_755172.1)
[0890] SEQ ID NO:348 Ricinus communis DGAT1 polypeptide
(AAR11479.1)
[0891] SEQ ID NO:349 Vernicia fordii DGAT1 polypeptide
(ABC94472.1)
[0892] SEQ ID NO:350 Vernonia galamensis DGAT1 polypeptide
(ABV21945.1)
[0893] SEQ ID NO:351 Vernonia galamensis DGAT1 polypeptide
(ABV21946.1)
[0894] SEQ ID NO:352 Euonymus alatus DGAT1 polypeptide
(AAV31083.1)
[0895] SEQ ID NO:353 Caenorhabditis elegans DGAT1 polypeptide
(AAF82410.1)
[0896] SEQ ID NO:354 Rattus norvegicus DGAT1 polypeptide
(NP_445889.1)
[0897] SEQ ID NO:355 Homo sapiens DGAT1 polypeptide
(NP_036211.2)
[0898] SEQ ID NO:356 WRI1 motif (R G V T/S R H R W T G R)
[0899] SEQ ID NO:357 WRI1 motif (F/Y E A H L W D K)
[0900] SEQ ID NO:358 WRI1 motif (D L A A L K Y W G)
[0901] SEQ ID NO:359 WRI1 motif (S X G F S/A R G X)
[0902] SEQ ID NO:360 WRI1 motif (H H H/Q N G R/K W E A R I G R/K
V)
[0903] SEQ ID NO:361 WRI1 motif (Q E E A A A X Y D)
[0904] SEQ ID NO:362 Brassica napus oleosin polypeptide
(CAA57545.1)
[0905] SEQ ID NO:363 Brassica napus oleosin S1-1 polypeptide
(ACG69504.1)
[0906] SEQ ID NO:364 Brassica napus oleosin S2-1 polypeptide
(ACG69503.1)
[0907] SEQ ID NO:365 Brassica napus oleosin S3-1 polypeptide
(ACG69513.1)
[0908] SEQ ID NO:366 Brassica napus oleosin S4-1 polypeptide
(ACG69507.1)
[0909] SEQ ID NO:367 Brassica napus oleosin S5-1 polypeptide
(ACG69511.1)
[0910] SEQ ID NO:368 Arachis hypogaea oleosin 1 polypeptide
(AAZ20276.1)
[0911] SEQ ID NO:369 Arachis hypogaea oleosin 2 polypeptide
(AAU21500.1)
[0912] SEQ ID NO:370 Arachis hypogaea oleosin 3 polypeptide
(AAU21501.1)
[0913] SEQ ID NO:371 Arachis hypogaea oleosin 5 polypeptide
(ABC96763.1)
[0914] SEQ ID NO:372 Ricinus communis oleosin 1 polypeptide
(EEF40948.1)
[0915] SEQ ID NO:373 Ricinus communis oleosin 2 polypeptide
(EEF51616.1)
[0916] SEQ ID NO:374 Glycine max oleosin isoform a polypeptide
(P29530.2)
[0917] SEQ ID NO:375 Glycine max oleosin isoform b polypeptide
(P29531.1)
[0918] SEQ ID NO:376 Linum usitatissimum oleosin low molecular
weight isoform polypeptide (ABB01622.1)
[0919] SEQ ID NO:377 amino acid sequence of Linum usitatissimum
oleosin high molecular weight isoform polypeptide (ABB01624.1)
[0920] SEQ ID NO:378 Helianthus annuus oleosin polypeptide
(CAA44224.1)
[0921] SEQ ID NO:379 Zea mays oleosin polypeptide
(NP_001105338.1)
[0922] SEQ ID NO:380 Brassica napus steroleosin polypeptide
(ABM30178.1)
[0923] SEQ ID NO:381 Brassica napus steroleosin SLO1-1 polypeptide
(ACG69522.1)
[0924] SEQ ID NO:382 Brassica napus steroleosin SLO2-1 polypeptide
(ACG69525.1)
[0925] SEQ ID NO:383 Sesamum indicum steroleosin polypeptide
(AAL13315.1)
[0926] SEQ ID NO:384 Zea mays steroleosin polypeptide
(NP_001152614.1)
[0927] SEQ ID NO:385 Brassica napus caleosin CLO-1 polypeptide
(ACG69529.1)
[0928] SEQ ID NO:386 Brassica napus caleosin CLO-3 polypeptide
(ACG69527.1)
[0929] SEQ ID NO:387 Sesamum indicum caleosin polypeptide
(AAF13743.1)
[0930] SEQ ID NO:388 Zea mays caleosin polypeptide
(NP_001151906.1)
[0931] SEQ ID NO:389 Brassica napus oleosin polynucleotide
(X82020.1)
[0932] SEQ ID NO:390 Brassica napus oleosin S1-1 polynucleotide
(EU678256.1)
[0933] SEQ ID NO:391 Brassica napus oleosin S2-1 polynucleotide
(EU678255.1)
[0934] SEQ ID NO:392 Brassica napus oleosin S3-1 polynucleotide
(EU678265.1)
[0935] SEQ ID NO:393 Brassica napus oleosin S4-1 polynucleotide
(EU678259.1)
[0936] SEQ ID NO:394 Brassica napus oleosin S5-1 polynucleotide
(EU678263.1)
[0937] SEQ ID NO:395 Arachis hypogaea oleosin 1 polynucleotide
(DQ097716.1)
[0938] SEQ ID NO:396 Arachis hypogaea oleosin 2 polynucleotide
(AY722695.1)
[0939] SEQ ID NO:397 Arachis hypogaea oleosin 3 polynucleotide
(AY722696.1)
[0940] SEQ ID NO:398 Arachis hypogaea oleosin 5 polynucleotide
(DQ368496.1)
[0941] SEQ ID NO:399 Helianthus annuus oleosin polynucleotide
(X62352.1)
[0942] SEQ ID NO:400 Zea mays oleosin polynucleotide
(NM_001111868.1)
[0943] SEQ ID NO:401 Brassica napus steroleosin polynucleotide
(EF143915.1)
[0944] SEQ ID NO:402 Brassica napus steroleosin SLO1-1
polynucleotide (EU678274.1)
[0945] SEQ ID NO:403 Brassica napus steroleosin SLO2-1
polynucleotide (EU678277.1)
[0946] SEQ ID NO:404 Zea mays steroleosin polynucleotide
(NM_001159142.1)
[0947] SEQ ID NO:405 Brassica napus caleosin CLO-1 polynucleotide
(EU678281.1)
[0948] SEQ ID NO:406 Brassica napus caleosin CLO-3 polynucleotide
(EU678279.1)
[0949] SEQ ID NO:407 Sesamum indicum caleosin polynucleotide
(AF109921.1)
[0950] SEQ ID NO:408 Zea mays caleosin polynucleotide
(NM_001158434.1)
[0951] SEQ ID NO:409 pJP3502 entire vector sequence
(three-gene)
[0952] SEQ ID NO:410 pJP3503 entire vector sequence (four-gene)
[0953] SEQ ID NO:411 pJP3502 TDNA (inserted into genome)
sequence
[0954] SEQ ID NO:412 pJP3503 TDNA (inserted into genome)
sequence
[0955] SEQ ID NO:413 pJP3507 vector sequence
[0956] SEQ ID NO:414 Linker sequence
[0957] SEQ ID NO:415 Soybean Synergy
[0958] SEQ ID NO:416 12ABFJYC_pJP3569_insert
[0959] SEQ ID NO:417 Partial N. benthamiana CGI-58 sequence
selected for hpRNAi silencing (pTV46)
[0960] SEQ ID NO:418 Partial N. tabacum AGPase sequence selected
for hpRNAi silencing (pTV35)
[0961] SEQ ID NO:419 GXSXG lipase motif
[0962] SEQ ID NO:420 HX(4)D acyltransferase motif
[0963] SEQ ID NO:421 VX(3)HGF probable lipid binding motif
[0964] SEQ ID NO:422 Arabidopsis thaliana CGi58 polynucleotide
(NM_118548.1)
[0965] SEQ ID NO:423: Brachypodium distachyon CGi58 polynucleotide
(XM_003578402.1)
[0966] SEQ ID NO:424 Glycine max CGi58 polynucleotide
(XM_003523590.1)
[0967] SEQ ID NO:425 Zea mays CGi58 polynucleotide
(NM_001155541.1)
[0968] SEQ ID NO:426 Sorghum bicolor CGi58 polynucleotide
(XM_002460493.1)
[0969] SEQ ID NO:427 Ricinus communis CGi58 polynucleotide
(XM_002510439.1)
[0970] SEQ ID NO:428 Medicago truncatula CGi58 polynucleotide
(XM_003603685.1)
[0971] SEQ ID NO:429 Arabidopsis thaliana CGi58 polypeptide
(NP_194147.2)
[0972] SEQ ID NO:430 Brachypodium distachyon CGi58 polypeptide
(XP_003578450.1)
[0973] SEQ ID NO:431 Glycine max CGi58 polypeptide
(XP_003523638.1)
[0974] SEQ ID NO:432 Zea Mays CGi58 polypeptide
(NP_001149013.1)
[0975] SEQ ID NO:433 Sorghum bicolor CGi58 polypeptide
(XP_002460538.1)
[0976] SEQ ID NO:434 Ricinus communis CGi58 polypeptide
(XP_002510485.1)
[0977] SEQ ID NO:435 Medicago truncatula CGi58 polypeptide
(XP_003603733.1)
[0978] SEQ ID NO:436 Oryza sativa CGi58 polypeptide
(EAZ09782.1)
[0979] SEQ ID NO:437 Arabidopsis thaliana LEC2 polynucleotide
(NM_102595.2)
[0980] SEQ ID NO:438 Medicago truncatula LEC2 polynucelotide
(X60387.1)
[0981] SEQ ID NO:439 Brassica napus LEC2 polynucelotide
(HM370539.1)
[0982] SEQ ID NO:440 Arabidopsis thaliana BBM polynucleotide
(NM_121749.2)
[0983] SEQ ID NO:441 Medicago truncatula BBM polynucleotide
(AY899909.1)
[0984] SEQ ID NO:442 Arabidopsis thaliana LEC2 polypeptide
(NP_564304.1)
[0985] SEQ ID NO:443 Medicago truncatula LEC2 polypeptide
(CAA42938.1)
[0986] SEQ ID NO:444 Brassica napus LEC2 polypeptide
(ADO16343.1)
[0987] SEQ ID NO:445 Arabidopsis thaliana BBM polypeptide
(NP_197245.2)
[0988] SEQ ID NO:446 Medicago truncatula BBM polypeptide
(AAW82334.1)
[0989] SEQ ID NO:447 Inducible Aspergillus niger alcA promoter
[0990] SEQ ID NO:448 AlcR inducer that activates the AlcA promotor
in the presence of ethanol
DETAILED DESCRIPTION OF THE INVENTION
General Techniques and Definitions
[0991] Unless specifically defined otherwise, all technical and
scientific terms used herein shall be taken to have the same
meaning as commonly understood by one of ordinary skill in the art
(e.g., in cell culture, molecular genetics, immunology,
immunohistochemistry, protein chemistry, lipid and fatty acid
chemistry, biofeul production, and biochemistry).
[0992] Unless otherwise indicated, the recombinant protein, cell
culture, and immunological techniques utilized in the present
invention are standard procedures, well known to those skilled in
the art. Such techniques are described and explained throughout the
literature in sources such as, J. Perbal, A Practical Guide to
Molecular Cloning, John Wiley and Sons (1984), J. Sambrook et al.,
Molecular Cloning: A Laboratory Manual, Cold Spring Harbour
Laboratory Press (1989), T. A. Brown (editor), Essential Molecular
Biology: A Practical Approach, Volumes 1 and 2, IRL Press (1991),
D. M. Glover and B. D. Hames (editors), DNA Cloning: A Practical
Approach, Volumes 1-4, IRL Press (1995 and 1996), F. M. Ausubel et
al. (editors), Current Protocols in Molecular Biology, Greene Pub.
Associates and Wiley-Interscience (1988, including all updates
until present), Ed Harlow and David Lane (editors) Antibodies: A
Laboratory Manual, Cold Spring Harbour Laboratory, (1988), and J.
E. Coligan et al. (editors) Current Protocols in Immunology, John
Wiley & Sons (including all updates until present).
Selected Definitions
[0993] The term "transgenic non-human organism" refers to, for
example, a whole plant, alga, non-human animal, or an organism
suitable for fermentation such as a yeast or fungus, comprising an
exogenous polynucleotide (transgene) or an exogenous polypeptide.
In an embodiment, the transgenic non-human organism is not an
animal or part thereof. In one embodiment, the transgenic non-human
organism is a phototrophic organism (for example, a plant or alga)
capable of obtaining energy from sunlight to synthesize organic
compounds for nutrition. In another embodiment, the transgenic
non-human organism is a photosyntheic bacterium.
[0994] The term "exogenous" in the context of a polynucleotide or
polypeptide refers to the polynucleotide or polypeptide when
present in a cell which does not naturally comprise the
polynucleotide or polypeptide. Such a cell is referred to herein as
a "recombinant cell" or a "transgenic cell". In an embodiment, the
exogenous polynucleotide or polypeptide is from a different genus
to the cell comprising the exogenous polynucleotide or polypeptide.
In another embodiment, the exogenous polynucleotide or polypeptide
is from a different species. In one embodiment the exogenous
polynucleotide or polypeptide is expressed in a host plant or plant
cell and the exogenous polynucleotide or polypeptide is from a
different species or genus. The exogenous polynucleotide or
polypeptide may be non-naturally occurring, such as for example, a
synthetic DNA molecule which has been produced by recombinant DNA
methods. The DNA molecule may, often preferably, include a protein
coding region which has been codon-optimised for expression in the
cell, thereby producing a polypeptide which has the same amino acid
sequence as a naturally occurring polypeptide, even though the
nucleotide sequence of the protein coding region is non-naturally
occurring. The exogenous polynucleotide may encode, or the
exogenous polypeptide may be: a diacylglycerol acyltransferase
(DGAT) such as a DGAT1 or a DGAT2, a glycerol-3-phosphate
acyltransferase (GPAT) such as a GPAT which is capable of
synthesising MAG, a Wrinkled 1 (WRI1) transcription factor, an
Oleosin, or a silencing suppressor polypeptide. In one embodiment,
the exogenous polypeptide is an exogenous MGAT such as an MGAT1 or
an MGAT2.
[0995] As used herein, the term "extracted lipid" refers to a
composition extracted from a transgenic organism or part thereof
which comprises at least 60% (w/w) lipid.
[0996] As used herein, the term "non-polar lipid" refers to fatty
acids and derivatives thereof which are soluble in organic solvents
but insoluble in water. The fatty acids may be free fatty acids
and/or in an esterified form. Examples of esterified forms include,
but are not limited to, triacylglycerol (TAG), diacylyglycerol
(DAG), monoacylglycerol (MAG). Non-polar lipids also include
sterols, sterol esters and wax esters. Non-polar lipids are also
known as "neutral lipids". Non-polar lipid is typically a liquid at
room temperature. Preferably, the non-polar lipid predominantly
(>50%) comprises fatty acids that are at least 16 carbons in
length. More preferably, at least 50% of the total fatty acids in
the non-polar lipid are C18 fatty acids for example, oleic acid. In
an embodiment, at least 50%, more preferably at least 70%, more
preferably at least 80%, more preferably at least 90%, more
preferably at least 91%, more preferably at least 92%, more
preferably at least 93%, more preferably at least 94%, more
preferably at least 95%, more preferably at least 96%, more
preferably at least 97%, more preferably at least 98%, more
preferably at least 99% of the fatty acids in non-polar lipid of
the invention can be found as TAG. The non-polar lipid may be
further purified or treated, for example by hydrolysis with a
strong base to release the free fatty acid, or by fractionation,
distillation, or the like. Non-polar lipid may be present in or
obtained from plant parts such as seed, leaves or fruit, from
recombinant cells or from non-human organisms such as yeast.
Non-polar lipid of the invention may form part of "seedoil" if it
is obtained from seed. The free and esterified sterol (for example,
sitosterol, campesterol, stigmasterol, brassicasterol,
A5-avenasterol, sitostanol, campestanol, and cholesterol)
concentrations in the extracted lipid may be as described in
Phillips et al., 2002. Sterols in plant oils are present as free
alcohols, esters with fatty acids (esterified sterols), glycosides
and acylated glycosides of sterols. Sterol concentrations in
naturally occurring vegetable oils (seedoils) ranges up to a
maximum of about 1100 mg/100 g. Hydrogenated palm oil has one of
the lowest concentrations of naturally occurring vegetable oils at
about 60 mg/100 g. The recovered or extracted seedoils of the
invention preferably have between about 100 and about 1000 mg total
sterol/100 g of oil. For use as food or feed, it is preferred that
sterols are present primarily as free or esterified forms rather
than glycosylated forms. In the seedoils of the present invention,
preferably at least 50% of the sterols in the oils are present as
esterified sterols, except for soybean seedoil which has about 25%
of the sterols esterified. The canola seedoil and rapeseed oil of
the invention preferably have between about 500 and about 800 mg
total sterol/100 g, with sitosterol the main sterol and campesterol
the next most abundant. The corn seedoil of the invention
preferably has between about 600 and about 800 mg total sterol/100
g, with sitosterol the main sterol. The soybean seedoil of the
invention preferably has between about 150 and about 350 mg total
sterol/100 g, with sitosterol the main sterol and stigmasterol the
next most abundant, and with more free sterol than esterified
sterol. The cottonseed oil of the invention preferably has between
about 200 and about 350 mg total sterol/100 g, with sitosterol the
main sterol. The coconut oil and palm oil of the invention
preferably have between about 50 and about 100 mg total sterol/100
g, with sitosterol the main sterol. The safflower seedoil of the
invention preferably has between about 150 and about 250 mg total
sterol/100 g, with sitosterol the main sterol. The peanut seedoil
of the invention preferably has between about 100 and about 200 mg
total sterol/100 g, with sitosterol the main sterol. The sesame
seedoil of the invention preferably has between about 400 and about
600 mg total sterol/100 g, with sitosterol the main sterol. The
sunflower seedoil of the invention preferably has between about 200
and 400 mg total sterol/100 g, with sitosterol the main sterol.
Oils obtained from vegetative plant parts according to the
invention preferably have less than 200 mg total sterol/100 g, more
preferably less than 100 mg total sterol/100 g, and most preferably
less than 50 mg total sterols/100 g, with the majority of the
sterols being free sterols.
[0997] As used herein, the term "seedoil" refers to a composition
obtained from the seed/grain of a plant which comprises at least
60% (w/w) lipid, or obtainable from the seed/grain if the seedoil
is still present in the seed/grain. That is, seedoil of the
invention includes seedoil which is present in the seed/grain or
portion thereof, as well as seedoil which has been extracted from
the seed/grain. The seedoil is preferably extracted seedoil.
Seedoil is typically a liquid at room temperature. Preferably, the
total fatty acid (TFA) content in the seedoil predominantly
(>50%) comprises fatty acids that are at least 16 carbons in
length. More preferably, at least 50% of the total fatty acids in
the seedoil are C18 fatty acids for example, oleic acid. The fatty
acids are typically in an esterified form such as for example, TAG,
DAG, acyl-CoA or phospholipid. The fatty acids may be free fatty
acids and/or in an esterified form. In an embodiment, at least 50%,
more preferably at least 70%, more preferably at least 80%, more
preferably at least 90%, more preferably at least 91%, more
preferably at least 92%, more preferably at least 93%, more
preferably at least 94%, more preferably at least 95%, more
preferably at least 96%, more preferably at least 97%, more
preferably at least 98%, more preferably at least 99% of the fatty
acids in seedoil of the invention can be found as TAG. In an
embodiment, seedoil of the invention is "substantially purified" or
"purified" oil that has been separated from one or more other
lipids, nucleic acids, polypeptides, or other contaminating
molecules with which it is associated in the seed or in a crude
extract. It is preferred that the substantially purified seedoil is
at least 60% free, more preferably at least 75% free, and more
preferably, at least 90% free from other components with which it
is associated in the seed or extract. Seedoil of the invention may
further comprise non-fatty acid molecules such as, but not limited
to, sterols. In an embodiment, the seedoil is canola oil (Brassica
sp. such as Brassica carinata, Brassica juncea, Brassica
napobrassica, Brassica napus) mustard oil (Brassica juncea), other
Brassica oil (e.g., Broassica napobrassica, Brassica camelina),
sunflower oil (Helianthus sp. such as Helianthus annuus), linseed
oil (Linum usitatissimum), soybean oil (Glycine max), safflower oil
(Carthamus tinclorius), corn oil (Zea mays), tobacco oil (Nicotiana
sp. such as Nicotana tabacum or Nicotiana benthamiana), peanut oil
(Arachis hypogaea), palm oil (Elaeis guineensis), cottonseed oil
(Gossypium hirsutumn), coconut oil (Cocos nucifera), avocado oil
(Persea americana), olive oil (Olea europaea), cashew oil
(Anacardium occidentale), macadamia oil (Macadamia intergrifolia),
almond oil (Prunus amygdalus), oat seed oil (Avena sativa), rice
oil (Oryza sp. such as Oryza sativa and Oryza glaberrima),
Arabidopsis seed oil (Arabidopsis thaliana), or oil from the seed
of Acrocomia aculeata (macauba palm), Aracinis hypogaea (peanut),
Astrocaryum murumuru (murumuru), Astrocaryum vulgare (tucumh),
Attalea geraensis (Indaia-rateiro), Attalea humilis (American oil
palm), Attalea oleifera (andaia), Attalea phalerata (uricuri),
Atalea speciosa (babassu), Beta vulgaris (sugar beet), Camelina
sativa (false flax), Caryocar brasiliense (pequi), Crambe
abyssinica (Abyssinian kale), Cucumis melo (melon), Hordeum vulgare
(barley), Jatropha curcas (physic nut), Joannesia princeps (arara
nut-tree), Licania rigida (oiticica), Lupinus anguslifolius
(lupin), Mauritia flexuosa (buriti palm), Maximiliana maripa (inaja
palm), Miscanthus sp. such as Miscanthus x giganteus and Miscanthus
sinensis, Oenocarpus bacaba (bacaba-do-azeite), Oenocarpus bataua
(pataua), Oenocarpus distichus (bacaba-de-leque), Panicum virgatum
(switchgrass), Paraqueiba paraensis (mari), Persea amencana
(avocado), Pongamia pinnata (Indian beech), Populus trichocarpa,
Ricinus communis (castor), Saccharum sp. (sugarcane), Sesamum
indicum (sesame), Solanum tuberosum (potato), Sorghum sp. such as
Sorghum bicolor, Sorghum vulgare, Theobroma grandiforum (cupuassu),
Trifolium sp., Trithrinax brasiliensis (Brazilian needle pahn) and
Triticum sp. (wheat) such as Truticum aestivum. Seedoil may be
extracted from seed/grain by any method known in the art. This
typically involves extraction with nonpolar solvents such as
diethyl ether, petroleum ether, chloroform/methanol or butanol
mixtures, generally associated with first crushing of the seeds.
Lipids associated with the starch in the grain may be extracted
with water-saturated butanol. The seedoil may be "de-gummed" by
methods known in the art to remove polysaccharides or treated in
other ways to remove contaminants or improve purity, stability, or
colour. The TAGs and other esters in the seedoil may be hydrolysed
to release free fatty acids, or the seedoil hydrogenated, treated
chemically, or enzymatically as known in the art.
[0998] As used herein, the term "fatty acid" refers to a carboxylic
acid with a long aliphatic tail of at least 8 carbon atoms in
length, either saturated or unsaturated. Typically, fatty acids
have a carbon-carbon bonded chain of at least 12 carbons in length.
Most naturally occurring fatty acids have an even number of carbon
atoms because their biosynthesis involves acetate which has two
carbon atoms. The fatty acids may be in a free state
(non-esterified) or in an esterified form such as part of a TAG,
DAG, MAG, acyl-CoA (thio-ester) bound, or other covalently bound
form. When covalently bound in an esterified form, the fatty acid
is referred to herein as an "acyl" group. The fatty acid may be
esterified as a phospholipid such as a phosphatidylcholine (PC),
phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol,
phosphatidylinositol, or diphosphatidylglycerol. Saturated fatty
acids do not contain any double bonds or other functional groups
along the chain. The term "saturated" refers to hydrogen, in that
all carbons (apart from the carboxylic acid [--COOH] group) contain
as many hydrogens as possible. In other words, the omega (.omega.)
end contains 3 hydrogens (CH3-) and each carbon within the chain
contains 2 hydrogens (--CH2-). Unsaturated fatty acids are of
similar form to saturated fatty acids, except that one or more
alkene functional groups exist along the chain, with each alkene
substituting a singly-bonded "--CH2-CH2-" part of the chain with a
doubly-bonded "--CH.dbd.CH--" portion (that is, a carbon double
bonded to another carbon). The two next carbon atoms in the chain
that are bound to either side of the double bond can occur in a cis
or trans configuration.
[0999] As used herein, the terms "polyunsaturated fatty acid" or
"PUFA" refer to a fatty acid which comprises at least 12 carbon
atoms in its carbon chain and at least two alkene groups
(carbon-carbon double bonds). The PUFA content of the vegetative
plant part, or the non-human organism or part thereof of the
invention may be increased or decreased depending on the
combination of exogenous polynucleotides expressed in the
vegetative plant part, or non-human organism or part thereof, or
seed of the invention. For example, when an MGAT is expressed the
PUFA level typically increases, whereas when DGAT1 is expressed
alone or in combination with WRI1, the PUFA level is typically
decreased due to an increase in the level of oleic acid.
Furthermore, if .DELTA.12 desaturase activity is reduced, for
example by silencing an endogenous .DELTA.12 desaturase, PUFA
content is unlikely to increase in the absence of an exogenous
polynucleotide encoding a different .DELTA.12 desaturase.
[1000] "Monoacylglyceride" or "MAG" is glyceride in which the
glycerol is esterified with one fatty acid. As used herein, MAG
comprises a hydroxyl group at an sn-1/3 (also referred to herein as
sn-1 MAG or 1-MAG or 1/3-MAG) or sn-2 position (also referred to
herein as 2-MAG), and therefore MAG does not include phosphorylated
molecules such as PA or PC. MAG is thus a component of neutral
lipids in a cell.
[1001] "Diacylglyceride" or "DAG" is glyceride in which the
glycerol is esterified with two fatty acids which may be the same
or, preferably, different. As used herein, DAG comprises a hydroxyl
group at a sn-1,3 or sn-2 position, and therefore DAG does not
include phosphorylated molecules such as PA or PC. DAG is thus a
component of neutral lipids in a cell. In the Kennedy pathway of
DAG synthesis (FIG. 1), the precursor sn-glycerol-3-phosphate
(G-3-P) is esterified to two acyl groups, each coming from a fatty
acid coenzyme A ester, in a first reaction catalysed by a
glycerol-3-phosphate acyltransferase (GPAT) at position sn-1 to
form LysoPA, followed by a second acylation at position sn-2
catalysed by a lysophosphatidic acid acyltransferase (LPAAT) to
form phosphatidic acid (PA). This intermediate is then
de-phosphorylated to form DAG. In an alternative anabolic pathway
(FIG. 1), DAG may be formed by the acylation of either sn-1 MAG or
preferably sn-2 MAG, catalysed by MGAT. DAG may also be formed from
TAG by removal of an acyl group by a lipase, or from PC essentially
by removal of a choline headgroup by any of the enzymes CPT, PDCT
or PLC (FIG. 1).
[1002] "Triacylglyceride" or "TAG" is glyceride in which the
glycerol is esterified with three fatty acids which may be the same
(e.g. as in tri-olein) or, more commonly, different. In the Kennedy
pathway of TAG synthesis, DAG is formed as described above, and
then a third acyl group is esterified to the glycerol backbone by
the activity of DGAT. Alternative pathways for formation of TAG
include one catalysed by the enzyme PDAT and the MGAT pathway
described herein.
[1003] As used herein, the term "acyltransferase" refers to a
protein which is capable of transferring an acyl group from
acyl-CoA onto a substrate and includes MGATs, GPATs and DGATs.
[1004] As used herein, the term "Wrinkled 1" or "WRI1" or "WRL1"
refers to a transcription factor of the AP2/ERWEBP class which
regulates the expression of several enzymes involved in glycolysis
and de novo fatty acid biosynthesis. WRI1 has two plant-specific
(AP2/EREB) DNA-binding domains. WRI1 in at least Arabidopsis also
regulates the breakdown of sucrose via glycolysis thereby
regulating the supply of precursors for fatty acid biosynthesis. In
other words, it controls the carbon flow from the photosynthate to
storage lipids. wri1 mutants have wrinkled seed phenotype, due to a
defect in the incorporation of sucrose and glucose into TAGs.
[1005] Examples of genes which are trancribed by WRI1 include, but
are not limited to, one or more, preferably all, of pyruvate kinase
(At5g52920, At3g22960), pyruvate dehydrogenase (PDH) Elalpha
subunit (At1g01090), acetyl-CoA carboxylase (ACCase), BCCP2 subunit
(At5g15530), enoyl-ACP reductase (At2g05990; EAR), phosphoglycerate
mutase (At1g22170), cytosolic fluctokinase, and cytosolic
phosphoglycerate mutase, sucrose synthase (SuSy) (see, for example,
Liu et al., 2010b; Baud et al., 2007; Ruuska et al., 2002).
[1006] WRL1 contains the conserved domain AP2 (cd00018). AP2 is a
DNA-binding domain found in transcription regulators in plants such
as APETALA2 and EREBP (ethylene responsive element binding
protein). In EREBPs the domain specifically binds to the 11 bp GCC
box of the ethylene response element (ERE), a promotor element
essential for ethylene responsiveness. EREBPs and the C-repeat
binding factor CBFI, which is involved in stress response, contain
a single copy of the AP2 domain. APETALA2-like proteins, which play
a role in plant development contain two copies.
[1007] Other sequence motifs in WRI1 and its functional homologs
include:
TABLE-US-00001 1. (SEQ ID NO: 356) R G V T/S R H R W T G R. 2. (SEQ
ID NO: 357) F/Y E A H L W D K. 3. (SEQ ID NO: 358) D L A A L K Y W
G. 4. (SEQ ID NO: 359) S X G F S/A R G X. 5. (SEQ ID NO: 360) H H
H/Q N G R/K W E A R I G R/K V. 6. (SEQ ID NO: 361) Q E E A A A X Y
D.
[1008] As used herein, the term "Wrinkled 1" or "WRI1" also
includes "Wrinkled 1-like" or "WRI1-like" proteins. Examples of
WRI1 proteins include Accession Nos: Q6X5Y6, (Arabidopsis thaliana;
SEQ ID NO:280), XP_002876251.1 (Arabidopsis lyrata subsp. Lyrata;
SEQ ID NO:281), ABD16282.1 (Brassica napus; SEQ ID NO:282),
AD016346.1 (Brassica napus; SEQ ID NO:283), XP_003530370.1 (Glycine
max; SEQ ID NO:284), AEO22131.1 (Jatropha curcas; SEQ ID NO:285),
XP_002525305.1 (Ricinus communis; SEQ ID NO:286), XP_002316459.1
(Populus trichocarpa; SEQ ID NO:287), CBI29147.3 (Vitis vinifera;
SEQ ID NO:288), XP_003578997.1 (Brachypodium distachyon; SEQ ID
NO:289), BAJ86627.1 (Hordeum vulgare subsp. vulgare; SEQ ID
NO:290), EAY79792.1 (Oryza saliva; SEQ ID NO:291), XP_002450194.1
(Sorghum bicolor; SEQ ID NO:292), ACG32367.1 (Zea mays; SEQ ID
NO:293), XP_003561189.1 (Brachypodium dislachyon; SEQ ID NO:294),
ABL85061.1 (Brachypodium sylvaticum; SEQ ID NO:295), BAD68417.1
(Oryza saliva; SEQ ID NO:296), XP_002437819.1 (Sorghum bicolor, SEQ
ID NO:297), XP_002441444.1 (Sorghum bicolor; SEQ ID NO:298),
XP_003530686.1 (Glycine max; SEQ ID NO:299), XP_003553203.1
(Glycine max; SEQ ID NO:300), XP_002315794.1 (Populus trichocarpa;
SEQ ID NO:301), XP_002270149.1 (Vitis vinifera; SEQ ID NO:302),
XP_003533548.1 (Glycine max; SEQ ID NO:303), XP_003551723.1
(Glycine mar; SEQ ID NO:304), XP_003621117.1 (Medicago truncatula;
SEQ ID NO:305), XP_002323836.1 (Populus trichocarpa; SEQ ID
NO:306), XP_002517474.1 (Ricinus communis; SEQ ID NO:307),
CAN79925.1 (Vitis vinifera; SEQ ID NO:308), XP_003572236.1
(Brachypodium distachyon; SEQ ID NO:309), BAD10030.1 (Oryza saliva;
SEQ ID NO:310), XP_002444429.1 (Sorghum bicolor; SEQ ID NO:311),
NP_001170359.1 (Zea mays; SEQ ID NO:312), XP_002889265.1
(Arabidopsis lyrata subsp. lyrata; SEQ ID NO:313), AAF68121.1
(Arabidopsis thaliana; SEQ ID NO:314), NP_178088.2 (Arabidopsis
thaliana; SEQ ID NO:315), XP_002890145.1 (Arabidopsis lyrata subsp.
lyrata; SEQ ID NO:316), BAJ33872.1 (Thellungiella halophila; SEQ ID
NO:317), NP_563990.1 (Arabidopsis thaliana; SEQ ID NO:318),
XP_003530350.1 (Glycine max; SEQ ID NO:319), XP_003578142.1
(Brachypodium distachyon; SEQ ID NO:320), EAZ09147.1 (Oryza saliva;
SEQ ID NO:321), XP_002460236.1 (Sorghum bicolor; SEQ ID NO:322),
NP_001146338.1 (Zea mays; SEQ ID NO:323), XP_003519167.1 (Glycine
mar; SEQ ID NO:324), XP_003550676.1 (Glycine max, SEQ ID NO:325),
XP_003610261.1 (Medicago truncatula; SEQ ID NO:326), XP_003524030.1
(Glycine max; SEQ ID NO:327), XP_003525949.1 (Glycine max; SEQ ID
NO:328), XP_002325111.1 (Populus trichocarpa; SEQ ID NO:329),
CBI36586.3 (Vitis vinifera; SEQ ID NO:330), XP_002273046.2 (Vitis
vinifera; SEQ ID NO:331), XP_002303866.1 (Populus trichocarpa; SEQ
ID NO:332), and CBI25261.3 (Vitis vinifera; SEQ ID NO:333). Further
examples include Sorbi-WRL1 (SEQ ID NO:334), Lupan-WRL1 (SEQ ID
NO:335), Ricco-WRL1 (SEQ ID NO:336), and Lupin angustifolius WRI1
(SEQ ID NO:337).
[1009] As used herein, the term "monoacylglycerol acyltransferase"
or "MGAT" refers to a protein which transfers a fatty acyl group
from acyl-CoA to a MAG substrate to produce DAG. Thus, the term
"monoacylglycerol acyltransferase activity" at least refers to the
transfer of an acyl group from acyl-CoA to MAG to produce DAG. MGAT
is best known for its role in fat absorption in the intestine of
mammals, where the fatty acids and sn-2 MAG generated from the
digestion of dietary fat are resynthesized into TAG in enterocytes
for chylomicron synthesis and secretion. MGAT catalyzes the first
step of this process, in which the acyl group from fatty acyl-CoA,
formed from fatty acids and CoA, and sn-2 MAG are covalently
joined. The term "MGAT" as used herein includes enzymes that act on
sn-1/3 MAG and/or sn-2 MAG substrates to form sn-1,3 DAG and/or
sn-1,2/2,3-DAG, respectively. In a preferred embodiment, the MGAT
has a preference for sn-2 MAG substrate relative to sn-1 MAG, or
substantially uses only sn-2 MAG as substrate (examples include
MGATs described in Cao et al., 2003 (specificity of mouse MGAT1 for
sn2-18:1-MAG>sn1/3-18:1-MAG (FIG. 5)); Yen and Farese, 2003
(general activities of mouse MGAT1 and human MGAT2 are higher on
2-MAG than on 1-MAG acyl-acceptor substrates (FIG. 5); and Cheng et
al., 2003 (activity of human MGAT3 on 2-MAGs is much higher than on
1/3-MAG substrates (FIG. 2D)).
[1010] As used herein, MGAT does not include enzymes which transfer
an acyl group preferentially to LysoPA relative to MAG, such
enzymes are known as LPAATs. That is, a MGAT preferentially uses
non-phosphorylated monoacyl substrates, even though they may have
low catalytic activity on LysoPA. A preferred MGAT does not have
detectable activity in acylating LysoPA. As shown herein, a MGAT
(i.e., M. musculus MGAT2) may also have DGAT function but
predominantly functions as a MGAT, i.e., it has greater catalytic
activity as a MGAT than as a DGAT when the enzyme activity is
expressed in units of nmoles product/min/mg protein (also see Yen
et al., 2002).
[1011] There are three known classes of MGAT, referred to as,
MGAT1, MGAT2 and MGAT3, respectively. Homologs of the human MGAT1
gene (AF384163; SEQ ID NO:7) are present (i.e. sequences are known)
at least in chimpanzee, dog, cow, mouse, rat, zebrafish,
Caenorhabditis elegans, Schizosaccharomyces pombe, Saccharomyces
cerevisiae, Kluyveromyces lactis, Eremothecium gossypii,
Magnaporthe grisea, and Neurospora crassa. Homologs of the human
MGAT2 gene (AY157608) are present at least in chimpanzee, dog, cow,
mouse, rat, chicken, zebrafish, fruit fly, and mosquito. Homologs
of the human MGAT3 gene (AY229854) are present at least in
chimpanzee, dog, cow, and zebrafish. However, homologs from other
organisms can be readily identified by methods known in the art for
identifying homologous sequences.
[1012] Examples of MGAT1 polypeptides include proteins encoded by
MGAT1 genes from Homo sapiens (AF384163; SEQ ID NO:7), Mus musculus
(AF384162; SEQ ID NO:8), Pan troglodytes (XM_001166055 and
XM_0526044.2; SEQ ID NO:9 and SEQ ID NO:10, respectively), Canis
familiaris (XM_545667.2; SEQ ID NO:11), Bos taurus (NM_001001153.2;
SEQ ID NO:12), Rattus norvegicus (NM_001108803.1; SEQ ID NO:13),
Danio rerio MGAT1 (NM_001122623.1; SEQ ID NO:14), Caenorhabditis
elegans (NM_073012.4, NM_182380.5, NM_065258.3, NM_075068.3, and
NM_072248.3; SEQ ID NO:15, SEQ ID NO:16, SEQ ID NO:17, SEQ ID
NO:18, and SEQ ID NO:19, respectively), Kluyveromyces lactis
(XM_455588.1; SEQ ID NO:20), Ashbya gossypii (NM_208895.1; SEQ ID
NO:21), Magnaporthe oryzae (XM_368741.1; SEQ ID NO:22), Ciona
intestinalis predicted (XM_002120843.1 SEQ ID NO:23). Examples of
MGAT2 polypeptides include proteins encoded by MGAT2 genes from
Homo sapiens (AY157608; SEQ ID NO:24), Mus musculus (AY157609; SEQ
ID NO:25), Pan troglodytes (XM_522112.2; SEQ ID NO:26), Canis
familiaris (XM_542304.1; SEQ ID NO:27), Bos taurus (NM_001099136.1;
SEQ ID NO:28), Rattus norvegicus (NM_001109436.2; SEQ ID NO:29),
Gallus gallus (XM_424082.2; SEQ ID NO:30), Danio rerio
(NM_001006083.1 SEQ ID NO:31), Drosophila melanogaster
(NM_136474.2, NM_136473.2, and NM_136475.2; SEQ ID NO:32, SEQ ID
NO:33, and SEQ ID NO:34, resepectively), Anopheles gambiae
(XM_001688709.1 and XM_315985; SEQ ID NO:35 and SEQ ID NO:36,
respectively), Tribolium castaneum (XM_970053.1; SEQ ID NO:37).
Examples of MGAT3 polypeptides include proteins encoded by MGAT3
genes from Homo sapiens (AY229854; SEQ ID NO:38), Pan troglodytes
(XM_001154107.1, XM_001154171.1, and XM_527842.2; SEQ ID NO:39, SEQ
ID NO:40, and SEQ ID NO:41), Canis familiaris (XM_845212.1; SEQ ID
NO:42), Bos taurus (XM_870406.4; SEQ ID NO:43), Danio rerio
(XM_688413.4; SEQ ID NO:44).
[1013] As used herein "MGAT pathway" refers to an anabolic pathway,
different to the Kennedy pathway for the formation of TAG, in which
DAG is formed by the acylation of either sn-1 MAG or preferably
sn-2 MAG, catalysed by MGAT. The DAG may subsequently be used to
form TAG or other lipids. The MGAT pathway is exemplified in FIG.
1.
[1014] As used herein, the term "diacylglycerol acyltransferase"
(DGAT) refers to a protein which transfers a fatty acyl group from
acyl-CoA to a DAG substrate to produce TAG. Thus, the term
"diacylglycerol acyltransferase activity" refers to the transfer of
an acyl group from acyl-CoA to DAG to produce TAG. A DGAT may also
have MGAT function but predominantly functions as a DGAT, i.e., it
has greater catalytic activity as a DGAT than as a MGAT when the
enzyme activity is expressed in units of nmoles product/min/mg
protein (see for example, Yen et al., 2005).
[1015] There are three known types of DGAT, referred to as DGAT1,
DGAT2 and DGAT3, respectively. DGAT1 polypeptides typically have 10
transmembrane domains, DGAT2 polypeptides typically have 2
transmembrane domains, whilst DGAT3 polypeptides typically have
none and are thought to be soluble in the cytoplasm, not integrated
into membranes. Examples of DGAT1 polypeptides include proteins
encoded by DGAT1 genes from Aspergillus fumigatus (XP_755172.1; SEQ
ID NO:347), Arabidopsis thaliana (CAB44774.1; SEQ ID NO:83),
Ricinus communis (AAR11479.1; SEQ ID NO:348), Vernicia fordii
(ABC94472.1; SEQ ID NO:349), Vernonia galamensis (ABV21945.1 and
ABV21946.1; SEQ ID NO:350 and SEQ ID NO:351, respectively),
Euonymus alatus (AAV31083.1; SEQ ID NO:352), Caenorhabditis elegans
(AAF82410.1; SEQ ID NO:353), Rattus norvegicus (NP_445889.1; SEQ ID
NO:354), Homo sapiens (NP_036211.2; SEQ ID NO:355), as well as
variants and/or mutants thereof. Examples of DGAT2 polypeptides
include proteins encoded by DGAT2 genes from Arabidopsis thaliana
(NP_566952.1; SEQ ID NO:212), Ricinus communis (AAY16324.1; SEQ ID
NO:213), Vernicia fordii (ABC94474.1; SEQ ID NO:214), Mortierella
ramanniana (AAK84179.1; SEQ ID NO:215), Homo sapiens (Q96PD7.2; SEQ
ID NO:216) (Q58HT5.1; SEQ ID NO:217), Bos taurus (Q70VZ8.1; SEQ ID
NO:218), Mus musculus (AAK84175.1; SEQ ID NO:219), as well as
variants and/or mutants thereof.
[1016] Examples of DGAT3 polypeptides include proteins encoded by
DGAT3 genes from peanut (Arachis hypogaea, Saha, et al., 2006), as
well as variants and/or mutants thereof. A DGAT has little or no
detectable MGAT activity, for example, less than 300 pmol/min/mg
protein, preferably less than 200 pmol/min/mg protein, more
preferably less than 100 pmol/min/mg protein.
[1017] DGAT2 but not DGAT1 shares high sequence homology with the
MGAT enzymes, suggesting that DGAT2 and MGAT genes likely share a
common genetic origin. Although multiple isoforms are involved in
catalysing the same step in TAG synthesis, they may play distinct
functional roles, as suggested by differential tissue distribution
and subcellular localization of the DGAT/MGAT family of enzymes. In
mammals, MGAT1 is mainly expressed in stomach, kidney, adipose
tissue, whilst MGAT2 and MGAT3 show highest expression in the small
intestine. In mammals, DGAT1 is ubiquitously expressed in many
tissues, with highest expression in small intestine, whilst DGAT2
is most abundant in liver. MGAT3 only exists in higher mammals and
humans, but not in rodents from bioinformatic analysis. MGAT3
shares higher sequence homology to DGAT2 than MGAT1 and MGAT3.
MGAT3 exhibits significantly higher DGAT activity than MGAT1 and
MGAT2 enzymes (MGAT3>MGAT1>MGAT2) when either MAGs or DAGs
were used as substrates, suggesting MGAT3 functions as a putative
TAG synthase.
[1018] Both MGAT1 and MGAT2 belong to the same class of
acyltransferases as DGAT2. Some of the motifs that have been shown
to be important for DGAT2 catalytic activity in some DGAT2s are
also conserved in MGAT acyltransferases. Of particular interest is
a putative neutral lipid-binding domain with the concensus sequence
FLXLXXXN (SEQ ID NO:224) where each X is independently any amino
acid other than proline, and N is any nonpolar amino acid, located
within the N-terminal transmembrane region followed by a putative
glycerol/phospholipid acyltransferase domain. The FLXLXXXN motif
(SEQ ID NO:224) is found in the mouse DGAT2 (amino acids 81-88) and
MGAT1/2 but not in yeast or plant DGAT2s. It is important for
activity of the mouse DGAT2. Other DGAT2 and/or MGAT1/2 sequence
motifs include:
1. A highly conserved YFP tripeptide (SEQ ID NO:220) in most DGAT2
polypeptides and also in MGAT1 and MGAT2, for example, present as
amino acids 139-141 in mouse DGAT2. Mutating this motif within the
yeast DGAT2 with non-conservative substitutions rendered the enzyme
non-functional. 2. HPHG tetrapeptide (SEQ ID NO:221), highly
conserved in MGATs as well as in DGAT2 sequences from animals and
fungi, for example, present as amino acids 161-164 in mouse DGAT2,
and important for catalytic activity at least in yeast and mouse
DGAT2. Plant DGAT2 acyltransferases have a EPHS (SEQ ID NO:222)
conserved sequence instead, so conservative changes to the first
and fourth amino acids can be tolerated. 3. A longer conserved
motif which is part of the putative glycerol phospholipid domain.
An example of this motif is RXGFX(K/R)XAXXXGXXX(L/V)VPXXXFG(E/Q)
(SEQ ID NO:223), which is present as amino acids 304-327 in mouse
DGAT2. This motif is less conserved in amino acid sequence than the
others, as would be expected from its length, but homologs can be
recognised by motif searching. The spacing may vary between the
more conserved amino acids, i.e., there may be additional X amino
acids within the motif, or less X amino acids compared to the
sequence above.
[1019] As used herein, the term "glycerol-3-phosphate
acyltransferase" or "GPAT" refers to a protein which acylates
glycerol-3-phosphate (G-3-P) to form LysoPA and/or MAG, the latter
product forming if the GPAT also has phosphatase activity on
LysoPA. The acyl group that is transferred is typically from
acyl-CoA. Thus, the term "glycerol-3-phosphate acyltransferase
activity" refers to the acylation of G-3-P to form LysoPA and/or
MAG. The term "GPAT" encompasses enzymes that acylate G-3-P to form
sn-1 LPA and/or sn-2 LPA, preferably sn-2 LPA. In a preferred
embodiment, the GPAT has phosphatase activity. In a most preferred
embodiment, the GPAT is a sn-2 GPAT having phosphatase activity
which produces sn-2 MAG.
[1020] As used herein, the term "sn-1 glycerol-3-phosphate
acyltransferase" (sn-1 GPAT) refers to a protein which acylates
sn-glycerol-3-phosphate (G-3-P) to preferentially form
1-acyl-sn-glycerol-3-phosphate (sn-1 LPA). Thus, the term "sn-1
glycerol-3-phosphate acyltransferase activity" refers to the
acylation of sn-glycerol-3-phosphate to form
1-acyl-sn-glycerol-3-phosphate (sn-1 LPA).
[1021] As used herein, the term "sn-2 glycerol-3-phosphate
acyltransferase" (sn-2 GPAT) refers to a protein which acylates
sn-glycerol-3-phosphate (G-3-P) to preferentially form
2-acyl-sn-glycerol-3-phosphate (sn-2 LPA). Thus, the term "sn-2
glycerol-3-phosphate acyltransferase activity" refers to the
acylation of sn-glycerol-3-phosphate to form
2-acyl-sn-glycerol-3-phosphate (sn-2 LPA).
[1022] The GPAT family is large and all known members contain two
conserved domains, a plsC acyltransferase domain (PF01553; SEQ ID
NO:225) and a HAD-like hydrolase (PF12710; SEQ ID NO:226)
superfamily domain. In addition to this, in Arabidopsis thaliana,
GPAT4-8 all contain a N-terminal region homologous to a
phosphoserine phosphatase domain (PF00702; SEQ ID NO:227). GPAT4
and GPAT6 both contain conserved residues that are known to be
critical to phosphatase activity, specifically conserved amino
acids (shown in bold) in Motif I (DXDX[TN/V][L/V]; SEQ ID NO:229)
and Motif III (K-[G/S][D/S]XXX[D/N]; SEQ ID NO:330) located at the
N-terminus (Yang et al., 2010). Preferably, the GPAT has sn-2
preference and phosphatase activity to produce sn-2 MAG (also
referred to herein as "2-MAG") from glycerol-3-phosphate (G-3-P)
(FIG. 1), for example, GPAT4 (NP_171667.1; SEQ ID NO:144) and GPAT6
(NP_181346.1; SEQ ID NO:145) from Arabidopsis. More preferably, the
GPAT uses acyl-CoA as a fatty acid substrate.
[1023] Homologues of GPAT4 (NP_171667.1; SEQ ID NO:144) and GPAT6
(NP_181346.1; SEQ ID NO:145) include AAF02784.1 (Arabidopsis
thaliana; SEQ ID NO:146), AAL32544.1 (Arabidopsis thaliana; SEQ ID
NO:147), AAP03413.1 (Oryza saliva; SEQ ID NO:148), ABK25381.1
(Picea sitchensis; SEQ ID NO:149), ACN34546.1 (Zea Mays; SEQ ID
NO:150), BAF00762.1 (Arabidopsis thaliana; SEQ ID NO:151),
BAH00933.1 (Oryza saliva; SEQ ID NO:152), EAY84189.1 (Oryza saliva;
SEQ ID NO:153), EAY98245.1 (Oryza saliva; SEQ ID NO:154),
EAZ21484.1 (Oryza saliva; SEQ ID NO:155), EEC71826.1 (Oryza saliva;
SEQ ID NO:156), EEC76137.1 (Oryza sativa; SEQ ID NO:157),
EEE59882.1 (Oryza saliva; SEQ ID NO:158), EFJ08963.1 (Selaginella
moellendorfii; SEQ ID NO:159), EFJ08964.1 (Selaginella
moellendorfii; SEQ ID NO:160), EFJ11200.1 (Selaginella
moellendorfii; SEQ ID NO:161), EFJ15664.1 (Selaginella
moellendorfii; SEQ ID NO:162), EFJ24086.1 (Selaginella
moellendorfii; SEQ ID NO:163), EFJ29816.1 (Selaginella
moellendorfii; SEQ ID NO:164), EFJ29817.1 (Selaginella
moellendorfii; SEQ ID NO:165), NP_001044839.1 (Oryza saliva; SEQ ID
NO:166), NP_001045668.1 (Oryza saliva; SEQ ID NO:167),
NP_001147442.1 (Zea mays; SEQ ID NO:168), NP_001149307.1 (Zea mays;
SEQ ID NO:169), NP_001168351.1 (Zea mays; SEQ ID NO:170),
AFH02724.1 (Brassica napus; SEQ ID NO:171) NP_191950.2 (Arabidopsis
thaliana; SEQ ID NO:172), XP_001765001.1 (Physcomitrella patens;
SEQ ID NO:173), XP_001769671.1 (Physcomitrella patens; SEQ ID
NO:174), XP_001769724.1 (Physcomitrella patens; SEQ ID NO:175),
XP_001771186.1 (Physcomitrella patens; SEQ ID NO:176),
XP_001780533.1 (Physcomitrella patens; SEQ ID NO:177),
XP_002268513.1 (Vitis vinifera; SEQ ID NO:178), XP_002275348.1
(Vitis vinifera; SEQ ID NO:179), XP_002276032.1 (Vitis vinifera;
SEQ ID NO:180), XP_002279091.1 (Vitis vinifera; SEQ ID NO:181),
XP_002309124.1 (Populus trichocarpa; SEQ ID NO:182), XP_002309276.1
(Populus richocarpa; SEQ ID NO:183), XP_002322752.1 (Populus
trichocarpa; SEQ ID NO:184), XP_002323563.1 (Populus trichocarpa;
SEQ ID NO:185), XP_002439887.1 (Sorghum bicolor, SEQ ID NO:186),
XP_002458786.1 (Sorghum bicolor; SEQ ID NO:187), XP_002463916.1
(Sorghum bicolor, SEQ ID NO:188), XP_002464630.1 (Sorghum bicolor,
SEQ ID NO:189), XP_002511873.1 (Ricinus communis; SEQ ID NO:190),
XP_002517438.1 (Ricinus communis; SEQ ID NO:191), XP_002520171.1
(Ricinus communis; SEQ ID NO:192), XP_002872955.1 (Arabidopsis
lyrata; SEQ ID NO:193), XP_002881564.1 (Arabidopsis lyrata; SEQ ID
NO:194), ACT32032.1 (Vernicia fordii; SEQ ID NO:195),
NP_001051189.1 (Oryza saliva; SEQ ID NO:196), AFH02725.1 (Brassica
napus; SEQ ID NO:197), XP_002320138.1 (Populus trichocarpa; SEQ ID
NO:198), XP_002451377.1 (Sorghum bicolor; SEQ ID NO:199),
XP_002531350.1 (Ricinus communis; SEQ ID NO:200), and
XP_002889361.1 (Arabidopsis lyrata; SEQ ID NO:201).
[1024] Conserved motifs and/or residues can be used as a
sequence-based diagnostic for the identification of bifunctional
GPAT/phosphatase enzymes. Alternatively, a more stringent
function-based assay could be utilised. Such an assay involves, for
example, feeding labelled glycerol-3-phosphate to cells or
microsomes and quantifying the levels of labelled products by
thin-layer chromatography or a similar technique. GPAT activity
results in the production of labelled LPA whilst GPAT/phosphatase
activity results in the production of labelled MAG.
[1025] As used herein, the term "Oleosin" refers to an amphipathic
protein present in the membrane of oil bodies in the storage
tissues of seeds (see, for example, Huang, 1996; Lin et al., 2005;
Capuano et al., 2007; Lui et al., 2009; Shimada and Hara-Nishimura,
2010).
[1026] Plant seeds accumulate TAG in subcellular structures called
oil bodies. These organelles consist of a TAG core surround by a
phospholipid monolayer containing several embedded proteins
including oleosins (Jolivet et al., 2004). Oleosins represent the
most abundant protein in the membrane of oil bodies.
[1027] Oleosins are of low M.sub.r (15-26,000). Within each seed
species, there are usually two or more oleosins of different
M.sub.r. Each oleosin molecule contains a relatively hydrophilic
N-terminal domain (for example, about 48 amino acid residues), a
central totally hydrophobic domain (for example, of about 70-80
amino acid residues) which is particularly rich in aliphatic amino
acids such as alanine, glycine, leucine, isoleucine and valine, and
an amphipathic .alpha.-helical domain (for example, about of about
33 amino acid residues) at or near the C-terminus. Generally, the
central stretch of hydrophobic residues is inserted into the lipid
core and the amphiphatic N-terminal and/or amphiphatic C-terminal
are located at the surface of the oil bodies, with positively
charged residues embedded in a phospholipid monolayer and the
negatively charged ones exposed to the exterior.
[1028] As used herein, the term "Oleosin" encompasses polyoleosins
which have multiple oleosin polypeptides fused together as a single
polypeptide, for example 2.times., 4.times. or 6.times. oleosin
peptides, and caleosins which bind calcium (Froissard et al.,
2009), and steroleosins which bind sterols. However, generally a
large proportion of the oleosins of oil bodies will not be
caleosins and/or steroleosins.
[1029] A substantial number of oleosin protein sequences, and
nucleotide sequences encoding therefor, are known from a large
number of different plant species. Examples include, but are not
limited to, oleosins from Arabidposis, canola, corn, rice, peanut,
castor, soybean, flax, grape, cabbage, cotton, sunflower, sorghum
and barley. Examples of oleosins (with their Accession Nos) include
Brassica napus oleosin (CAA57545.1; SEQ ID NO:362), Brassica napus
oleosin S1-1 (ACG69504.1; SEQ ID NO:363), Brassica napus oleosin
S2-1 (ACG69503.1; SEQ ID NO:364), Brassica napus oleosin S3-1
(ACG69513.1; SEQ ID NO:365), Brassica napus oleosin S4-1
(ACG69507.1; SEQ ID NO:366), Brassica napus oleosin S5-1
(ACG69511.1; SEQ ID NO:367), Arachis hypogaea oleosin 1
(AAZ20276.1; SEQ ID NO:368), Arachis hypogaea oleosin 2
(AAU21500.1; SEQ ID NO:369), Arachis hypogaea oleosin 3
(AAU21501.1; SEQ ID NO:370), Arachis hypogaea oleosin 5
(ABC96763.1; SEQ ID NO:371), Ricinus communis oleosin 1
(EEF40948.1; SEQ ID NO:372), Ricinus communis oleosin 2
(EEF51616.1; SEQ ID NO:373), Glycine mar oleosin isoform a
(P29530.2; SEQ ID NO:374), Glycine max oleosin isoform b (P29531.1;
SEQ ID NO:375), Linum usilatissimum oleosin low molecular weight
isoform (ABB01622.1; SEQ ID NO:376), Linum usitatissimum oleosin
high molecular weight isoform (ABB01624.1; SEQ ID NO:377),
Helianthus annuus oleosin (CAA44224.1; SEQ ID NO:378), Zea mays
oleosin (NP_001105338.1; SEQ ID NO:379), Brassica napus steroleosin
(ABM30178.1; SEQ ID NO:380), Brassica napus steroleosin SLO1-1
(ACG69522.1; SEQ ID NO:381), Brassica napus steroleosin SLO2-1
(ACG69525.1; SEQ ID NO:382), Sesamum indicum steroleosin
(AAL13315.1; SEQ ID NO:383), Zea mays steroleosin (NP_001152614.1;
SEQ ID NO:384), Brassica napus caleosin CLO-1 (ACG69529.1; SEQ ID
NO:385), Brassica napus caleosin CLO-3 (ACG69527.1; SEQ ID NO:386),
Sesamum indicum caleosin (AAF13743.1; SEQ ID NO:387), Zea mays
caleosin (NP_001151906.1; SEQ ID NO:388).
[1030] As used herein, the term a "polypeptide involved in starch
biosynthesis" refers to any polypeptide, the downregulation of
which in a cell below normal (wild-type) levels results in a
reduction in the level of starch synthesis and an increase in the
levels of starch. An example of such a polypeptide is AGPase.
[1031] As used herein, the term "ADP-glucose phosphorylase" or
"AGPase" refers to an enzyme which regulates starch biosynthesis,
catalysing conversion of glucose-1-phosphate and ATP to ADP-glucose
which serves as the building block for starch polymers. The active
form of the AGPase enzyme consists of 2 large and 2 small
subunits.
[1032] The ADPase enzyme in plants exists primarily as a tetramer
which consists of 2 large and 2 small subunits. Although these
subunits differ in their catalytic and regulatory roles depending
on the species (Kuhn et al., 2009), in plants the small subunit
generally displays catalytic activity. The molecular weight of the
small subunit is approximately 50-55 kDa. The molecular weight of
the large large subunit is approximately 55-60 kDa. The plant
enzyme is strongly activated by 3-phosphoglycerate (PGA), a product
of carbon dioxide fixation; in the absence of PGA, the enzyme
exhibits only about 3% of its activity. Plant AGPase is also
strongly inhibited by inorganic phosphate (Pi). In contrast,
bacterial and algal AGPase exist as homotetramers of 50 kDa. The
algal enzyme, like its plant counterpart, is activated by PGA and
inhibited by Pi, whereas the bacterial enzyme is activated by
fructose-1, 6-bisphosphate (FBP) and inhibited by AMP and Pi.
[1033] As used herein, the term "polypeptide involved in the
degradation of lipid and/or which reduces lipid content" refers to
any polypeptide, the downregulation of which in a cell below normal
(wild-type) levels results an increase in the level of oil, such as
fatty acids and/or TAGs, in the cell, preferably a cell of
vegetative tissue of a plant. Examples of such polypeptides
include, but are not limited, lipases, or a lipase such as CGi58
polypeptide, SUGAR-DEPENDENT1 triacylglycerol lipase (see, for
example, Kelly et al., 2012) or a lipase described in WO
2009/027335.
[1034] As used herein, the term "lipase" refers to a protein which
hydrolyzes fats into glycerol and fatty acids. Thus, the term
"lipase activity" refers to the hydrolysis of fats into glycerol
and fatty acids.
[1035] As used herein, the term "CGi58" refers to a soluble
acyl-CoA-dependent lysophosphatidic acid acyltransferase also known
in the art art as "At4g24160" (in plants) and "Ict1p" (in yeast).
The plant gene such as that from Arabidopsis gene locus, At4g24160,
is expressed as two alternative transcripts: a longer full-length
isoform (At4g24160.1) and a smaller isoform (At4g24160.2) missing a
portion of the 3' end (see James et al., 2010; Ghosh et al., 2009;
US 201000221400). Both mRNAs code for a protein that is homologous
to the human CGI-58 protein and other orthologous members of this
.alpha./.beta. hydrolase family (ABHD). In an embodiment, the CGI58
(At4g24160) protein contains three motifs that are conserved across
plant species: a GXSXG lipase motif (SEQ ID NO:419), a HX(4)D
acyltransferase motif (SEQ ID NO:420), and VX(3)HGF, a probable
lipid binding motif (SEQ ID NO:421). The human CGI-58 protein has
lysophosphatidic acid acyltransferase (LPAAT) activity but not
lipase activity. In contrast, the plant and yeast proteins possess
a canonical lipase sequence motif GXSXG (SEQ ID NO:419), that is
absent from vertebrate (humans, mice, and zebrafish) proteins.
Although the plant and yeast CGI58 proteins appear to possess
detectable amounts of TAG lipase and phospholipase A activities in
addition to LPAAT activity, the human protein does not.
[1036] Disruption of the homologous CGI-58 gene in Arabidopsis
thaliana results in the accumulation of neutral lipid droplets in
mature leaves. Mass spectroscopy of isolated lipid droplets from
cgi-58 loss-of-function mutants showed they contain
triacylglycerols with common leaf-specific fatty acids. Leaves of
mature cgi-58 plants exhibit a marked increase in absolute
triacylglycerol levels, more than 10-fold higher than in wild-type
plants. Lipid levels in the oil-storing seeds of cgi-58
loss-of-function plants were unchanged, and unlike mutations in
.beta.-oxidation, the cgi-58 seeds germinated and grew normally,
requiring no rescue with sucrose (James et al., 2010).
[1037] Examples of CGi58 polypeptides include proteins from
Arabidopsis thaliana (NP_194147.2; SEQ ID NO:429), Brachypodium
distachyon (XP_003578450.1; SEQ ID NO:430), Glycine max
(XP_003523638.1; SEQ ID NO:431), Zea mays (NP_001149013.1; SEQ ID
NO:432), Sorghum bicolor (XP_002460538.1; SEQ ID NO:433), Ricinus
communis (XP_002510485.1; SEQ ID NO:434), Medicago truncatula
(XP_003603733.1; SEQ ID NO:435), and Oryza sativa (EAZ09782.1; SEQ
ID NO:436).
[1038] As used herein, the term "Leafy Cotyledon 2" or "LEC2"
refers to a B3 domain transcription factor which participates in
zygotic and in somatic embryogenesis. Its ectopic expression
facilitates the embryogenesis from vegetative plant tissues
(Alemanno et al., 2008). LEC2 also comprises a DNA binding region
found thus far only in plant proteins. Examples of LEC2
polypeptides include proteins from Arabidopsis thaliana
(NP_564304.1) (SEQ ID NO:442), Medicago truncatula (CAA42938.1)
(SEQ ID NO:443) and Brassica napus (AD016343.1) (SEQ ID
NO:444).
[1039] As used herein, the term "BABY BOOM" or "BBM" refers an
AP2/ERF transcription factor that induces regeneration under
culture conditions that normally do not support regeneration in
wild-type plants. Ectopic expression of Brassica napus BBM (BnBBM)
genes in B. napus and Arabidopsis induces spontaneous somatic
embryogenesis and organogenesis from seedlings grown on
hormone-free basal medium (Boutilier et al., 2002). In tobacco,
ectopic BBM expression is sufficient to induce adventitious shoot
and root regeneration on basal medium, but exogenous cytokinin is
required for somatic embryo (SE) formation (Srinivasan et al.,
2007). Examples of BBM polypeptides include proteins from
Arabidopsis thaliana (NP_197245.2) (SEQ ID NO:445) and Medicago
truncatula (AAW82334.1) (SEQ ID NO:446).
[1040] As used herein, the term "FAD2" refers to a membrane bound
delta-12 fatty acid desturase that desaturates oleic acid
(18:1.sup..DELTA.9) to produce linoleic acid
(C18:2.sup..DELTA.9,12).
[1041] As used herein, the term "epoxygenase" or "fatty acid
epoxygenase" refers to an enzyme that introduces an epoxy group
into a fatty acid resulting in the production of an epoxy fatty
acid. In preferred embodiment, the epoxy group is introduced at the
12th carbon on a fatty acid chain, in which case the epoxygenase is
a .DELTA.12-epoxygenase, especially of a C16 or C18 fatty acid
chain. The epoxygenase may be a .DELTA.9-epoxygenase, a .DELTA.15
epoxygenase, or act at a different position in the acyl chain as
known in the art. The epoxygenase may be of the P450 class.
Preferred epoxygenases are of the mono-oxygenase class as described
in WO98/46762. Numerous epoxygenases or presumed epoxygenases have
been cloned and are known in the art. Further examples of
expoxygenases include proteins comprising an amino acid sequence
provided in SEQ ID NO:21 of WO 2009/129582, polypeptides encoded by
genes from Crepis paleastina (CAA76156, Lee et al., 1998), Stokesia
laevis (AAR23815, Hatanaka et al., 2004) (monooxygenase type),
Euphorbia lagascae (AAL62063) (P450 type), human CYP2J2
(arachidonic acid epoxygenase, U37143); human CYPIA1 (arachidonic
acid epoxygenase, K03191), as well as variants and/or mutants
thereof.
[1042] As used herein, the term, "hydroxylase" or "fatty acid
hydroxylase" refers to an enzyme that introduces a hydroxyl group
into a fatty acid resulting in the production of a hydroxylated
fatty acid. In a preferred embodiment, the hydroxyl group is
introduced at the 2nd, 12th and/or 17th carbon on a C18 fatty acid
chain. Preferably, the hydroxyl group is introduced at the
12.sup.th carbon, in which case the hydroxylase is a
.DELTA.12-hydroxylase. In another preferred embodiment, the
hydroxyl group is introduced at the 15th carbon on a C16 fatty acid
chain. Hydroxylases may also have enzyme activity as a fatty acid
desaturase. Examples of genes encoding .DELTA.12-hydroxylases
include those from Ricinus communis (AAC9010, van de Loo 1995);
Physaria lindheimeri, (ABQ01458, Dauk et al., 2007); Lesquerella
fendleri, (AAC32755, Broun et al., 1998); Daucus carola,
(AAK30206); fatty acid hydroxylases which hydroxylate the terminus
of fatty acids, for example: A, thaliana CYP86A1 (P48422, fatty
acid .omega.-hydroxylase); Vicia saliva CYP94A1 (P98188, fatty acid
.omega.-hydroxylase); mouse CYP2E1 (X62595, lauric acid .omega.-I
hydroxylase); rat CYP4A1 (M57718, fatty acid .omega.-hydroxylase),
as well as as variants and/or mutants thereof.
[1043] As used herein, the term "conjugase" or "fatty acid
conjugase" refers to an enzyme capable of forming a conjugated bond
in the acyl chain of a fatty acid. Examples of conjugases include
those encoded by genes from Calendula officinalis (AF343064, Qiu et
al., 2001); Vernicia fordii (AAN87574, Dyer et al., 2002); Punica
granatum (AY178446, Iwabuchi et al., 2003) and Trichosanthes
kirilowii (AY178444, Iwabuchi et al., 2003); as well as as variants
and/or mutants thereof.
[1044] As used herein, the term "acetylenase" or "fatty acid
acetylenase" refers to an enzyme that introduces a triple bond into
a fatty acid resulting in the production of an acetylenic fatty
acid. In a preferred embodiment, the triple bond is introduced at
the 2nd, 6th, 12th and/or 17th carbon on a C18 fatty acid chain.
Examples acetylenases include those from Helianthus annuus
(AA038032, ABC59684), as well as as variants and/or mutants
thereof.
[1045] Examples of such fatty acid modifying genes include proteins
according to the following Accession Numbers which are grouped by
putative function, and homologues from other species: .DELTA.12
acetylenases ABC00769, CAA76158, AA038036, AA038032; .DELTA.12
conjugases AAG42259, AAG42260, AAN87574; .DELTA.12 desaturases
P46313, ABS18716, AAS57577, AAL61825, AAF04093, AAF04094; .DELTA.12
epoxygenases XP_001840127, CAA76156, AAR23815; .DELTA.12
hydroxylases ACF37070, AAC32755, ABQ01458, AAC49010; and .DELTA.12
P450 enzymes such as AF406732.
[1046] As used herein, the term "vegetative tissue" or "vegetative
plant part" is any plant tissue, organ or part other than organs
for sexual reproduction of plants, specifically seed bearing
organs, flowers, pollen, fruits and seeds. Vegetative tissues and
parts include at least plant leaves, stems (including bolts and
tillers but excluding the heads), tubers and roots, but excludes
flowers, pollen, seed including the seed coat, embryo and
endosperm, fruit including mesocarp tissue, seed-bearing pods and
seed-bearing heads. In one embodiment, the vegetative part of the
plant is an aerial plant part. In another or further embodiment,
the vegetative plant part is a green part such as a leaf or
stem.
[1047] As used herein, the term "wild-type" or variations thereof
refers to a cell, or non-human organism or part thereof that has
not been genetically modified.
[1048] The term "corresponding" refers to a vegetative plant part,
a cell, or non-human organism or part thereof; or seed that has the
same or similar genetic background as a vegetative plant part, a
cell, or non-human organism or part thereof or seed of the
invention but that has not been modified as described herein (for
example, a vegetative plant part, a cell, or non-human organism or
part thereof, or seed lacks an exogenous polynucleotide encoding a
MGAT or an exogenous MGAT). In a preferred embodiment, a vegetative
plant part, a cell, or non-human organism or part thereof, or seed
is at the same developmental stage as a vegetative plant part, a
cell, or non-human organism or part thereof, or seed of the
invention. For example, if the non-human organism is a flowering
plant, then preferably the corresponding plant is also flowering. A
corresponding a vegetative plant part, a cell, or non-human
organism or part thereof, or seed can be used as a control to
compare levels of nucleic acid or protein expression, or the extent
and nature of trait modification, for example non-polar lipid
production and/or content, with a vegetative plant part, a cell, or
non-human organism or part thereof, or seed modified as described
herein. A person skilled in the art is readily able to determine an
appropriate "corresponding" cell, tissue, organ or organism for
such a comparison.
[1049] As used herein "compared with" refers to comparing levels of
a non-polar lipid or total non-polar lipid content of the
transgenic non-human organism or part thereof expressing the one or
more exogenous polynucleotides or exogenous polypeptides with a
transgenic non-human organism or part thereof lacking the one or
more exogenous polynucelotides or polypeptides.
[1050] As used herein, "enhanced ability to produce non-polar
lipid" is a relative term which refers to the total amount of
non-polar lipid being produced by a cell, or non-human organism or
part thereof of the invention being increased relative to a
corresponding cell, or non-human organism or part thereof. In one
embodiment, the TAG and/or polyunsaturated fatty acid content of
the non-polar lipid is increased.
[1051] As used herein, "germinate at a rate substantially the same
as for a corresponding wild-type plant" refers to seed of a plant
of the invention being relatively fertile when compared to seed of
a wild type plant lacking the defined exogenous polynucleotide(s).
In one embodiment, the number of seeds which germinate, for
instance when grown under optimal greenhouse conditions for the
plant species, is at least 75%, more preferably at least 90%, of
that when compared to corresponding wild-type seed. In another
embodiment, the seeds which germinate, for instance when grown
under optimal greenhouse conditions for the plant species, grow at
a rate which, on average, is at least 75%, more preferably at least
90%, of that when compared to corresponding wild-type plants.
[1052] As used herein, the term "an isolated or recombinant
polynucleotide which down regulates the production and/or activity
of an endogenous enzyme" or variations thereof, refers to a
polynucleotide that encodes an RNA molecule that down regulates the
production and/or activity (for example, encoding an siRNA,
hpRNAi), or itself down regulates the production and/or activity
(for example, is an siRNA which can be delivered directly to, for
example, a cell) of an endogenous enzyme for example, DGAT, sn-1
glycerol-3-phosphate acyltransferase (GPAT),
1-acyl-glycerol-3-phosphate acyltransferase (LPAAT),
acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT),
phosphatidic acid phosphatase (PAP), AGPase, or delta-12 fatty acid
desturase (FAD2), or a combination of two or more thereof.
[1053] As used herein, the term "on a weight basis" refers to the
weight of a substance (for example, TAG, DAG, fatty acid) as a
percentage of the weight of the composition comprising the
substance (for example, seed, leaf). For example, if a transgenic
seed has 25 .mu.g total fatty acid per 120 .mu.g seed weight; the
percentage of total fatty acid on a weight basis is 20.8%.
[1054] As used herein, the term "on a relative basis" refers to the
amount of a substance in a composition comprising the substance in
comparison with a corresponding composition, as a percentage.
[1055] As used herein, the term "the relative non-lipid content"
refers to the expression of the non-polar lipid content of a cell,
organism or part thereof, or extracted lipid therefrom, in
comparison with a corresponding cell, organism or part thereof, or
the lipid extracted from the corresponding cell, organism or part
thereof, as a percentage. For example, if a transgenic seed has 25
.mu.g total fatty acid, whilst the corresponding seed had 20 .mu.g
total fatty acid; the increase in non-polar lipid content on a
relative basis equals 25%.
[1056] As used herein, the term "biofuel" refers to any type of
fuel, typically as used to power machinery such as automobiles,
trucks or petroleum powered motors, whose energy is derived from
biological carbon fixation. Biofuels include fuels derived from
biomass conversion, as well as solid biomass, liquid fuels and
biogases. Examples of biofuels include bioalcohols, biodiesel,
synthetic diesel, vegetable oil, bioethers, biogas, syngas, solid
biofuels, algae-derived fuel, biohydrogen, biomethanol,
2,5-Dimethylfuran (DMF), biodimethyl ether (bioDME),
Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood
diesel.
[1057] As used herein, the term "bioalcohol" refers to biologically
produced alcohols, for example, ethanol, propanol and butanol.
Bioalcohols are produced by the action of microorganisms and/or
enzymes through the fermentation of sugars, hemicellulose or
cellulose.
[1058] As used herein, the term "biodiesel" refers to a composition
comprising fatty acid methyl- or ethyl-esters derived from
non-polar lipids by transesterification.
[1059] As used herein, the term "synthetic diesel" refers to a form
of diesel fuel which is derived from renewable feedstock rather
than the fossil feedstock used in most diesel fuels.
[1060] As used herein, the term "vegetable oil" includes a pure
plant oil (or straight vegetable oil) or a waste vegetable oil (by
product of other industries).
[1061] As used herein, the term "bioethers" refers to compounds
that act as octane rating enhancers.
[1062] As used herein, the term "biogas" refers to methane or a
flammable mixture of methane and other gases produced by anaerobic
digestion of organic material by anaerobes.
[1063] As used herein, the term "syngas" refers to a gas mixture
that contains varying amounts of carbon monoxide and hydrogen and
possibly other hydrocarbons, produced by partial combustion of
biomass.
[1064] As used herein, the term "solid biofuels" includes wood,
sawdust, grass trimmining, and non-food energy crops.
[1065] As used herein, the term "cellulosic ethanol" refers to
ethanol produced from cellulose or hemicellulose.
[1066] As used herein, the term "algae fuel" refers to a biofuel
made from algae and includes algal biodiesel, biobutanol,
biogasoline, methane, ethanol, and the equivalent of vegetable oil
made from algae.
[1067] As used herein, the term "biohydrogen" refers to hydrogen
produced biologically by, for example, algae.
[1068] As used herein, the term "biomethanol" refers to methanol
produced biologically. Biomethanol may be produced by gasification
of organic materials to syngas followed by conventional methanol
synthesis.
[1069] As used herein, the term "2,5-Dimethylfuran" or "DMF" refers
to a heterocyclic compound with the formula
(CH.sub.3).sub.2C.sub.4H.sub.2O. DMF is a derivative of furan that
is derivable from cellulose.
[1070] As used herein, the term "biodimethyl ether" or "bioDME",
also known as methoxymethane, refers to am organic compound with
the formula CH.sub.3OCH.sub.3. Syngas may be converted into
methanol in the presence of catalyst (usually copper-based), with
subsequent methanol dehydration in the presence of a different
catalyst (for example, silica-alumina) resulting in the production
of DME.
[1071] As used herein, the term "Fischer-Tropsch" refers to a set
of chemical reactions that convert a mixture of carbon monoxide and
hydrogen into liquid hydrocarbons. The syngas can first be
conditioned using for example, a water gas shift to achieve the
required H.sub.2/CO ratio. The conversion takes place in the
presence of a catalyst, usually iron or cobalt. The temperature,
pressure and catalyst determine whether a light or heavy syncrude
is produced. For example at 330.degree. C. mostly gasoline and
olefins are produced whereas at 180.degree. to 250.degree. C.
mostly diesel and waxes are produced. The liquids produced from the
syngas, which comprise various hydrocarbon fractions, are very
clean (sulphur free) straight-chain hydrocarbons. Fischer-Tropsch
diesel can be produced directly, but a higher yield is achieved if
first Fischer-Tropsch wax is produced, followed by
hydrocracking.
[1072] As used herein, the term "biochar" refers to charcoal made
from biomass, for example, by pyrolysis of the biomass.
[1073] As used herein, the term "feedstock" refers to a material,
for example, biomass or a conversion product thereof (for example,
syngas) when used to produce a product, for example, a biofuel such
as biodiesel or a synthetic diesel.
[1074] As used herein, the term "industrial product" refers to a
hydrocarbon product which is predominantly made of carbon and
hydrogen such as fatty acid methyl- and/or ethyl-esters or alkanes
such as methane, mixtures of longer chain alkanes which are
typically liquids at ambient temperatures, a biofuel, carbon
monoxide and/or hydrogen, or a bioalcohol such as ethanol,
propanol, or butanol, or biochar. The term "industrial product" is
intended to include intermediary products that can be converted to
other industrial products, for example, syngas is itself considered
to be an industrial product which can be used to synthesize a
hydrocarbon product which is also considered to be an industrial
product. The term industrial product as used herein includes both
pure forms of the above compounds, or more commonly a mixture of
various compounds and components, for example the hydrocarbon
product may contain a range of carbon chain lengths, as well
understood in the art.
[1075] As used herein, "gloss" refers to an optical phenomenon
caused when evaluating the appearance of a surface. The evaluation
of gloss describes the capacity of a surface to reflect directed
light.
[1076] Throughout this specification the word "comprise", or
variations such as "comprises" or "comprising", will be understood
to imply the inclusion of a stated element, integer or step, or
group of elements, integers or steps, but not the exclusion of any
other element, integer or step, or group of elements, integers or
steps.
[1077] The term "and/or", e.g., "X and/or Y" shall be understood to
mean either "X and Y" or "X or Y" and shall be taken to provide
explicit support for both meanings or for either meaning.
[1078] As used herein, the term about, unless stated to the
contrary, refers to +/-10%, more preferably +/-5%, more preferably
+/-2%, more preferably +/-1%, even more preferably +/-0.5%, of the
designated value.
Production of Diacylgylerols and Triacyglycerols
[1079] In one embodiment, the vegetative plant part, transgenic
non-human organism or part thereof of the invention produces higher
levels of non-polar lipids such as DAG or TAG, preferably both,
than a corresponding vegetative plant part, non-human organism or
part thereof. In one example, transgenic plants of the invention
produce seeds, leaves, leaf portions of at least 1 cm.sup.2 in
surface area, stems and/or tubers having an increased non-polar
lipid content such as DAG or TAG, preferably both, when compared to
corresponding seeds, leaves, leaf portions of at least 1 cm.sup.2
in surface area, stems or tubers. The non-polar lipid content of
the vegetative plant part, non-human organism or part thereof is at
0.5% greater on a weight basis when compared to a corresponding
non-human organism or part thereof, or as further defined in
Feature (i).
[1080] In another embodiment, the vegetative plant part, transgenic
non-human organism or part thereof, preferably a plant or seed,
produce DAGs and/or TAGs that are enriched for one or more
particular fatty acids. A wide spectrum of fatty acids can be
incorporated into DAGs and/or TAGs, including saturated and
unsaturated fatty acids and short-chain and long-chain fatty acids.
Some non-limiting examples of fatty acids that can be incorporated
into DAGs and/or TAGs and which may be increased in level include:
capric (10:0), lauric (12:0), myristic (14:0), palmitic (16:0),
palmitoleic (16:1), stearic (18:0), oleic (18:1), vaccenic (18:1),
linoleic (18:2), eleostearic (18:3), .gamma.-linolenic (18:3),
.alpha.-linolenic (18:3.omega.3), stearidonic (18:4.omega.3),
arachidic (20:0), eicosadienoic (20:2), dihomo-.gamma.-linoleic
(20:3), eicosatrienoic (20:3), arachidonic (20:4), eicosatetraenoic
(20:4), eicosapentaenoic (20:5.omega.3), behenic (22:0),
docosapentaenoic (22:5.omega.), docosahexaenoic (22:6.omega.3),
lignoceric (24:0), nervonic (24:1), cerotic (26:0), and montanic
(28:0) fatty acids. In one embodiment of the present invention, the
vegetative plant part, transgenic organism or parts thereof is
enriched for DAGs and/or TAGs comprising oleic acid, or
polyunsaturated fatty acids.
[1081] In one embodiment of the invention, the vegetative plant
part, transgenic non-human organism or part thereof, preferably a
plant or seed, is transformed with a chimeric DNA which encodes an
MGAT which may or may not have DGAT activity. Expression of the
MGAT preferably results in higher levels of non-polar lipids such
as DAG or TAG and/or increased non-polar lipid yield in said
vegetative plant part, transgenic non-human organism or part
thereof. In a preferred embodiment, the transgenic non-human
organism is a plant.
[1082] In a further embodiment, the vegetative plant part,
transgenic non-human organism or part thereof is transformed with a
chimeric DNA which encodes a GPAT or a DGAT. Preferably, the
vegetative plant part or transgenic non-human organism is
transformed with both chimeric DNAs, which are preferably
covalently linked on one DNA molecule such as, for example, a
single T-DNA molecule.
[1083] Yang et al. (2010) describe two glycerol-3-phosphate
acyltransferases (GPAT4 and GPAT6) from Arabidopsis with sn-2
preference and phosphatase activity that are able to produce sn-2
MAG from glycerol-3-phosphate (G-3-P) (FIG. 1). These enzymes are
proposed to be part of the cutin synthesis pathway. Arabidopsis
GPAT4 and GPAT6 have been shown to use acyl-CoA as a fatty acid
substrate (Zheng et al., 2003).
[1084] Combining a bifunctional GPAT/phosphatase with a MGAT yields
a novel DAG synthesis pathway using G-3-P as one substrate and two
acyl groups derived from acyl-CoA as the other substrates.
Similarly, combining such a bifunctional GPAT/phosphatase with a
MGAT which has DGAT activity yields a novel TAG synthesis pathway
using glycerol-3-phosphate as one substrate and three acyl groups
derived from acyl-CoA as other substrates.
[1085] Accordingly, in one embodiment of the invention, the
vegetative plant part, transgenic non-human organism or part
thereof is co-transformed with a bifunctional GPAT/phosphatase and
with a MGAT which does not have DGAT activity. This would result in
the production of MAG by the bifunctional GPAT/phosphatase which
would then be converted to DAG by the MGAT and then TAG by a native
DGAT or other activity. Novel DAG production could be confirmed and
selected for by, for example, performing such a co-transformation
in a yeast strain containing lethal SLC1+SLC4 knockouts such as
that described by Benghezal et al. (2007; FIG. 2). FIG. 2 of
Benghezal et al. (2007) shows that knocking out the two yeast LPATS
(SLC1 & SLC4) is lethal. The SLC+SLC4 double yeast mutant can
only be maintained because of a complementing plasmid which
provides one of the sic genes (SLC1 in their case) in trans.
Negative selection by adding FOA to the medium results in the loss
of this complementing plasmid (counterselection of the Ura
selection marker) and renders the cells non viable.
[1086] In another embodiment of the invention, the vegetative plant
part, transgenic non-human organism or part thereof, preferably a
plant or seed, is co-transformed with chimeric DNAs encoding a
bifunctional GPAT/phosphatase and a MGAT which has DGAT activity.
This would result in the production of MAG by the bifunctional
GPAT/phosphatase which would then be converted to DAG and then TAG
by the MGAT.
[1087] In a further embodiment, one or more endogenous GPATs with
no detectable phosphatase activity are silenced, for example one or
more genes encoding GPATs that acylate glycerol-3-phosphate to form
LPA in the Kennedy Pathway (for example, Arabidopsis GPAT1) is
silenced.
[1088] In another embodiment, the vegetative plant part, transgenic
non-human organism or part thereof, preferably a plant or seed, is
transformed with a chimeric DNAs encoding a DGAT1, a DGAT2, a
Wrinkled 1 (WRI1) transcription factor, an Oleosin, or a silencing
suppressor polypeptide. The chimeric DNAs are preferably covalently
linked on one DNA molecule such as, for example, a single T-DNA
molecule, and the vegetative plant part, transgenic non-human
organism or part thereof is preferably homozygous for the one DNA
molecule inserted into its genome.
[1089] Substrate preferences could be engineered into the novel DAG
and TAG synthesis pathways by, for example, supplying transgenic
H1246 yeast strains expressing MGAT variants with a concentration
of a particular free fatty acid (for example, DHA) that prevents
complementation by the wildtype MGAT gene. Only the variants able
to use the supplied free fatty acid would grow. Several cycles of
MGAT engineering would result in the production of a MGAT with
increased preference for particular fatty acids.
[1090] The various Kennedy Pathway complementations and
supplementations described above could be performed in any cell
type due to the ubiquitous nature of the initial substrate
glycerol-3-phosphate. In one embodiment, the use of transgenes
results in increased oil yields.
Polynucleotides
[1091] The terms "polynucleotide", and "nucleic acid" are used
interchangeably. They refer to a polymeric form of nucleotides of
any length, either deoxyribonucleotides or ribonucleotides, or
analogs thereof. A polynucleotide of the invention may be of
genomic, cDNA, semisynthetic, or synthetic origin, double-stranded
or single-stranded and by virtue of its origin or manipulation: (1)
is not associated with all or a portion of a polynucleotide with
which it is associated in nature, (2) is linked to a polynucleotide
other than that to which it is linked in nature, or (3) does not
occur in nature. The following are non-limiting examples of
polynucleotides: coding or non-coding regions of a gene or gene
fragment, loci (locus) defined from linkage analysis, exons,
introns, messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA
(rRNA), ribozymes, cDNA, recombinant polynucleotides, branched
polynucleotides, plasmids, vectors, isolated DNA of any sequence,
isolated RNA of any sequence, chimeric DNA of any sequence, nucleic
acid probes, and primers. A polynucleotide may comprise modified
nucleotides such as methylated nucleotides and nucleotide analogs.
If present, modifications to the nucleotide structure may be
imparted before or after assembly of the polymer. The sequence of
nucleotides may be interrupted by non-nucleotide components. A
polynucleotide may be further modified after polymerization such as
by conjugation with a labeling component.
[1092] By "isolated polynucleotide" it is meant a polynucleotide
which has generally been separated from the polynucleotide
sequences with which it is associated or linked in its native
state. Preferably, the isolated polynucleotide is at least 60%
free, more preferably at least 75% free, and more preferably at
least 90% free from the polynucleotide sequences with which it is
naturally associated or linked.
[1093] As used herein, the term "gene" is to be taken in its
broadest context and includes the deoxyribonucleotide sequences
comprising the transcribed region and, if translated, the protein
coding region, of a structural gene and including sequences located
adjacent to the coding region on both the 5' and 3' ends for a
distance of at least about 2 kb on either end and which are
involved in expression of the gene. In this regard, the gene
includes control signals such as promoters, enhancers, termination
and/or polyadenylation signals that are naturally associated with a
given gene, or heterologous control signals, in which case, the
gene is referred to as a "chimeric gene". The sequences which are
located 5' of the protein coding region and which are present on
the mRNA are referred to as 5' non-translated sequences. The
sequences which are located 3' or downstream of the protein coding
region and which are present on the mRNA are referred to as 3'
non-translated sequences. The term "gene" encompasses both cDNA and
genomic forms of a gene. A genomic form or clone of a gene contains
the coding region which may be interrupted with non-coding
sequences termed "introns", "intervening regions", or "intervening
sequences." Introns are segments of a gene which are transcribed
into nuclear RNA (nRNA). Introns may contain regulatory elements
such as enhancers. Introns are removed or "spliced out" from the
nuclear or primary transcript; introns therefore are absent in the
mRNA transcript. The mRNA functions during translation to specify
the sequence or order of amino acids in a nascent polypeptide. The
term "gene" includes a synthetic or fusion molecule encoding all or
part of the proteins of the invention described herein and a
complementary nucleotide sequence to any one of the above.
[1094] As used herein, "chimeric DNA" refers to any DNA molecule
that is not naturally found in nature; also referred to herein as a
"DNA construct". Typically, chimeric DNA comprises regulatory and
transcribed or protein coding sequences that are not naturally
found together in nature. Accordingly, chimeric DNA may comprise
regulatory sequences and coding sequences that are derived from
different sources, or regulatory sequences and coding sequences
derived from the same source, but arranged in a manner different
than that found in nature. The open reading frame may or may not be
linked to its natural upstream and downstream regulatory elements.
The open reading frame may be incorporated into, for example, the
plant genome, in a non-natural location, or in a replicon or vector
where it is not naturally found such as a bacterial plasmid or a
viral vector. The term "chimeric DNA" is not limited to DNA
molecules which are replicable in a host, but includes DNA capable
of being ligated into a replicon by, for example, specific adaptor
sequences.
[1095] A "transgene" is a gene that has been introduced into the
genome by a transformation procedure. The term includes a gene in a
progeny cell, plant, seed, non-human organism or part thereof which
was introducing into the genome of a progenitor cell thereof. Such
progeny cells etc may be at least a 3.sup.rd or 4.sup.th generation
progeny from the progenitor cell which was the primary transformed
cell. Progeny may be produced by sexual reproduction or
vegetatively such as, for example, from tubers in potatoes or
ratoons in sugarcane. The term "genetically modified", and
variations thereof; is a broader term that includes introducing a
gene into a cell by transformation or transduction, mutating a gene
in a cell and genetically altering or modulating the regulation of
a gene in a cell, or the progeny of any cell modified as described
above.
[1096] A "genomic region" as used herein refers to a position
within the genome where a transgene, or group of transgenes (also
referred to herein as a cluster), have been inserted into a cell,
or predecessor thereof. Such regions only comprise nucleotides that
have been incorporated by the intervention of man such as by
methods described herein.
[1097] A "recombinant polynucleotide" of the invention refers to a
nucleic acid molecule which has been constructed or modified by
artificial recombinant methods.
[1098] The recombinant polynucleotide may be present in a cell in
an altered amount or expressed at an altered rate (e.g., in the
case of mRNA) compared to its native state. In one embodiment, the
polynucleotide is introduced into a cell that does not naturally
comprise the polynucleotide. Typically an exogenous DNA is used as
a template for transcription of mRNA which is then translated into
a continuous sequence of amino acid residues coding for a
polypeptide of the invention within the transformed cell. In
another embodiment, the polynucleotide is endogenous to the cell
and its expression is altered by recombinant means, for example, an
exogenous control sequence is introduced upstream of an endogenous
gene of interest to enable the transformed cell to express the
polypeptide encoded by the gene.
[1099] A recombinant polynucleotide of the invention includes
polynucleotides which have not been separated from other components
of the cell-based or cell-free expression system, in which it is
present, and polynucleotides produced in said cell-based or
cell-free systems which are subsequently purified away from at
least some other components. The polynucleotide can be a contiguous
stretch of nucleotides existing in nature, or comprise two or more
contiguous stretches of nucleotides from different sources
(naturally occurring and/or synthetic) joined to form a single
polynucleotide. Typically, such chimeric polynucleotides comprise
at least an open reading frame encoding a polypeptide of the
invention operably linked to a promoter suitable of driving
transcription of the open reading frame in a cell of interest.
[1100] With regard to the defined polynucleotides, it will be
appreciated that % identity figures higher than those provided
above will encompass preferred embodiments. Thus, where applicable,
in light of the minimum % identity figures, it is preferred that
the polynucleotide comprises a polynucleotide sequence which is at
least 60%, more preferably at least 65%, more preferably at least
70%, more preferably at least 75%, more preferably at least 80%,
more preferably at least 85%, more preferably at least 90%, more
preferably at least 91%, more preferably at least 92%, more
preferably at least 93%, more preferably at least 94%, more
preferably at least 95%, more preferably at least 96%, more
preferably at least 97%, more preferably at least 98%, more
preferably at least 99%, more preferably at least 99.1%, more
preferably at least 99.2%, more preferably at least 99.3%, more
preferably at least 99.4%, more preferably at least 99.5%, more
preferably at least 99.6%, more preferably at least 99.7%, more
preferably at least 99.8%, and even more preferably at least 99.9%
identical to the relevant nominated SEQ ID NO.
[1101] A polynucleotide of, or useful for, the present invention
may selectively hybridise, under stringent conditions, to a
polynucleotide defined herein. As used herein, stringent conditions
are those that: (1) employ during hybridisation a denaturing agent
such as formamide, for example, 50% (v/v) formamide with 0.1% (w/v)
bovine serum albumin, 0.1% Ficoll, 0.1% polyvinylpyrrolidone, 50 mM
sodium phosphate buffer at pH 6.5 with 750 mM NaCl, 75 mM sodium
citrate at 42.degree. C.; or (2) employ 50% formamide, 5.times.SSC
(0.75 M NaCl, 0.075 M sodium citrate), 50 mM sodium phosphate (pH
6.8), 0.1% sodium pyrophosphate, 5.times.Denhardt's solution,
sonicated salmon sperm DNA (50 g/ml), 0.1% SDS and 10% dextran
sulfate at 42.degree. C. in 0.2.times.SSC and 0.1% SDS, and/or (3)
employ low ionic strength and high temperature for washing, for
example, 0.015 M NaCl/0.0015 M sodium citrate/0.1% SDS at
50.degree. C.
[1102] Polynucleotides of the invention may possess, when compared
to naturally occurring molecules, one or more mutations which are
deletions, insertions, or substitutions of nucleotide residues.
Polynucleotides which have mutations relative to a reference
sequence can be either naturally occurring (that is to say,
isolated from a natural source) or synthetic (for example, by
performing site-directed mutagenesis or DNA shuffling on the
nucleic acid as described above).
Polynucleotide for Reducing Expression Levels of Endogenous
Proteins
RNA Interference
[1103] RNA interference (RNAi) is particularly useful for
specifically inhibiting the production of a particular protein.
Although not wishing to be limited by theory, Waterhouse et al.
(1998) have provided a model for the mechanism by which dsRNA
(duplex RNA) can be used to reduce protein production. This
technology relies on the presence of dsRNA molecules that contain a
sequence that is essentially identical to the mRNA of the gene of
interest or part thereof. Conveniently, the dsRNA can be produced
from a single promoter in a recombinant vector or host cell, where
the sense and anti-sense sequences are flanked by an unrelated
sequence which enables the sense and anti-sense sequences to
hybridize to form the dsRNA molecule with the unrelated sequence
forming a loop structure. The design and production of suitable
dsRNA molecules is well within the capacity of a person skilled in
the art, particularly considering Waterhouse et al. (1998), Smith
et al. (2000), WO 99/32619, WO 99/53050, WO 99/49029, and WO
01/34815.
[1104] In one example, a DNA is introduced that directs the
synthesis of an at least partly double stranded RNA product(s) with
homology to the target gene to be inactivated. The DNA therefore
comprises both sense and antisense sequences that, when transcribed
into RNA, can hybridize to form the double stranded RNA region. In
one embodiment of the invention, the sense and antisense sequences
are separated by a spacer region that comprises an intron which,
when transcribed into RNA, is spliced out. This arrangement has
been shown to result in a higher efficiency of gene silencing. The
double stranded region may comprise one or two RNA molecules,
transcribed from either one DNA region or two. The presence of the
double stranded molecule is thought to trigger a response from an
endogenous system that destroys both the double stranded RNA and
also the homologous RNA transcript from the target gene,
efficiently reducing or eliminating the activity of the target
gene.
[1105] The length of the sense and antisense sequences that
hybridize should each be at least 19 contiguous nucleotides. The
full-length sequence corresponding to the entire gene transcript
may be used. The degree of identity of the sense and antisense
sequences to the targeted transcript should be at least 85%, at
least 90%, or at least 95-100%. The RNA molecule may of course
comprise unrelated sequences which may function to stabilize the
molecule. The RNA molecule may be expressed under the control of a
RNA polymerase II or RNA polymerase III promoter. Examples of the
latter include tRNA or snRNA promoters.
[1106] Preferred small interfering RNA ("siRNA") molecules comprise
a nucleotide sequence that is identical to about 19-21 contiguous
nucleotides of the target mRNA. Preferably, the siRNA sequence
commences with the dinucleotide AA, comprises a GC-content of about
30-70% (preferably, 30-60%, more preferably 40-60.degree. % and
more preferably about 45/%-55%), and does not have a high
percentage identity to any nucleotide sequence other than the
target in the genome of the organism in which it is to be
introduced, for example, as determined by standard BLAST
search.
microRNA
[1107] MicroRNAs (abbreviated miRNAs) are generally 19-25
nucleotides (commonly about 20-24 nucleotides in plants) non-coding
RNA molecules that are derived from larger precursors that form
imperfect stem-loop structures.
[1108] miRNAs bind to complementary sequences on target messenger
RNA transcripts (mRNAs), usually resulting in translational
repression or target degradation and gene silencing.
[1109] In plant cells, miRNA precursor molecules are believed to be
largely processed in the nucleus. The pri-miRNA (containing one or
more local double-stranded or "hairpin" regions as well as the
usual 5' "cap" and polyadenylated tail of an mRNA) is processed to
a shorter miRNA precursor molecule that also includes a stem-loop
or fold-back structure and is termed the "pre-miRNA". In plants,
the pre-miRNAs are cleaved by distinct DICER-like (DCL) enzymes,
yielding miRNA:miRNA*duplexes. Prior to transport out of the
nucleus, these duplexes are methylated.
[1110] In the cytoplasm, the miRNA strand from the miRNA:miRNA
duplex is selectively incorporated into an active RNA-induced
silencing complex (RISC) for target recognition. The RISC-complexes
contain a particular subset of Argonaute proteins that exert
sequence-specific gene repression (see, for example, Millar and
Waterhouse, 2005; Pasquinelli et al., 2005; Almeida and Allshire,
2005).
Cosuppression
[1111] Genes can suppress the expression of related endogenous
genes and/or transgenes already present in the genome, a phenomenon
termed homology-dependent gene silencing. Most of the instances of
homologydependent gene silencing fall into two classes--those that
function at the level of transcription of the transgene, and those
that operate post-transcriptionally.
[1112] Post-transcriptional homology-dependent gene silencing
(i.e., cosuppression) describes the loss of expression of a
transgene and related endogenous or viral genes in transgenic
plants. Cosuppression often, but not always, occurs when transgene
transcripts are abundant, and it is generally thought to be
triggered at the level of mRNA processing, localization, and/or
degradation. Several models exist to explain how cosuppression
works (see in Taylor, 1997).
[1113] One model, the "quantitative" or "RNA threshold" model,
proposes that cells can cope with the accumulation of large amounts
of transgene transcripts, but only up to a point Once that critical
threshold has been crossed, the sequence-dependent degradation of
both transgene and related endogenous gene transcripts is
initiated. It has been proposed that this mode of cosuppression may
be triggered following the synthesis of copy RNA (cRNA) molecules
by reverse transcription of the excess transgene mRNA, presumably
by endogenous RNA-dependent RNA polymerases. These cRNAs may
hybridize with transgene and endogenous mRNAs, the unusual hybrids
targeting homologous transcripts for degradation. However, this
model does not account for reports suggesting that cosuppression
can apparently occur in the absence of transgene transcription
and/or without the detectable accumulation of transgene
transcripts.
[1114] To account for these data, a second model, the "qualitative"
or "aberrant RNA" model, proposes that interactions between
transgene RNA and DNA and/or between endogenous and introduced DNAs
lead to the methylation of transcribed regions of the genes. The
methylated genes are proposed to produce RNAs that are in some way
aberrant, their anomalous features triggering the specific
degradation of all related transcripts. Such aberrant RNAs may be
produced by complex transgene loci, particularly those that contain
inverted repeats.
[1115] A third model proposes that intermolecular base pairing
between transcripts, rather than cRNA-mRNA hybrids generated
through the action of an RNA-dependent RNA polymerase, may trigger
cosuppression. Such base pairing may become more common as
transcript levels rise, the putative double-stranded regions
triggering the targeted degradation of homologous transcripts. A
similar model proposes intramolecular base pairing instead of
intermolecular base pairing between transcripts.
[1116] Cosuppression involves introducing an extra copy of a gene
or a fragment thereof into a plant in the sense orientation with
respect to a promoter for its expression. A skilled person would
appreciate that the size of the sense fragment, its correspondence
to target gene regions, and its degree of sequence identity to the
target gene can vary. In some instances, the additional copy of the
gene sequence interferes with the expression of the target plant
gene. Reference is made to WO 97/20936 and EP 0465572 for methods
of implementing co-suppression approaches.
Antisense Polynucleotides
[1117] The term "antisense polynucletoide" shall be taken to mean a
DNA or RNA, or combination thereof molecule that is complementary
to at least a portion of a specific mRNA molecule encoding an
endogenous polypeptide and capable of interfering with a
post-transcriptional event such as mRNA translation. The use of
antisense methods is well known in the art (see for example, G.
Hartmann and S. Endres, Manual of Antisense Methodology, Kluwer
(1999)). The use of antisense techniques in plants has been
reviewed by Bourque (1995) and Senior (1998). Bourque (1995) lists
a large number of examples of how antisense sequences have been
utilized in plant systems as a method of gene inactivation. Bourque
also states that attaining 100% inhibition of any enzyme activity
may not be necessary as partial inhibition will more than likely
result in measurable change in the system. Senior (1998) states
that antisense methods are now a very well established technique
for manipulating gene expression.
[1118] In one embodiment, the antisense polynucleotide hybridises
under physiological conditions, that is, the antisense
polynucleotide (which is fully or partially single stranded) is at
least capable of forming a double stranded polynucleotide with mRNA
encoding a protein such as an endogenous enzyme, for example, DGAT,
GPAT, LPAA, LPCAT, PAP, AGPase, under normal conditions in a
cell.
[1119] Antisense molecules may include sequences that correspond to
the structural genes or for sequences that effect control over the
gene expression or splicing event. For example, the antisense
sequence may correspond to the targeted coding region of endogenous
gene, or the 5'-untranslated region (UTR) or the 3'-UTR or
combination of these. It may be complementary in part to intron
sequences, which may be spliced out during or after transcription,
preferably only to exon sequences of the target gene. In view of
the generally greater divergence of the UTRs, targeting these
regions provides greater specificity of gene inhibition.
[1120] The length of the antisense sequence should be at least 19
contiguous nucleotides, preferably at least 50 nucleotides, and
more preferably at least 100, 200, 500 or 1000 nucleotides. The
full-length sequence complementary to the entire gene transcript
may be used. The length is most preferably 100-2000 nucleotides.
The degree of identity of the antisense sequence to the targeted
transcript should be at least 90% and more preferably 95-100%. The
antisense RNA molecule may of course comprise unrelated sequences
which may function to stabilize the molecule.
Catalytic Polynucleotides
[1121] The term "catalytic polynucleotide" refers to a DNA molecule
or DNA-containing molecule (also known in the art as a
"deoxyribozyme") or an RNA or RNA-containing molecule (also known
as a "ribozyme") which specifically recognizes a distinct substrate
and catalyses the chemical modification of this substrate. The
nucleic acid bases in the catalytic nucleic acid can be bases A, C,
G, T (and U for RNA).
[1122] Typically, the catalytic nucleic acid contains an antisense
sequence for specific recognition of a target nucleic acid, and a
nucleic acid cleaving enzymatic activity (also referred to herein
as the "catalytic domain"). The types of ribozymes that are
particularly useful in this invention are hammerhead ribozymes
(Haseloff and Gerlach, 1988; Perriman et al., 1992) and hairpin
ribozymes (Zolotukhin et al., 1996; Klein et al., 1998; Shippy et
al., 1999).
[1123] Ribozymes useful in the invention and DNA encoding the
ribozymes can be chemically synthesized using methods well known in
the art. The ribozymes can also be prepared from a DNA molecule
(that upon transcription, yields an RNA molecule) operably linked
to an RNA polymerase promoter, for example, the promoter for T7 RNA
polymerase or SP6 RNA polymerase. In a separate embodiment, the DNA
can be inserted into an expression cassette or transcription
cassette. After synthesis, the RNA molecule can be modified by
ligation to a DNA molecule having the ability to stabilize the
ribozyme and make it resistant to RNase.
[1124] As with antisense oligonucleotides, small interfering RNA
and microRNA described herein, catalytic polynucleotides useful in
the invention should be capable of "hybridizing" the target nucleic
acid molecule under "physiological conditions", namely those
conditions within a plant, algal or fungal cell.
Recombinant Vectors
[1125] One embodiment of the present invention includes a
recombinant vector, which comprises at least one polynucleotide
defined herein and is capable of delivering the polynucleotide into
a host cell. Recombinant vectors include expression vectors.
Recombinant vectors contain heterologous polynucleotide sequences,
that is, polynucleotide sequences that are not naturally found
adjacent to a polynucleotide defined herein, that preferably, are
derived from a different species. The vector can be either RNA or
DNA, either prokaryotic or eukaryotic, and typically is a viral
vector, derived from a virus, or a plasmid. Plasmid vectors
typically include additional nucleic acid sequences that provide
for easy selection, amplification, and transformation of the
expression cassette in prokaryotic cells, e.g., pUC-derived
vectors, pSK-derived vectors, pGEM-derived vectors, pSP-derived
vectors, pBS-derived vectors, or binary vectors containing one or
more T-DNA regions. Additional nucleic acid sequences include
origins of replication to provide for autonomous replication of the
vector, selectable marker genes, preferably encoding antibiotic or
herbicide resistance, unique multiple cloning sites providing for
multiple sites to insert nucleic acid sequences or genes encoded in
the nucleic acid construct, and sequences that enhance
transformation of prokaryotic and eukaryotic (especially plant)
cells.
[1126] "Operably linked" as used herein, refers to a functional
relationship between two or more nucleic acid (e.g., DNA) segments.
Typically, it refers to the functional relationship of
transcriptional regulatory element (promoter) to a transcribed
sequence. For example, a promoter is operably linked to a coding
sequence of a polynucleotide defined herein, if it stimulates or
modulates the transcription of the coding sequence in an
appropriate cell. Generally, promoter transcriptional regulatory
elements that are operably linked to a transcribed sequence are
physically contiguous to the transcribed sequence, i.e., they are
cis-acting. However, some transcriptional regulatory elements such
as enhancers, need not be physically contiguous or located in close
proximity to the coding sequences whose transcription they
enhance.
[1127] When there are multiple promoters present, each promoter may
independently be the same or different.
[1128] Recombinant vectors may also contain: (a) one or more
secretory signals which encode signal peptide sequences, to enable
an expressed polypeptide defined herein to be secreted from the
cell that produces the polypeptide, or which provide for
localisation of the expressed polypeptide, for example, for
retention of the polypeptide in the endoplasmic reticulum (ER) in
the cell, or transfer into a plastid, and/or (b) contain fusion
sequences which lead to the expression of nucleic acid molecules as
fusion proteins. Examples of suitable signal segments include any
signal segment capable of directing the secretion or localisation
of a polypeptide defined herein. Preferred signal segments include,
but are not limited to, Nicotiana nectarin signal peptide (U.S.
Pat. No. 5,939,288), tobacco extensin signal, or the soy oleosin
oil body binding protein signal. Recombinant vectors may also
include intervening and/or untranslated sequences surrounding
and/or within the nucleic acid sequence of a polynucleotide defined
herein.
[1129] To facilitate identification of transformants, the
recombinant vector desirably comprises a selectable or screenable
marker gene as, or in addition to, the nucleic acid sequence of a
polynucleotide defined herein. By "marker gene" is meant a gene
that imparts a distinct phenotype to cells expressing the marker
gene and thus, allows such transformed cells to be distinguished
from cells that do not have the marker. A selectable marker gene
confers a trait for which one can "select" based on resistance to a
selective agent (e.g., a herbicide, antibiotic, radiation, heat, or
other treatment damaging to untransformed cells). A screenable
marker gene (or reporter gene) confers a trait that one can
identify through observation or testing, that is, by "screening"
(e.g., .beta.-glucuronidase, luciferase, GFP or other enzyme
activity not present in untransformed cells). The marker gene and
the nucleotide sequence of interest do not have to be linked, since
co-transformation of unlinked genes as for example, described in
U.S. Pat. No. 4,399,216, is also an efficient process in for
example, plant transformation. The actual choice of a marker is not
crucial as long as it is functional (i.e., selective) in
combination with the cells of choice such as a plant cell.
[1130] Examples of bacterial selectable markers are markers that
confer antibiotic resistance such as ampicillin, erythromycin,
chloramphenicol, or tetracycline resistance, preferably kanamycin
resistance. Exemplary selectable markers for selection of plant
transformants include, but are not limited to, a hyg gene which
encodes hygromycin B resistance; a neomycin phosphotransferase
(nptII) gene conferring resistance to kanamycin, paromomycin, G418;
a glutathione-S-transferase gene from rat liver conferring
resistance to glutathione derived herbicides as for example,
described in EP 256223; a glutamine synthetase gene conferring,
upon overexpression, resistance to glutamine synthetase inhibitors
such as phosphinothricin as for example, described in WO 87/05327;
an acetyltransferase gene from Sireptomyces viridochromogenes
conferring resistance to the selective agent phosphinothricin as
for example, described in EP 275957; a gene encoding a
5-enolshikimate-3-phosphate synthase (EPSPS) conferring tolerance
to N-phosphonomethylglycine as for example, described by Hinchee et
al. (1988); a bar gene conferring resistance against bialaphos as
for example, described in WO91/02071; a nitrilase gene such as bxn
from Klebsiella ozaenae which confers resistance to bromoxynil
(Stalker et al., 1988); a dihydrofolate reductase (DHFR) gene
conferring resistance to methotrexate (Thillet et al., 1988); a
mutant acetolactate synthase gene (ALS) which confers resistance to
imidazolinone, sulfonylurea, or other ALS-inhibiting chemicals (EP
154,204); a mutated anthranilate synthase gene that confers
resistance to 5-methyl tryptophan; or a dalapon dehalogenase gene
that confers resistance to the herbicide.
[1131] Preferred screenable markers include, but are not limited
to, a uidA gene encoding a .beta.-glucuronidase (GUS) enzyme for
which various chromogenic substrates are known; a
.beta.-galactosidase gene encoding an enzyme for which chromogenic
substrates are known; an aequorin gene (Prasher et al., 1985) which
may be employed in calcium-sensitive bioluminescence detection; a
green fluorescent protein gene (Niedz et al., 1995) or derivatives
thereof; or a luciferase (luc) gene (Ow et al., 1986) which allows
for bioluminescence detection. By "reporter molecule" it is meant a
molecule that, by its chemical nature, provides an analytically
identifiable signal that facilitates determination of promoter
activity by reference to protein product.
[1132] Preferably, the recombinant vector is stably incorporated
into the genome of the cell such as the plant cell. Accordingly,
the recombinant vector may comprise appropriate elements which
allow the vector to be incorporated into the genome, or into a
chromosome of the cell.
Expression Vector
[1133] As used herein, an "expression vector" is a DNA or RNA
vector that is capable of transforming a host cell and of effecting
expression of one or more specified polynucleotides. Preferably,
the expression vector is also capable of replicating within the
host cell. Expression vectors can be either prokaryotic or
eukaryotic, and are typically viruses or plasmids. Expression
vectors of the present invention include any vectors that function
(i.e., direct gene expression) in host cells of the present
invention, including in bacterial, fungal, endoparasite, arthropod,
animal, algal, and plant cells. Particularly preferred expression
vectors of the present invention can direct gene expression in
yeast, algae and/or plant cells.
[1134] Expression vectors of the present invention contain
regulatory sequences such as transcription control sequences,
translation control sequences, origins of replication, and other
regulatory sequences that are compatible with the host cell and
that control the expression of polynucleotides of the present
invention. In particular, expression vectors of the present
invention include transcription control sequences. Transcription
control sequences are sequences which control the initiation,
elongation, and termination of transcription. Particularly
important transcription control sequences are those which control
transcription initiation such as promoter, enhancer, operator and
repressor sequences. Suitable transcription control sequences
include any transcription control sequence that can function in at
least one of the recombinant cells of the present invention. The
choice of the regulatory sequences used depends on the target
organism such as a plant and/or target organ or tissue of interest.
Such regulatory sequences may be obtained from any eukaryotic
organism such as plants or plant viruses, or may be chemically
synthesized. A variety of such transcription control sequences are
known to those skilled in the art. Particularly preferred
transcription control sequences are promoters active in directing
transcription in plants, either constitutively or stage and/or
tissue specific, depending on the use of the plant or part(s)
thereof.
[1135] A number of vectors suitable for stable transfection of
plant cells or for the establishment of transgenic plants have been
described in for example, Pouwels et al., Cloning Vectors: A
Laboratory Manual, 1985, supp. 1987, Weissbach and Weissbach,
Methods for Plant Molecular Biology, Academic Press, 1989, and
Gelvin et at, Plant Molecular Biology Manual, Kluwer Academic
Publishers, 1990. Typically, plant expression vectors include for
example, one or more cloned plant genes under the transcriptional
control of 5' and 3' regulatory sequences and a dominant selectable
marker. Such plant expression vectors also can contain a promoter
regulatory region (e.g., a regulatory region controlling inducible
or constitutive, environmentally- or developmentally-regulated, or
cell- or tissue-specific expression), a transcription initiation
start site, a ribosome binding site, an RNA processing signal, a
transcription termination site, and/or a polyadenylation
signal.
[1136] A number of constitutive promoters that are active in plant
cells have been described. Suitable promoters for constitutive
expression in plants include, but are not limited to, the
cauliflower mosaic virus (CaMV) 35S promoter, the Figwort mosaic
virus (FMV) 35S, the sugarcane bacilliform virus promoter, the
commelina yellow mottle virus promoter, the light-inducible
promoter from the small subunit of the ribulose-1,5-bis-phosphate
carboxylase, the rice cytosolic triosephosphate isomerase promoter,
the adenine phosphoribosyltransferase promoter of Arabidopsis, the
rice actin 1 gene promoter, the mannopine synthase and octopine
synthase promoters, the Adh promoter, the sucrose synthase
promoter, the R gene complex promoter, and the chlorophyll
.alpha./.beta. binding protein gene promoter. These promoters have
been used to create DNA vectors that have been expressed in plants,
see for example, WO 84/02913. All of these promoters have been used
to create various types of plant-expressible recombinant DNA
vectors.
[1137] For the purpose of expression in source tissues of the plant
such as the leaf, seed, root or stem, it is preferred that the
promoters utilized in the present invention have relatively high
expression in these specific tissues. For this purpose, one may
choose from a number of promoters for genes with tissue- or
cell-specific, or -enhanced expression. Examples of such promoters
reported in the literature include, the chloroplast glutamine
synthetase GS2 promoter from pea, the chloroplast
fructose-1,6-biphosphatase promoter from wheat, the nuclear
photosynthetic ST-LS1 promoter from potato, the serine/threonine
kinase promoter and the glucoamylase (CHS) promoter from
Arabidopsis thaliana. Also reported to be active in
photosynthetically active tissues are the ribulose-1,5-bisphosphate
carboxylase promoter from eastern larch (Larix laricina), the
promoter for the Cab gene, Cab6, from pine, the promoter for the
Cab-1 gene from wheat, the promoter for the Cab-1 gene from
spinach, the promoter for the Cab 1R gene from rice, the pyruvate,
orthophosphate dikinase (PPDK) promoter from Zea mays, the promoter
for the tobacco Lhcb1*2 gene, the Arabidopsis thaliana Suc2
sucrose-H.sup.30 symporter promoter, and the promoter for the
thylakoid membrane protein genes from spinach (PsaD, PsaF, PsaE,
PC, FNR, AtpC, AtpD, Cab, RbcS). Other promoters for the
chlorophyll .alpha./.beta.-binding proteins may also be utilized in
the present invention such as the promoters for LhcB gene and PsbP
gene from white mustard (Sinapis alba).
[1138] A variety of plant gene promoters that are regulated in
response to environmental, hormonal, chemical, and/or developmental
signals, also can be used for expression of RNA-binding protein
genes in plant cells, including promoters regulated by (1) heat,
(2) light (e.g., pea RbcS-3A promoter, maize RbcS promoter), (3)
hormones such as abscisic acid, (4) wounding (e.g., WunI), or (5)
chemicals such as methyl jasmonate, salicylic acid, steroid
hormones, alcohol, Safeners (WO 97/06269), or it may also be
advantageous to employ (6) organ-specific promoters.
[1139] As used herein, the term "plant storage organ specific
promoter" refers to a promoter that preferentially, when compared
to other plant tissues, directs gene transcription in a storage
organ of a plant. Preferably, the promoter only directs expression
of a gene of interest in the storage organ, and/or expression of
the gene of interest in other parts of the plant such as leaves is
not detectable by Northern blot analysis and/or RT-PCR. Typically,
the promoter drives expression of genes during growth and
development of the storage organ, in particular during the phase of
synthesis and accumulation of storage compounds in the storage
organ. Such promoters may drive gene expression in the entire plant
storage organ or only part thereof such as the seedcoat, embryo or
cotyledon(s) in seeds of dicotyledonous plants or the endosperm or
aleurone layer of seeds of monocotyledonous plants.
[1140] For the purpose of expression in sink tissues of the plant
such as the tuber of the potato plant, the fruit of tomato, or the
seed of soybean, canola, cotton, Zea mays, wheat, rice, and barley,
it is preferred that the promoters utilized in the present
invention have relatively high expression in these specific
tissues. A number of promoters for genes with tuber-specific or
-enhanced expression are known, including the class I patatin
promoter, the promoter for the potato tuber ADPGPP genes, both the
large and small subunits, the sucrose synthase promoter, the
promoter for the major tuber proteins, including the 22 kD protein
complexes and proteinase inhibitors, the promoter for the granule
bound starch synthase gene (GBSS), and other class I and II
patatins promoters. Other promoters can also be used to express a
protein in specific tissues such as seeds or fruits. The promoter
for .beta.-conglycinin or other seed-specific promoters such as the
napin, zein, linin and phaseolin promoters, can be used. Root
specific promoters may also be used. An example of such a promoter
is the promoter for the acid chitinase gene. Expression in root
tissue could also be accomplished by utilizing the root specific
subdomains of the CaMV 35S promoter that have been identified.
[1141] In a particularly preferred embodiment, the promoter directs
expression in tissues and organs in which lipid biosynthesis take
place. Such promoters may act in seed development at a suitable
time for modifying lipid composition in seeds.
[1142] In an embodiment, the promoter is a plant storage organ
specific promoter. In one embodiment, the plant storage organ
specific promoter is a seed specific promoter. In a more preferred
embodiment, the promoter preferentially directs expression in the
cotyledons of a dicotyledonous plant or in the endosperm of a
monocotyledonous plant, relative to expression in the embryo of the
seed or relative to other organs in the plant such as leaves.
Preferred promoters for seed-specific expression include: 1)
promoters from genes encoding enzymes involved in lipid
biosynthesis and accumulation in seeds such as desaturases and
elongases, 2) promoters from genes encoding seed storage proteins,
and 3) promoters from genes encoding enzymes involved in
carbohydrate biosynthesis and accumulation in seeds. Seed specific
prommoters which are suitable are, the oilseed rape napin gene
promoter (U.S. Pat. No. 5,608,152), the Viciafaba USP promoter
(Baumlein et al., 1991), the Arabidopsis oleosin promoter (WO
98/45461), the Phaseolus vulgaris phaseolin promoter (U.S. Pat. No.
5,504,200), the Brassica Bce4 promoter (WO 91/13980), or the
legumin B4 promoter (Baumlein et al., 1992), and promoters which
lead to the seed-specific expression in monocots such as maize,
barley, wheat, rye, rice and the like. Notable promoters which are
suitable are the barley lpt2 or Ipt1 gene promoter (WO 95/15389 and
WO 95/23230), or the promoters described in WO 99/16890 (promoters
from the barley hordein gene, the rice glutelin gene, the rice
oryzin gene, the rice prolamin gene, the wheat gliadin gene, the
wheat glutelin gene, the maize zein gene, the oat glutelin gene,
the sorghum kasirin gene, the rye secalin gene). Other promoters
include those described by Broun et al. (1998), Potenza et al.
(2004), US 20070192902 and US 20030159173. In an embodiment, the
seed specific promoter is preferentially expressed in defined parts
of the seed such as the cotyledon(s) or the endosperm. Examples of
cotyledon specific promoters include, but are not limited to, the
FP1 promoter (Ellerstrom et al., 1996), the pea legumin promoter
(Perrin et al., 2000), and the bean phytohemagglutnin promoter
(Perrin et al., 2000). Examples of endospernn specific promoters
include, but are not limited to, the maize zein-1 promoter
(Chikwamba et al., 2003), the rice glutelin-1 promoter (Yang et
al., 2003), the barley D-hordein promoter (Horvath et al., 2000)
and wheat HMW glutenin promoters (Alvarez et al., 2000). In a
further embodiment, the seed specific promoter is not expressed, or
is only expressed at a low level, in the embryo and/or after the
seed germinates.
[1143] In another embodiment, the plant storage organ specific
promoter is a tuber specific promoter. Examples include, but are
not limited to, the potato patatin B33, PAT21 and GBSS promoters,
as well as the sweet potato sporamin promoter (for review, see
Potenza et al., 2004). In a preferred embodiment, the promoter
directs expression preferentially in the pith of the tuber,
relative to the outer layers (skin, bark) or the embryo of the
tuber.
[1144] In another embodiment, the plant storage organ specific
promoter is a fruit specific promoter. Examples include, but are
not limited to, the tomato polygalacturonase, E8 and Pds promoters,
as well as the apple ACC oxidase promoter (for review, see Potenza
et al., 2004). In a preferred embodiment, the promoter
preferentially directs expression in the edible parts of the fruit,
for example the pith of the fruit, relative to the skin of the
fruit or the seeds within the fruit.
[1145] In an embodiment, the inducible promoter is the Aspergillus
nidulans alc system. Examples of inducible expression systems which
can be used instead of the Aspergillus nidulans alc system are
described in a review by Padidam (2003) and Corrado and Karali
(2009). These include tetracycline repressor (TetR)-based and
tetracycline inducible systems (Gatz, 1997), tetracycline
repressor-based and tetracycline-inactivatable systems (Weinmann et
al., 1994), glucocorticoid receptor-based (Picard, 1994), estrogen
receptor-based and other steroid-inducible systems systems (Bruce
et al., 2000), glucocorticoid receptor-, tetracycline
repressor-based dual control systems (Bohner et al., 1999),
ecdysone receptor-based, insecticide-inducible systems (Martinez et
al., 1999, Padidam et al., 2003, Unger et al, 2002, Riddiford et
al., 2000, Dhadialla et al., 1998, Martinez and Jepson, 1999),
AlcR-based, ethanol-inducible systems (Felenbok, 1991) and
ACEI-based, copper-inducible systems (Mett et al., 1993).
[1146] In another embodiment, the inducible promoter is a safener
inducible promoter such as, for example, the maize ln2-1 or ln2-2
promoter (Hershey and Stoner, 1991), the safener inducible promoter
is the maize GST-27 promoter (Jepson et al., 1994), or the soybean
GH2/4 promoter (Ulmasov et al., 1995).
[1147] Safeners are a group of structurally diverse chemicals used
to increase the plant's tolerance to the toxic effects of an
herbicidal compound. Examples of these compounds include naphthalic
anhydride and N,N-diallyl-2,2-dichloroacetamide (DDCA), which
protect maize and sorghum against thiocarbamate herbicides;
cyometrinil, which protects sorghum against metochlor,
triapenthenol, which protects soybeans against metribuzin; and
substituted benzenesulfonamides, which improve the tolerance of
several cereal crop species to sulfonylurea herbicides.
[1148] In another embodiment, the inducible promoter is a
senescence inducible promoter such as, for example,
senescence-inducible promoter SAG (senescence associated gene) 12
and SAG 13 from Arabidopsis (Gan, 1995; Gan and Amasino, 1995) and
LSC54 from Brassica napus (Buchanan-Wollaston, 1994).
[1149] For expression in vegetative tissue leaf-specific promoters,
such as the ribulose biphosphate carboxylase (RBCS) promoters, can
be used. For example, the tomato RBCS1, RBCS2 and RBCS3A genes are
expressed in leaves and light grown seedlings (Meier et al., 1997).
A ribulose bisphosphate carboxylase promoters expressed almost
exclusively in mesophyll cells in leaf blades and leaf sheaths at
high levels, described by Matsuoka et al. (1994), can be used.
Another leaf-specific promoter is the light harvesting chlorophyll
a/b binding protein gene promoter (see, Shiina et al., 1997). The
Arabidopsis thaliana myb-related gene promoter (Atmyb5) described
by Li et al. (1996), is leaf-specific. The Atmyb5 promoter is
expressed in developing leaf trichomes, stipules, and epidermal
cells on the margins of young rosette and cauline leaves, and in
immature seeds. A leaf promoter identified in maize by Busk et al.
(1997), can also be used.
[1150] In some instances, for example when LEC2 or BBM is
recombinantly expressed, it may be desirable that the transgene is
not expressed at high levels. An example of a promoter which can be
used in such circumstances is a truncated napin A promoter which
retains the seed-specific expression pattern but with a reduced
expression level (Tan et al., 2011).
[1151] The 5' non-tanslated leader sequence can be derived from the
promoter selected to express the heterologous gene sequence of the
polynucleotide of the present invention, or may be heterologous
with respect to the coding region of the enzyme to be produced, and
can be specifically modified if desired so as to increase
translation of mRNA. For a review of optimizing expression of
transgenes, see Koziel et al. (1996). The 5' non-translated regions
can also be obtained from plant viral RNAs (Tobacco mosaic virus,
Tobacco etch virus, Maize dwarf mosaic virus, Alfalfa mosaic virus,
among others) from suitable eukaryotic genes, plant genes (wheat
and maize chlorophyll a/b binding protein gene leader), or from a
synthetic gene sequence. The present invention is not limited to
constructs wherein the non-translated region is derived from the 5'
non-translated sequence that accompanies the promoter sequence. The
leader sequence could also be derived from an unrelated promoter or
coding sequence. Leader sequences useful in context of the present
invention comprise the maize Hsp70 leader (U.S. Pat. Nos. 5,362,865
and 5,859,347), and the TMV omega element.
[1152] The termination of transcription is accomplished by a 3'
non-translated DNA sequence operably linked in the expression
vector to the polynucleotide of interest. The 3' non-translated
region of a recombinant DNA molecule contains a polyadenylation
signal that functions in plants to cause the addition of adenylate
nucleotides to the 3' end of the RNA. The 3' non-translated region
can be obtained from various genes that are expressed in plant
cells. The nopaline synthase 3' untranslated region, the 3'
untranslated region from pea small subunit Rubisco gene, the 3'
untranslated region from soybean 7S seed storage protein gene are
commonly used in this capacity. The 3' transcribed, non-translated
regions containing the polyadenylate signal of Agrobacterium
tumor-inducing (Ti) plasmid genes are also suitable.
[1153] Recombinant DNA technologies can be used to improve
expression of a transformed polynucleotide by manipulating for
example, the number of copies of the polynucleotide within a host
cell, the efficiency with which those polynucleotide are
transcribed, the efficiency with which the resultant transcripts
are translated, and the efficiency of post-translational
modifications. Recombinant techniques useful for increasing the
expression of polynucleotides defined herein include, but are not
limited to, operatively linking the polynucleotide to a high-copy
number plasmid, integration of the polynucleotide molecule into one
or more host cell chromosomes, addition of vector stability
sequences to the plasmid, substitutions or modifications of
transcription control signals (e.g., promoters, operators,
enhancers), substitutions or modifications of translational control
signals (e.g., ribosome binding sites, Shine-Dalgarno sequences),
modification of the polynucleotide to correspond to the codon usage
of the host cell, and the deletion of sequences that destabilize
transcripts.
Transfer Nucleic Acids
[1154] Transfer nucleic acids can be used to deliver an exogenous
polynucleotide to a cell and comprise one, preferably two, border
sequences and a polynucleotide of interest. The transfer nucleic
acid may or may not encode a selectable marker. Preferably, the
transfer nucleic acid forms part of a binary vector in a bacterium,
where the binary vector further comprises elements which allow
replication of the vector in the bacterium, selection, or
maintenance of bacterial cells containing the binary vector. Upon
transfer to a eukaryotic cell, the transfer nucleic acid component
of the binary vector is capable of integration into the genome of
the eukaryotic cell.
[1155] As used herein, the term "extrachromosomal transfer nucleic
acid" refers to a nucleic acid molecule that is capable of being
transferred from a bacterium such as Agrobacterium sp., to a
eukaryotic cell such as a plant leaf cell. An extrachromosomal
transfer nucleic acid is a genetic element that is well-known as an
element capable of being transferred, with the subsequent
integration of a nucleotide sequence contained within its borders
into the genome of the recipient cell. In this respect, a transfer
nucleic acid is flanked, typically, by two "border" sequences,
although in some instances a single border at one end can be used
and the second end of the transferred nucleic acid is generated
randomly in the transfer process. A polynucleotide of interest is
typically positioned between the left border-like sequence and the
right border-like sequence of a transfer nucleic acid. The
polynucleotide contained within the transfer nucleic acid may be
operably linked to a variety of different promoter and terminator
regulatory elements that facilitate its expression, that is,
transcription and/or translation of the polynucleotide. Transfer
DNAs (T-DNAs) from Agrobacterium sp. such as Agrobacterium
tumefaciens or Agrobacterium rhizogenes, and man made
variants/mutants thereof are probably the best characterized
examples of transfer nucleic acids. Another example is P-DNA
("plant-DNA") which comprises T-DNA border-like sequences from
plants.
[1156] As used herein, "T-DNA" refers to for example, T-DNA of an
Agrobacterium tumefaciens Ti plasmid or from an Agrobacterium
rhizogenes Ri plasmid, or man made variants thereof which function
as T-DNA. The T-DNA may comprise an entire T-DNA including both
right and left border sequences, but need only comprise the minimal
sequences required in cis for transfer, that is, the right and
T-DNA border sequence. The T-DNAs of the invention have inserted
into them, anywhere between the right and left border sequences (if
present), the polynucleotide of interest flanked by target sites
for a site-specific recombinase. The sequences encoding factors
required in trans for transfer of the T-DNA into a plant cell such
as vir genes, may be inserted into the T-DNA, or may be present on
the same replicon as the T-DNA, or preferably are in trans on a
compatible replicon in the Agrobacterium host. Such "binary vector
systems" are well known in the art.
[1157] As used herein, "P-DNA" refers to a transfer nucleic acid
isolated from a plant genome, or man made variants/mutants thereof,
and comprises at each end, or at only one end, a T-DNA border-like
sequence. The border-like sequence preferably shares at least 50%,
at least 60%, at least 70%, at least 75%, at least 80%, at least
90% or at least 95%, but less than 100% sequence identity, with a
T-DNA border sequence from an Agrobacterium sp. such as
Agrobacterium tumefaciens or Agrobacterium rhizogenes. Thus, P-DNAs
can be used instead of T-DNAs to transfer a nucleotide sequence
contained within the P-DNA from, for example Agrobacterium, to
another cell. The P-DNA, before insertion of the exogenous
polynucleotide which is to be transferred, may be modified to
facilitate cloning and should preferably not encode any proteins.
The P-DNA is characterized in that it contains, at least a right
border sequence and preferably also a left border sequence.
[1158] As used herein, a "border" sequence of a transfer nucleic
acid can be isolated from a selected organism such as a plant or
bacterium, or be a man made variant/mutant thereof. The border
sequence promotes and facilitates the transfer of the
polynucleotide to which it is linked and may facilitate its
integration in the recipient cell genome. In an embodiment, a
border-sequence is between 5-100 base pairs (bp) in length, 10-80
bp in length, 15-75 bp in length, 15-60 bp in length, 15-50 bp in
length, 15-40 bp in length, 15-30 bp in length, 16-30 bp in length,
20-30 bp in length, 21-30 bp in length, 22-30 bp in length, 23-30
bp in length, 24-30 bp in length, 25-30 bp in length, or 26-30 bp
in length. Border sequences from T-DNA from Agrobacterium sp. are
well known in the art and include those described in Lacroix et al.
(2008), Tzfira and Citovsky (2006) and Glevin (2003).
[1159] Whilst traditionally only Agrobacterium sp. have been used
to transfer genes to plants cells, there are now a large number of
systems which have been identified/developed which act in a similar
manner to Agrobacterium sp. Several non-Agrobacterium species have
recently been genetically modified to be competent for gene
transfer (Chung et al., 2006; Broothaerts et al., 2005). These
include Rhizobium sp. NGR234, Sinorhizobium meliloti and
Mezorhizobium loti. The bacteria are made competent for gene
transfer by providing the bacteria with the machinery needed for
the transformation process, that is, a set of virulence genes
encoded by an Agrobacterium Ti-plasmid and the T-DNA segment
residing on a separate, small binary plasmid. Bacteria engineered
in this way are capable of transforming different plant tissues
(leaf disks, calli and oval tissue), monocots or dicots, and
various different plant species (e.g., tobacco, rice).
[1160] Direct transfer of eukaryotic expression plasmids from
bacteria to eukaryotic hosts was first achieved several decades ago
by the fusion of mammalian cells and protoplasts of
plasmid-carrying Escherichia coli (Schaffner, 1980). Since then,
the number of bacteria capable of delivering genes into mammalian
cells has steadily increased (Weiss, 2003), being discovered by
four groups independently (Sizemore et al. 1995; Courvalin et al.,
1995; Powell et al., 1996; Darji et al., 1997).
[1161] Attenuated Shigella flexneri, Salmonella typhimurium or E.
coli that had been rendered invasive by the virulence plasmid
(pWR100) of S. flexneri have been shown to be able to transfer
expression plasmids after invasion of host cells and intracellular
death due to metabolic attenuation. Mucosal application, either
nasally or orally, of such recombinant Shigella or Salmonella
induced immune responses against the antigen that was encoded by
the expression plasmids. In the meantime, the list of bacteria that
was shown to be able to transfer expression plasmids to mammalian
host cells in vitro and in vivo has been more then doubled and has
been documented for S. typhi, S. choleraesuis, Listeria
monocytogenes, Yersinia pseudotuberculosis, and Y. enterocolitica
(Fennelly et al., 1999; Shiau et al., 2001; Dietrich et al., 1998;
Hense et al., 2001; Al-Mariri et al., 2002).
[1162] In general, it could be assumed that all bacteria that are
able to enter the cytosol of the host cell (like S. flexneri or L.
monocytogenes) and lyse within this cellular compartment, should be
able to transfer DNA. This is known as `abortive` or `suicidal`
invasion as the bacteria have to lyse for the DNA transfer to occur
(Grillot-Courvalin et al., 1999). In addition, even many of the
bacteria that remain in the phagocytic vacuole (like S.
typhimurium) may also be able to do so. Thus, recombinant
laboratory strains of E. coli that have been engineered to be
invasive but are unable of phagosomal escape, could deliver their
plasmid load to the nucleus of the infected mammalian cell
nevertheless (Grillot-Courvalin et al., 1998). Furthermore,
Agrobacterium tumefaciens has recently also been shown to introduce
transgenes into mammalian cells (Kunik et al., 2001).
[1163] As used herein, the terms "transfection", "transformation"
and variations thereof are generally used interchangeably.
"Transfected" or "transformed" cells may have been manipulated to
introduce the polynucleotide(s) of interest, or may be progeny
cells derived therefrom.
Recombinant Cells
[1164] The invention also provides a recombinant cell, for example,
a recombinant plant cell, which is a host cell transformed with one
or more polynucleotides or vectors defined herein, or combination
thereof. The term "recombinant cell" is used interchangeably with
the term "transgenic cell" herein. Suitable cells of the invention
include any cell that can be transformed with a polynucleotide or
recombinant vector of the invention, encoding for example, a
polypeptide or enzyme described herein. The cell is preferably a
cell which is thereby capable of being used for producing lipid.
The recombinant cell may be a cell in culture, a cell in vitro, or
in an organism such as for example, a plant, or in an organ such
as, for example, a seed or a leaf. Preferably, the cell is in a
plant, more preferably in the seed of a plant. In one embodiment,
the recombinant cell is a non-human cell.
[1165] Host cells into which the polynucleotide(s) are introduced
can be either untransformed cells or cells that are already
transformed with at least one nucleic acid. Such nucleic acids may
be related to lipid synthesis, or unrelated. Host cells of the
present invention either can be endogenously (i.e., naturally)
capable of producing polypeptide(s) defined herein, in which case
the recombinant cell derived therefrom has an enhanced capability
of producing the polypeptide(s), or can be capable of producing
said polypeptide(s) only after being transformed with at least one
polynucleotide of the invention. In an embodiment, a recombinant
cell of the invention has an enhanced capacity to produce non-polar
lipid.
[1166] Host cells of the present invention can be any cell capable
of producing at least one protein described herein, and include
bacterial, fungal (including yeast), parasite, arthropod, animal,
algal, and plant cells. The cells may be prokaryotic or eukaryotic.
Preferred host cells are yeast, algal and plant cells. In a
preferred embodiment, the plant cell is a seed cell, in particular,
a cell in a cotyledon or endosperm of a seed. In one embodiment,
the cell is an animal cell. The animal cell may be of any type of
animal such as, for example, a non-human animal cell, a non-human
vertebrate cell, a non-human mammalian cell, or cells of aquatic
animals such as fish or crustacea, invertebrates, insects, etc. Non
limiting examples of arthropod cells include insect cells such as
Spodoptera frugiperda (Sf) cells, for example, Sf9, Sf21,
Trichoplusia ni cells, and Drosophila S2 cells. An example of a
bacterial cell useful as a host cell of the present invention is
Synechococcus spp. (also known as Synechocystis spp.), for example
Synechococcus elongatus. Examples of algal cells useful as host
cells of the present invention include, for example, Chlamydomonas
sp. (for example, Chlamydomonas reinhardtii), Dunaliella sp.,
Haematococcus sp., Chlorella sp., Thraustochytrium sp.,
Schizochyrium sp., and Volvox sp.
[1167] Host cells for expression of the instant nucleic acids may
include microbial hosts that grow on a variety of feedstocks,
including simple or complex carbohydrates, organic acids and
alcohols and/or hydrocarbons over a wide range of temperature and
pH values. Preferred microbial hosts are oleaginous organisms that
are naturally capable of non-polar lipid synthesis.
[1168] The host cells may be of an organism suitable for a
fermentation process, such as, for example, Yarrowia lipolytica or
other yeasts.
Transgenic Plants
[1169] The invention also provides a plant comprising an exogenous
polynucleotide or polypeptide of the invention, a cell of the
invention, a vector of the invention, or a combination thereof. The
term "plant" refers to whole plants, whilst the term "part thereof"
refers to plant organs (e.g., leaves, stems, roots, flowers,
fruit), single cells (e.g., pollen), seed, seed parts such as an
embryo, endosperm, scutellum or seed coat, plant tissue such as
vascular tissue, plant cells and progeny of the same. As used
herein, plant parts comprise plant cells.
[1170] As used herein, the term "plant" is used in it broadest
sense. It includes, but is not limited to, any species of grass,
ornamental or decorative plant, crop or cereal (e.g., oilseed,
maize, soybean), fodder or forage, fruit or vegetable plant, herb
plant, woody plant, flower plant, or tree. It is not meant to limit
a plant to any particular structure. It also refers to a
unicellular plant (e.g., microalga). The term "part thereof" in
reference to a plant refers to a plant cell and progeny of same, a
plurality of plant cells that are largely differentiated into a
colony (e.g., volvox), a structure that is present at any stage of
a plant's development, or a plant tissue. Such structures include,
but are not limited to, leaves, stems, flowers, fruits, nuts,
roots, seed, seed coat, embryos. The term "plant tissue" includes
differentiated and undifferentiated tissues of plants including
those present in leaves, stems, flowers, fruits, nuts, roots, seed,
for example, embryonic tissue, endosperm, dermal tissue (e.g.,
epidermis, periderm), vascular tissue (e.g., xylem, phloem), or
ground tissue (comprising parenchyma, collenchyma, and/or
sclerenchyma cells), as well as cells in culture (e.g., single
cells, protoplasts, callus, embryos, etc.). Plant tissue may be in
planta, in organ culture, tissue culture, or cell culture.
[1171] A "transgenic plant", "genetically modified plant" or
variations thereof refers to a plant that contains a transgene not
found in a wild-type plant of the same species, variety or
cultivar. Transgenic plants as defined in the context of the
present invention include plants and their progeny which have been
genetically modified using recombinant techniques to cause
production of at least one polypeptide defined herein in the
desired plant or part thereof. Transgenic plant parts has a
corresponding meaning.
[1172] The terms "seed" and "grain" are used interchangeably
herein. "Grain" refers to mature grain such as harvested grain or
grain which is still on a plant but ready for harvesting, but can
also refer to grain after imbibition or germination, according to
the context. Mature grain commonly has a moisture content of less
than about 18-20%. In a preferred embodiment, the moisture content
of the grain is at a level which is generally regarded as safe for
storage, preferably between 5% and 15%, between 6% and 8%, between
8% and 10%, or between 12% and 15%. "Developing seed" as used
herein refers to a seed prior to maturity, typically found in the
reproductive structures of the plant after fertilisation or
anthesis, but can also refer to such seeds prior to maturity which
are isolated from a plant. Mature seed commonly has a moisture
content of less than about 18-20%. In a preferred embodiment, the
moisture content of the seed is at a level which is generally
regarded as safe for storage, preferably between 5% and 15%,
between 6% and 8%, between 8% and 10%, or between 12% and 15%.
[1173] As used herein, the term "plant storage organ" refers to a
part of a plant specialized to store energy in the form of for
example, proteins, carbohydrates, lipid. Examples of plant storage
organs are seed, fruit, tuberous roots, and tubers. A preferred
plant storage organ of the invention is seed.
[1174] As used herein, the term "phenotypically normal" refers to a
genetically modified plant or part thereof, particularly a storage
organ such as a seed, tuber or fruit of the invention not having a
significantly reduced ability to grow and reproduce when compared
to an unmodified plant or plant thereof. In an embodiment, the
genetically modified plant or part thereof which is phenotypically
normal comprises a recombinant polynucleotide encoding a silencing
suppressor operably linked to a plant storage organ specific
promoter and has an ability to grow or reproduce which is
essentially the same as a corresponding plant or part thereof not
comprising said polynucleotide. Preferably, the biomass, growth
rate, germination rate, storage organ size, seed size and/or the
number of viable seeds produced is not less than 90.degree. % of
that of a plant lacking said recombinant polynucleotide when grown
under identical conditions. This term does not encompass features
of the plant which may be different to the wild-type plant but
which do not effect the usefulness of the plant for commercial
purposes such as, for example, a ballerina phenotype of seedling
leaves.
[1175] Plants provided by or contemplated for use in the practice
of the present invention include both monocotyledons and
dicotyledons. In preferred embodiments, the plants of the present
invention are crop plants (for example, cereals and pulses, maize,
wheat, potatoes, tapioca, rice, sorghum, millet, cassava, barley,
or pea), or other legumes. The plants may be grown for production
of edible roots, tubers, leaves, stems, flowers or fruit. The
plants may be vegetable or ornamental plants. The plants of the
invention may be: Acrocomia aculeata (macauba palm), Arabidopsis
thaliana, Aracinis hypogaea (peanut), Astrocaryum murumuru
(murumuru), Astrocaryum vulgare (tucuma), Attalea geraensis
(Indaia-rateiro), Attalea humilis (American oil palm), Attalea
oleifera (andaia), Attalea phalerata (uricuri), Attalea speciosa
(babassu), Avena saliva (oats), Beta vulgaris (sugar beet),
Brassica sp. such as Brassica carinata, Brassica juncea, Brassica
napobrassica, Brassica napus (canola), Camelina saliva (false
flax), Cannabis saliva (hemp), Carthamus tinclorius (safflower),
Caryocar brasiliense (pequi), Cocos nucifera (Coconut), Crambe
abyssinica (Abyssinian kale), Cucumis melo (melon), Elaeis
guineensis (African palm), Glycine max (soybean), Gossypium
hirsutum (cotton), Helianthus sp. such as Helianthus annuus
(sunflower), Hordeum vulgare (barley), Jatropha curcas (physic
nut), Joannesia princeps (arara nut-tree), Lemna sp. (duckweed)
such as Lemna aequinoctialis, Lemna disperma, Lemna ecuadoriensis,
Lemna gibba (swollen duckweed), Lemna japonica, Lemna minor, Lemna
minuta, Lemna obscura, Lemna paucicostata, Lemna perpusilla, Lemna
lenera, Lemna trisulca, Lemna turionifera, Lemna valdiviana, Lemna
yungensis, Licania rigida (oiticica), Linum usitatissimum (flax),
Lupinus angustifolius (lupin), Mauritia flexuosa (buriti palm),
Maximiliana maripa (inaja palm), Miscanthus sp. such as Miscanthus
x giganteus and Miscanthus sinensis, Nicotiana sp. (tabacco) such
as Nicotiana tabacum or Nicotiana benthamiana, Oenocarpus bacaba
(bacaba-do-azeite), Oenocarpus bataua (pataua), Oenocarpus
distichus (bacaba-de-leque), Oryza sp. (rice) such as Oryza sativa
and Oryza glaberrima, Panicum virgatum (switchgrass), Paraqueiba
paraensis (mari), Persea amencana (avocado), Pongamia pinnata
(Indian beech), Populus trichocarpa, Ricinus communis (castor),
Saccharum sp. (sugarcane), Sesamum indicum (sesame), Solanum
tuberosum (potato), Sorghum sp. such as Sorghum bicolor, Sorghum
vulgare, Theobroma grandiforum (cupuassu), Trifolium sp.,
Trithrinax brasiliensis (Brazilian needle palm), Triticum sp.
(wheat) such as Triticum aestivum, Zea mays (corn), alfalfa
(Medicago saliva), rye (Secale cerale), sweet potato (Lopmoea
batatus), cassava (Manihot esculenta), coffee (Cofea spp.),
pineapple (Anana comosus), citris tree (Citrus spp.), cocoa
(Theobroma cacao), tea (Camellia senensis), banana (Musa spp.),
avocado (Persea americana), fig (Ficus casica), guava (Psidium
guajava), mango (Mangifer indica), olive (Olea europaea), papaya
(Carica papaya), cashew (Anacardium occidentale), macadamia
(Macadamia intergrifolia) and almond (Prunus amygdalus).
[1176] Other preferred plants include C4 grasses such as, in
addition to those mentioned above, Andropogon gerardi, Bouteloua
curtipendula, B. gracilis, Buchloe dactyloides, Schizachyrium
scoparium, Sorghastrum nutans, Sporobolus cryptandrus; C3 grasses
such as Elymus canadensis, the legumes Lespedeza capitata and
Petalostemum villosum, the forb Aster azureus; and woody plants
such as Quercus ellipsoidalis and Q. macrocarpa. Other preferred
plants include C3 grasses.
[1177] In a preferred embodiment, the plant is an angiosperm.
[1178] In an embodiment, the plant is an oilseed plant, preferably
an oilseed crop plant. As used herein, an "oilseed plant" is a
plant species used for the commercial production of lipid from the
seeds of the plant. The oilseed plant may be, for example, oil-seed
rape (such as canola), maize, sunflower, safflower, soybean,
sorghum, flax (linseed) or sugar beet. Furthermore, the oilseed
plant may be other Brassicas, cotton, peanut, poppy, rutabaga,
mustard, castor bean, sesame, safflower, or nut producing plants.
The plant may produce high levels of lipid in its fruit such as
olive, oil palm or coconut. Horticultural plants to which the
present invention may be applied are lettuce, endive, or vegetable
Brassicas including cabbage, broccoli, or cauliflower. The present
invention may be applied in tobacco, cucurbits, carrot, strawberry,
tomato, or pepper.
[1179] In a preferred embodiment, the transgenic plant is
homozygous for each and every gene that has been introduced
(transgene) so that its progeny do not segregate for the desired
phenotype. The transgenic plant may also be heterozygous for the
introduced transgene(s), preferably uniformly heterozygous for the
transgene such as for example, in F1 progeny which have been grown
from hybrid seed. Such plants may provide advantages such as hybrid
vigour, well known in the art.
[1180] Where relevant, the transgenic plants may also comprise
additional transgenes encoding enzymes involved in the production
of non-polar lipid such as, but not limited to LPAAT, LPCAT, PAP,
or a phospholipid:diacylglycerol acyltransferase (PDAT1, PDAT2 or
PDAT3; see for example, Ghosal et al., 2007), or a combination of
two or more thereof. The transgenic plants of the invention may
also express oleosin from an exogenous polynucleotide.
Transformation of Plants
[1181] Transgenic plants can be produced using techniques known in
the art, such as those generally described in Slater et al., Plant
Biotechnology--The Genetic Manipulation of Plants, Oxford
University Press (2003), and Christou and Klee, Handbook of Plant
Biotechnology, John Wiley and Sons (2004).
[1182] As used herein, the terms "stably transforming", "stably
transformed" and variations thereof refer to the integration of the
polynucleotide into the genome of the cell such that they are
transferred to progeny cells during cell division without the need
for positively selecting for their presence. Stable transformants,
or progeny thereof, can be selected by any means known in the art
such as Southern blots on chromosomal DNA, or in situ hybridization
of genomic DNA.
[1183] Agrobacterium-mediated transfer is a widely applicable
system for introducing genes into plant cells because DNA can be
introduced into cells in whole plant tissues, plant organs, or
explants in tissue culture, for either transient expression, or for
stable integration of the DNA in the plant cell genome. The use of
Agrobacterium-mediated plant integrating vectors to introduce DNA
into plant cells is well known in the art (see for example, U.S.
Pat. Nos. 5,177,010, 5,104,310, 5,004,863, or U.S. Pat. No.
5,159,135). The region of DNA to be transferred is defined by the
border sequences, and the intervening DNA (T-DNA) is usually
inserted into the plant genome. Further, the integration of the
T-DNA is a relatively precise process resulting in few
rearrangements. In those plant varieties where
Agrobacterium-mediated transformation is efficient, it is the
method of choice because of the facile and defined nature of the
gene transfer. Preferred Agrobacterium transformation vectors are
capable of replication in E. coli as well as Agrobacterium,
allowing for convenient manipulations as described (Klee et al.,
In: Plant DNA Infectious Agents, Hohn and Schell, eds.,
Springer-Verlag, New York, pp. 179-203 (1985)).
[1184] Acceleration methods that may be used include for example,
microprojectile bombardment and the like. One example of a method
for delivering transforming nucleic acid molecules to plant cells
is microprojectile bombardment. This method has been reviewed by
Yang et al., Particle Bombardment Technology for Gene Transfer,
Oxford Press, Oxford, England (1994). Non-biological particles
(microprojectiles) that may be coated with nucleic acids and
delivered into cells by a propelling force. Exemplary particles
include those comprised of tungsten, gold, platinum, and the like.
A particular advantage of microprojectile bombardment, in addition
to it being an effective means of reproducibly transforming
monocots, is that neither the isolation of protoplasts, nor the
susceptibility of Agrobacterium infection are required. An
illustrative embodiment of a method for delivering DNA into Zea
mays cells by acceleration is a biolistics .alpha.-particle
delivery system, that can be used to propel particles coated with
DNA through a screen such as a stainless steel or Nytex screen,
onto a filter surface covered with corn cells cultured in
suspension. A particle delivery system suitable for use with the
present invention is the helium acceleration PDS-1000/He gun
available from Bio-Rad Laboratories.
[1185] For the bombardment, cells in suspension may be concentrated
on filters. Filters containing the cells to be bombarded are
positioned at an appropriate distance below the microprojectile
stopping plate. If desired, one or more screens are also positioned
between the gun and the cells to be bombarded.
[1186] Alternatively, immature embryos or other target cells may be
arranged on solid culture medium. The cells to be bombarded are
positioned at an appropriate distance below the microprojectile
stopping plate. If desired, one or more screens are also positioned
between the acceleration device and the cells to be bombarded.
Through the use of techniques set forth herein, one may obtain up
to 1000 or more foci of cells transiently expressing a marker gene.
The number of cells in a focus that express the gene product 48
hours post-bombardment often range from one to ten and average one
to three.
[1187] In bombardment transformation, one may optimize the
pre-bombardment culturing conditions and the bombardment parameters
to yield the maximum numbers of stable transformants. Both the
physical and biological parameters for bombardment are important in
this technology. Physical factors are those that involve
manipulating the DNA/microprojectile precipitate or those that
affect the flight and velocity of either the macro- or
microprojectiles. Biological factors include all steps involved in
manipulation of cells before and immediately after bombardment, the
osmotic adjustment of target cells to help alleviate the trauma
associated with bombardment, and also the nature of the
transforming DNA such as linearized DNA or intact supercoiled
plasmids. It is believed that pre-bombardment manipulations are
especially important for successful transformation of immature
embryos.
[1188] In another alternative embodiment, plastids can be stably
transformed. Methods disclosed for plastid transformation in higher
plants include particle gun delivery of DNA containing a selectable
marker and targeting of the DNA to the plastid genome through
homologous recombination (U.S. Pat. Nos. 5,451,513, 5,545,818,
5,877,402, 5,932,479, and WO 99/05265).
[1189] Accordingly, it is contemplated that one may wish to adjust
various aspects of the bombardment parameters in small scale
studies to fully optimize the conditions. One may particularly wish
to adjust physical parameters such as gap distance, flight
distance, tissue distance, and helium pressure. One may also
minimize the trauma reduction factors by modifying conditions that
influence the physiological state of the recipient cells and that
may therefore influence transformation and integration
efficiencies. For example, the osmotic state, tissue hydration and
the subculture stage, or cell cycle of the recipient cells, may be
adjusted for optimum transformation. The execution of other routine
adjustments will be known to those of skill in the art in light of
the present disclosure.
[1190] Transformation of plant protoplasts can be achieved using
methods based on calcium phosphate precipitation, polyethylene
glycol treatment, electroporation, and combinations of these
treatments. Application of these systems to different plant
varieties depends upon the ability to regenerate that particular
plant strain from protoplasts. Illustrative methods for the
regeneration of cereals from protoplasts are described (Fujimura et
al., 1985; Toriyama et al., 1986; Abdullah et al., 1986).
[1191] Other methods of cell transformation can also be used and
include but are not limited to the introduction of DNA into plants
by direct DNA transfer into pollen, by direct injection of DNA into
reproductive organs of a plant, or by direct injection of DNA into
the cells of immature embryos followed by the rehydration of
desiccated embryos.
[1192] The regeneration, development, and cultivation of plants
from single plant protoplast transformants or from various
transformed explants is well known in the art (Weissbach et al.,
In: Methods for Plant Molecular Biology, Academic Press, San Diego,
Calif., (1988)). This regeneration and growth process typically
includes the steps of selection of transformed cells, culturing
those individualized cells through the usual stages of embryonic
development through the rooted plantlet stage. Transgenic embryos
and seeds are similarly regenerated. The resulting transgenic
rooted shoots are thereafter planted in an appropriate plant growth
medium such as soil.
[1193] The development or regeneration of plants containing the
foreign, exogenous gene is well known in the art. Preferably, the
regenerated plants are self-pollinated to provide homozygous
transgenic plants. Otherwise, pollen obtained from the regenerated
plants is crossed to seed-grown plants of agronomically important
lines. Conversely, pollen from plants of these important lines is
used to pollinate regenerated plants. A transgenic plant of the
present invention containing a desired polynucleotide is cultivated
using methods well known to one skilled in the art.
[1194] Methods for transforming dicots, primarily by use of
Agrobacterium tumefaciens, and obtaining transgenic plants have
been published for cotton (U.S. Pat. Nos. 5,004,863, 5,159,135,
5,518,908), soybean (U.S. Pat. Nos. 5,569,834, 5,416,011), Brassica
(U.S. Pat. No. 5,463,174), peanut (Cheng et al., 1996), and pea
(Grant et al., 1995).
[1195] Methods for transformation of cereal plants such as wheat
and barley for introducing genetic variation into the plant by
introduction of an exogenous nucleic acid and for regeneration of
plants from protoplasts or immature plant embryos are well known in
the art, see for example, CA 2,092,588, AU 61781/94, AU 667939,
U.S. Pat. No. 6,100,447, WO 97/048814, U.S. Pat. Nos. 5,589,617,
6,541,257, and other methods are set out in WO 99/14314.
Preferably, transgenic wheat or barley plants are produced by
Agrobacterium tumefaciens mediated transformation procedures.
Vectors carrying the desired polynucleotide may be introduced into
regenerable wheat cells of tissue cultured plants or explants, or
suitable plant systems such as protoplasts.
[1196] The regenerable wheat cells are preferably from the
scutellum of immature embryos, mature embryos, callus derived from
these, or the meristematic tissue.
[1197] To confirm the presence of the transgenes in transgenic
cells and plants, a polymerase chain reaction (PCR) amplification
or Southern blot analysis can be performed using methods known to
those skilled in the art. Expression products of the transgenes can
be detected in any of a variety of ways, depending upon the nature
of the product, and include Western blot and enzyme assay. One
particularly useful way to quantitate protein expression and to
detect replication in different plant tissues is to use a reporter
gene such as GUS. Once transgenic plants have been obtained, they
may be grown to produce plant tissues or parts having the desired
phenotype. The plant tissue or plant parts, may be harvested,
and/or the seed collected. The seed may serve as a source for
growing additional plants with tissues or parts having the desired
characteristics. Preferably, the vegetative plant parts are
harvested at a time when the yield of non-polar lipids are at their
highest. In one embodiment, the vegetative plant parts are
harvested about at the time of flowering.
[1198] A transgenic plant formed using Agrobacterium or other
transformation methods typically contains a single genetic locus on
one chromosome. Such transgenic plants can be referred to as being
hemizygous for the added gene(s). More preferred is a transgenic
plant that is homozygous for the added gene(s), that is, a
transgenic plant that contains two added genes, one gene at the
same locus on each chromosome of a chromosome pair. A homozygous
transgenic plant can be obtained by self-fertilising a hemizygous
transgenic plant, germinating some of the seed produced and
analyzing the resulting plants for the gene of interest.
[1199] It is also to be understood that two different transgenic
plants that contain two independently segregating exogenous genes
or loci can also be crossed (mated) to produce offspring that
contain both sets of genes or loci. Selfing of appropriate FI
progeny can produce plants that are homozygous for both exogenous
genes or loci. Back-crossing to a parental plant and out-crossing
with a non-transgenic plant are also contemplated, as is vegetative
propagation. Descriptions of other breeding methods that are
commonly used for different traits and crops can be found in Fehr,
In: Breeding Methods for Cultivar Development, Wilcox J. ed.,
American Society of Agronomy, Madison Wis. (1987).
Tilling
[1200] In one embodiment, TILLING (Targeting Induced Local Lesions
IN Genomes) can be used to produce plants in which endogenous genes
are knocked out, for example genes encoding a DGAT, sn-1
glycerol-3-phosphate acyltransferase (GPAT),
1-acyl-glycerol-3-phosphate acyltransferase (LPAAT),
acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT),
phosphatidic acid phosphatase (PAP), or a combination of two or
more thereof.
[1201] In a first step, introduced mutations such as novel single
base pair changes are induced in a population of plants by treating
seeds (or pollen) with a chemical mutagen, and then advancing
plants to a generation where mutations will be stably inherited.
DNA is extracted, and seeds are stored from all members of the
population to create a resource that can be accessed repeatedly
over time.
[1202] For a TILLING assay, PCR primers are designed to
specifically amplify a single gene target of interest. Specificity
is especially important if a target is a member of a gene family or
part of a polyploid genome. Next, dye-labeled primers can be used
to amplify PCR products from pooled DNA of multiple individuals.
These PCR products are denatured and reannealed to allow the
formation of mismatched base pairs. Mismatches, or heteroduplexes,
represent both naturally occurring single nucleotide polymorphisms
(SNPs) (i.e., several plants from the population are likely to
carry the same polymorphism) and induced SNPs (i.e., only rare
individual plants are likely to display the mutation). After
heteroduplex formation, the use of an endonuclease, such as Cell,
that recognizes and cleaves mismatched DNA is the key to
discovering novel SNPs within a TILLING population.
[1203] Using this approach, many thousands of plants can be
screened to identify any individual with a single base change as
well as small insertions or deletions (1-30 bp) in any gene or
specific region of the genome. Genomic fragments being assayed can
range in size anywhere from 0.3 to 1.6 kb. At 8-fold pooling, 1.4
kb fragments (discounting the ends of fragments where SNP detection
is problematic due to noise) and 96 lanes per assay, this
combination allows up to a million base pairs of genomic DNA to be
screened per single assay, making TILLING a high-throughput
technique. TILLING is further described in Slade and Knauf (2005),
and Henikoff et al. (2004).
[1204] In addition to allowing efficient detection of mutations,
high-throughput TILLING technology is ideal for the detection of
natural polymorphisms. Therefore, interrogating an unknown
homologous DNA by heteroduplexing to a known sequence reveals the
number and position of polymorphic sites. Both nucleotide changes
and small insertions and deletions are identified, including at
least some repeat number polymorphisms. This has been called
Ecotilling (Comai et al., 2004).
[1205] Each SNP is recorded by its approximate position within a
few nucleotides. Thus, each haplotype can be archived based on its
mobility. Sequence data can be obtained with a relatively small
incremental effort using aliquots of the same amplified DNA that is
used for the mismatch-cleavage assay. The left or right sequencing
primer for a single reaction is chosen by its proximity to the
polymorphism. Sequencher software performs a multiple alignment and
discovers the base change, which in each case confirmed the gel
band.
[1206] Ecotilling can be performed more cheaply than full
sequencing, the method currently used for most SNP discovery.
Plates containing arrayed ecotypic DNA can be screened rather than
pools of DNA from mutagenized plants. Because detection is on gels
with nearly base pair resolution and background patterns are
uniform across lanes, bands that are of identical size can be
matched, thus discovering and genotyping SNPs in a single step. In
this way, ultimate sequencing of the SNP is simple and efficient,
made more so by the fact that the aliquots of the same PCR products
used for screening can be subjected to DNA sequencing.
Enhancing Exogenous RNA Levels and Stabilized Expression
[1207] Post-transcriptional gene silencing (PTGS) is a nucleotide
sequence-specific defense mechanism that can target both cellular
and viral mRNAs for degradation. PTGS occurs in plants or fungi
stably or transiently transformed with a recombinant
polynucleotide(s) and results in the reduced accumulation of RNA
molecules with sequence similarity to the introduced
polynucleotide. "Post-transcriptional" refers to a mechanism
operating at least partly, but not necessarily exclusively, after
production of an initial RNA transcript, for example during
processing of the initial RNA transcript, or concomitant with
splicing or export of the RNA to the cytoplasm, or within the
cytoplasm by complexes associated with Argonaute proteins.
[1208] RNA molecule levels can be increased, and/or RNA molecule
levels stabilized over numerous generations or under different
environmental conditions, by limiting the expression of a silencing
suppressor in a storage organ of a plant or part thereof. As used
herein, a "silencing suppressor" is any polynucleotide or
polypeptide that can be expressed in a plant cell that enhances the
level of expression product from a different transgene in the plant
cell, particularly, over repeated generations from the initially
transformed plant. In an embodiment, the silencing suppressor is a
viral silencing suppressor or mutant thereof. A large number of
viral silencing suppressors are known in the art and include, but
are not limited to P19, V2, P38, Pe-Po and RPV-P0. Examples of
suitable viral silencing suppressors include those described in WO
2010/057246. A silencing suppressor may be stably expressed in a
plant or part thereof of the present invention.
[1209] As used herein, the term "stably expressed" or variations
thereof refers to the level of the RNA molecule being essentially
the same or higher in progeny plants over repeated generations, for
example, at least three, at least five, or at least ten
generations, when compared to corresponding plants lacking the
exogenous polynucleotide encoding the silencing suppressor.
However, this term(s) does not exclude the possibility that over
repeated generations there is some loss of levels of the RNA
molecule when compared to a previous generation, for example, not
less than a 10% loss per generation.
[1210] The suppressor can be selected from any source e.g. plant,
viral, mammal, etc. The suppressor may be, for example, flock house
virus B2, pothos latent virus P14, pothos latent virus AC2, African
cassava mosaic virus AC4, bhendi yellow vein mosaic disease C2,
bhendi yellow vein mosaic disease C4, bhendi yellow vein mosaic
disease .beta.C1, tomato chlorosis virus p22, tomato chlorosis
virus CP, tomato chlorosis virus CPm, tomato golden mosaic virus
AL2, tomato leaf curl Java virus .beta.C1, tomato yellow leaf curl
virus V2, tomato yellow leaf curl virus-China C2, tomato yellow
leaf curl China virus Y10 isolate .beta.C1, tomato yellow leaf curl
Israeli isolate V2, mungbean yellow mosaic virus-Vigna AC2,
hibiscus chlorotic ringspot virus CP, turnip crinkle virus P38,
turnip crinkle virus CP, cauliflower mosaic virus P6, beet yellows
virus p21, citrus tristeza virus p20, citrus tristeza virus p23,
citrus tristeza virus CP, cowpea mosaic virus SCP, sweet potato
chlorotic stunt virus p22, cucumber mosaic virus 2b, tomato aspermy
virus HC-Pro, beet curly top virus L2, soil borne wheat mosaic
virus 19K, barley stripe mosaic virus Gammab, poa semilatent virus
Gammab, peanut clump pecluvirus P15, rice dwarf virus Pns10,
curubit aphid borne yellows virus P0, beet western yellows virus
P0, potato virus X P25, cucumber vein yellowing virus P1b, plum pox
virus HC-Pro, sugarcane mosaic virus HC-Pro, potato virus Y strain
HC-Pro, tobacco etch virus P1/HC-Pro, turnip mosaic virus
P1/HC-Pro, cocksfoot mottle virus P1, cocksfoot mottle
virus-Norwegian isolate P1, rice yellow mottle virus P1, rice
yellow mottle virus-Nigerian isolate P1, rice hoja blanca virus
NS3, rice stripe virus NS3, crucifer infecting tobacco mosaic virus
126K, crucifer infecting tobacco mosaic virus p122, tobacco mosaic
virus p122, tobacco mosaic virus 126, tobacco mosaic virus 130K,
tobacco rattle virus 16K, tomato bushy stunt virus P19, tomato
spotted wilt virus NSs, apple chlorotic leaf spot virus P50,
grapevine virus A p10, grapevine leafroll associated virus-2
homolog of BYV p21, as well as variants/mutants thereof. The list
above provides the virus from which the suppressor can be obtained
and the protein (e.g., B2, P14, etc.), or coding region designation
for the suppressor from each particular virus. Other candidate
silencing suppressors may be obtained by examining viral genome
sequences for polypeptides encoded at the same position within the
viral genome, relative to the structure of a related viral genome
comprising a known silencing suppressor, as is appreciated by a
person of skill in the art.
[1211] Silencing suppressors can be categorized based on their mode
of action. Suppressors such as V2 which preferentially bind to a
double-stranded RNA molecule which has overhanging 5' ends relative
to a corresponding double-stranded RNA molecule having blunt ends
are particularly useful for enhancing transgene expression when
used in combination with gene silencing (exogenous polynucleotide
encoding a dsRNA). Other suppressors such as p19 which
preferentially bind a dsRNA molecule which is 21 base pairs in
length relative to a dsRNA molecule of a different length can also
allow transgene expression in the presence of an exogenous
polynucleotide encoding a dsRNA, but generally to a lesser degree
than, for example, V2. This allows the selection of an optimal
combination of dsRNA, silencing suppressor and over-expressed
transgene for a particular purpose. Such optimal combinations can
be identified using a method of the invention.
[1212] In an embodiment, the silencing suppressor preferentially
binds to a double-stranded RNA molecule which has overhanging 5'
ends relative to a corresponding double-stranded RNA molecule
having blunt ends. In this context, the corresponding
double-stranded RNA molecule preferably has the same nucleotide
sequence as the molecule with the 5' overhanging ends, but without
the overhanging 5' ends. Binding assays are routinely performed,
for example in in vitro assays, by any method as known to a person
of skill in the art.
[1213] Multiple copies of a suppressor may be used. Different
suppressors may be used together (e. g., in tandem).
[1214] Essentially any RNA molecule which is desirable to be
expressed in a plant storage organ can be co-expressed with the
silencing suppressor. The RNA molecule may influence an agronomic
trait, insect resistance, disease resistance, herbicide resistance,
sterility, grain characteristics, and the like. The encoded
polypeptides may be involved in metabolism of lipid, starch,
carbohydrates, nutrients, etc., or may be responsible for the
synthesis of proteins, peptides, lipids, waxes, starches, sugars,
carbohydrates, flavors, odors, toxins, carotenoids. hormones,
polymers, flavonoids, storage proteins, phenolic acids, alkaloids,
lignins, tannins, celluloses, glycoproteins, glycolipids, etc.
[1215] In a particular example, the plants produced increased
levels of enzymes for lipid production in plants such as Brassicas,
for example oilseed rape or sunflower, safflower, flax, cotton,
soya bean or maize.
Plant Biomass
[1216] An increase in the total lipid content of plant biomass
equates to greater energy content, making its use in the production
of biofuel more economical.
[1217] Plant biomass is the organic materials produced by plants,
such as leaves, roots, seeds, and stalks. Plant biomass is a
complex mixture of organic materials, such as carbohydrates, fats,
and proteins, along with small amounts of minerals, such as sodium,
phosphorus, calcium, and iron. The main components of plant biomass
are carbohydrates (approximately 75%, dry weight) and lignin
(approximately 25%), which can vary with plant type. The
carbohydrates are mainly cellulose or hemicellulose fibers, which
impart strength to the plant structure, and lignin, which holds the
fibers together. Some plants also store starch (another
carbohydrate polymer) and fats as sources of energy, mainly in
seeds and roots (such as corn, soybeans, and potatoes).
[1218] Plant biomass typically has a low energy density as a result
of both its physical form and moisture content. This makes it
inconvenient and inefficient for storage and transport, and also
usually unsuitable for use without some kind of pre-processing.
[1219] There are a range of processes available to convert it into
a more convenient form including: 1) physical pre-processing (for
example, grinding) or 2) conversion by thermal (for example,
combustion, gasification, pyrolysis) or chemical (for example,
anaerobic digestion, fermentation, composting, transesterification)
processes. In this way, the biomass is converted into what can be
described as a biomass fuel.
Combustion
[1220] Combustion is the process by which flammable materials are
allowed to burn in the presence of air or oxygen with the release
of heat. The basic process is oxidation. Combustion is the simplest
method by which biomass can be used for energy, and has been used
to provide heat. This heat can itself be used in a number of ways:
1) space heating, 2) water (or other fluid) heating for central or
district heating or process heat, 3) steam raising for electricity
generation or motive force. When the flammable fuel material is a
form of biomass the oxidation is of predominantly the carbon (C)
and hydrogen (H) in the cellulose, hemicellulose, lignin, and other
molecules present to form carbon dioxide (CO.sub.2) and water
(H.sub.2O).
Gasification
[1221] Gasification is a partial oxidation process whereby a carbon
source such as plant biomass, is broken down into carbon monoxide
(CO) and hydrogen (H.sub.2), plus carbon dioxide (CO.sub.2) and
possibly hydrocarbon molecules such as methane (CH.sub.4). If the
gasification takes place at a relatively low temperature, such as
700.degree. C. to 1000.degree. C., the product gas will have a
relatively high level of hydrocarbons compared to high temperature
gasification. As a result it may be used directly, to be burned for
heat or electricity generation via a steam turbine or, with
suitable gas clean up, to run an internal combustion engine for
electricity generation. The combustion chamber for a simple boiler
may be close coupled with the gasifier, or the producer gas may be
cleaned of longer chain hydrocarbons (tars), transported, stored
and burned remotely. A gasification system may be closely
integrated with a combined cycle gas turbine for electricity
generation (IGCC--integrated gasification combined cycle). Higher
temperature gasification (1200.degree. C. to 1600.degree. C.) leads
to few hydrocarbons in the product gas, and a higher proportion of
CO and H.sub.2. This is known as synthesis gas (syngas or
biosyngas) as it can be used to synthesize longer chain
hydrocarbons using techniques such as Fischer-Tropsch (FT)
synthesis. If the ratio of H.sub.2 to CO is correct (2:1) FT
synthesis can be used to convert syngas into high quality synthetic
diesel biofuel which is compatible with conventional fossil diesel
and diesel engines.
Pyrolysis
[1222] As used herein, the term "pyrolysis" means a process that
uses slow heating in the absence of oxygen to produce gaseous, oil
and char products from biomass. Pyrolysis is a thermal or
thermo-chemical conversion of lipid-based, particularly
triglyceride-based, materials. The products of pyrolysis include
gas, liquid and a sold char, with the proportions of each depending
upon the parameters of the process. Lower temperatures (around
400.degree. C.) tend to produce more solid char (slow pyrolysis),
whereas somewhat higher temperatures (around 500.degree. C.)
produce a much higher proportion of liquid (bio-oil), provided the
vapour residence time is kept down to around Is or less. After
this, secondary reactions take place and increase the gas yield.
The bio-oil produced by fast (higher temperature) pyrolysis is a
dark brown, mobile liquid with a heating value about half that of
conventional fuel oil. It can be burned directly, co-fired,
upgraded to other fuels or gasified.
[1223] Pyrolysis involves direct thermal cracking of the lipids or
a combination of thermal and catalytic cracking. At temperatures of
about 400-500.degree. C., cracking occurs, producing short chain
hydrocarbons such as alkanes, alkenes, alkadienes, aromatics,
olefins and carboxylic acid, as well as carbon monoxide and carbon
dioxide.
[1224] Four main catalyst types can be used including transition
metal catalysts, molecular sieve type catalysts, activated alumina
and sodium carbonate (Maher et al., 2007). Examples are given in
U.S. Pat. No. 4,102,938. Alumina (Al.sub.2O.sub.3) activated by
acid is an effective catalyst (U.S. Pat. No. 5,233,109). Molecular
sieve catalysts are porous, highly crystalline structures that
exhibit size selectivity, so that molecules of only certain sizes
can pass through. These include zeolite catalysts such as ZSM-5 or
HZSM-5 which are crystalline materials comprising AlO.sub.4 and
SiO.sub.4 and other silica-alumina catalysts. The activity and
selectivity of these catalysts depends on the acidity, pore size
and pore shape, and typically operate at 300-500.degree. C.
Transition metal catalysts are described for example in U.S. Pat.
No. 4,992,605. Sodium carbonate catalyst has been used in the
pyrolysis of oils (Dandik and Aksoy, 1998).
Transesterification
[1225] "Transesterification" as used herein is the conversion of
lipids, principally triacylglycerols, into fatty acid methyl esters
or ethyl esters using short chain alcohols such as methanol or
ethanol, in the presence of a catalyst such as alkali or acid.
[1226] Methanol is used more commonly due to low cost and
availability. The catalysts may be homogeneous catalysts,
heterogeneous catalysts or enzymatic catalysts. Homogeneous
catalysts include ferric sulphate followed by KOH. Heterogeneous
catalysts include CaO, K.sub.3PO.sub.4, and WO.sub.3/ZrO.sub.2.
Enzymatic catalysts include Novozyme 435 produced from Candida
antarctica.
Anaerobic Digestion
[1227] Anaerobic digestion is the process whereby bacteria break
down organic material in the absence of air, yielding a biogas
containing methane. The products of this process are biogas
(principally methane (CH.sub.4) and carbon dioxide (CO.sub.2)), a
solid residue (fibre or digestate) that is similar, but not
identical, to compost and a liquid liquor that can be used as a
fertilizer. The methane can be burned for heat or electricity
generation. The solid residue of the anaerobic digestion process
can be used as a soil conditioner or alternatively can be burned as
a fuel, or gasified.
[1228] Anaerobic digestion is typically performed on biological
material in an aqueous slurry. However there are an increasing
number of dry digesters. Mesophilic digestion takes place between
20.degree. C. and 40.degree. C. and can take a month or two to
complete. Thermophilic digestion takes place from 50-65.degree. C.
and is faster, but the bacteria are more sensitive.
Fermentation
[1229] Conventional fermentation processes for the production of
bioalcohol make use of the starch and sugar components of plant
crops. Second generation bioalcohol precedes this with acid and/or
enzymatic hydrolysis of hemicellulose and cellulose into
fermentable saccharides to make use of a much larger proportion of
available biomass. More detail is provided below under the heading
"Fermentation processes for lipid production".
Composting
[1230] Composting is the aerobic decomposition of organic matter by
microorganisms. It is typically performed on relatively dry
material rather than a slurry. Instead of, or in addition to,
collecting the flammable biogas emitted, the exothermic nature of
the composting process can be exploited and the heat produced used,
usually using a heat pump.
Production of Non-Polar Lipids
[1231] Techniques that are routinely practiced in the art can be
used to extract, process, purify and analyze the non-polar lipids
produced by cells, organisms or parts thereof of the instant
invention. Such techniques are described and explained throughout
the literature in sources such as, Fereidoon Shahidi, Current
Protocols in Food Analytical Chemistry, John Wiley & Sons, Inc.
(2001) D1.1.1-D1.1.11, and Perez-Vich et al. (1998).
Production of Seedoil
[1232] Typically, plant seeds are cooked, pressed, and/or extracted
to produce crude seedoil, which is then degummed, refined,
bleached, and deodorized. Generally, techniques for crushing seed
are known in the art. For example, oilseeds can be tempered by
spraying them with water to raise the moisture content to, for
example, 8.5%, and flaked using a smooth roller with a gap setting
of 0.23 to 0.27 mm. Depending on the type of seed, water may not be
added prior to crushing. Application of heat deactivates enzymes,
facilitates further cell rupturing, coalesces the lipid droplets,
and agglomerates protein particles, all of which facilitate the
extraction process.
[1233] In an embodiment, the majority of the seedoil is released by
passage through a screw press. Cakes expelled from the screw press
are then solvent extracted for example, with hexane, using a heat
traced column. Alternatively, crude seedoil produced by the
pressing operation can be passed through a settling tank with a
slotted wire drainage top to remove the solids that are expressed
with the seedoil during the pressing operation. The clarified
seedoil can be passed through a plate and frame filter to remove
any remaining fine solid particles. If desired, the seedoil
recovered from the extraction process can be combined with the
clarified seedoil to produce a blended crude seedoil.
[1234] Once the solvent is stripped from the crude seedoil, the
pressed and extracted portions are combined and subjected to normal
lipid processing procedures (i.e., degumming, caustic refining,
bleaching, and deodorization).
[1235] In an embodiment, the oil and/or protein content of the seed
is analysed by near-infrared reflectance spectroscopy as described
in Hom et al. (2007).
[1236] Degumming
[1237] Degumming is an early step in the refining of oils and its
primary purpose is the removal of most of the phospholipids from
the oil, which may be present as approximately 1-2% of the total
extracted lipid. Addition of .about.2% of water, typically
containing phosphoric acid, at 70-80.degree. C. to the crude oil
results in the separation of most of the phospholipids accompanied
by trace metals and pigments. The insoluble material that is
removed is mainly a mixture of phospholipids and triacylglycerols
and is also known as lecithin. Degumming can be performed by
addition of concentrated phosphoric acid to the crude seedoil to
convert non-hydratable phosphatides to a hydratable form, and to
chelate minor metals that are present. Gum is separated from the
seedoil by centrifugation. The seedoil can be refined by addition
of a sufficient amount of a sodium hydroxide solution to titrate
all of the fatty acids and removing the soaps thus formed.
[1238] Alkali Refining
[1239] Alkali refining is one of the refining processes for
treating crude oil, sometimes also referred to as neutralization.
It usually follows degumming and precedes bleaching. Following
degumming, the seedoil can treated by the addition of a sufficient
amount of an alkali solution to titrate all of the fatty acids and
phosphoric acids, and removing the soaps thus formed. Suitable
alkaline materials include sodium hydroxide, potassium hydroxide,
sodium carbonate, lithium hydroxide, calcium hydroxide, calcium
carbonate and ammonium hydroxide. This process is typically carried
out at room temperature and removes the free fatty acid fraction.
Soap is removed by centrifugation or by extraction into a solvent
for the soap, and the neutralised oil is washed with water. If
required, any excess alkali in the oil may be neutralized with a
suitable acid such as hydrochloric acid or sulphuric acid.
[1240] Bleaching
[1241] Bleaching is a refining process in which oils are heated at
90-120.degree. C. for 10-30 minutes in the presence of a bleaching
earth (0.2-2.0%) and in the absence of oxygen by operating with
nitrogen or steam or in a vacuum. This step in oil processing is
designed to remove unwanted pigments (carotenoids, chlorophyll,
gossypol etc), and the process also removes oxidation products,
trace metals, sulphur compounds and traces of soap.
[1242] Deodorization
[1243] Deodorization is a treatment of oils and fats at a high
temperature (200-260.degree. C.) and low pressure (0.1-1 mm Hg).
This is typically achieved by introducing steam into the seedoil at
a rate of about 0.1 ml/minute/100 ml of seedoil. Deodorization can
be performed by heating the seedoil to 260.degree. C. under vacuum,
and slowly introducing steam into the seedoil at a rate of about
0.1 ml/minute/100 ml of seedoil. After about 30 minutes of
sparging, the seedoil is allowed to cool under vacuum. The seedoil
is typically transferred to a glass container and flushed with
argon before being stored under refrigeration. If the amount of
seedoil is limited, the seedoil can be placed under vacuum for
example, in a Parr reactor and heated to 260.degree. C. for the
same length of time that it would have been deodorized. This
treatment improves the colour of the seedoil and removes a majority
of the volatile substances or odorous compounds including any
remaining free fatty acids, monoacylglycerols and oxidation
products.
[1244] Winterisation
[1245] Winterization is a process sometimes used in commercial
production of oils for the separation of oils and fats into solid
(stearin) and liquid (olein) fractions by crystallization at
sub-ambient temperatures. It was applied originally to cottonseed
oil to produce a solid-free product. It is typically used to
decrease the saturated fatty acid content of oils.
Plant Biomass for the Production of Lipids
[1246] Parts of plants involved in photosynthesis (e.g., and stems
and leaves of higher plants and aquatic plants such as algae) can
also be used to produce lipid. Independent of the type of plant,
there are several methods for extracting lipids from green biomass.
One way is physical extraction, which often does not use solvent
extraction. It is a "traditional" way using several different types
of mechanical extraction. Expeller pressed extraction is a common
type, as are the screw press and ram press extraction methods. The
amount of lipid extracted using these methods varies widely,
depending upon the plant material and the mechanical process
employed. Mechanical extraction is typically less efficient than
solvent extraction described below.
[1247] In solvent extraction, an organic solvent (e.g., hexane) is
mixed with at least the genetically modified plant green biomass,
preferably after the green biomass is dried and ground. Of course,
other parts of the plant besides the green biomass (e.g.,
lipid-containing seeds) can be ground and mixed in as well. The
solvent dissolves the lipid in the biomass and the like, which
solution is then separated from the biomass by mechanical action
(e.g., with the pressing processes above). This separation step can
also be performed by filtration (e.g., with a filter press or
similar device) or centrifugation etc. The organic solvent can then
be separated from the non-polar lipid (e.g., by distillation). This
second separation step yields non-polar lipid from the plant and
can yield a re-usable solvent if one employs conventional vapor
recovery.
[1248] If, for instance, vegetative tissue as described herein, is
not to be used immediately to extract, and/or process, the lipid it
is preferably handled post-harvest to ensure the lipid content does
not decrease, or such that any decrease in lipid content is
minimized as much as possible (see, for example, Christie, 1993).
In one embodiment, the vegetative tissue is frozen as soon as
possible after harvesting using, for example, dry ice or liquid
nitrogen. In another embodiment, the vegetative tissue is stored at
a cold temperature, for example -20.degree. C. or -60.degree. C. in
an atmosphere of nitrogen.
Algae for the Production of Lipids
[1249] Algae can produce 10 to 100 times as much mass as
terrestrial plants in a year. In addition to being a prolific
organism, algae are also capable of producing oils and starches
that can be converted into biofuels.
[1250] The specific algae most useful for biofuel production are
known as microalgae, consisting of small, often unicellular, types.
These algae can grow almost anywhere. With more than 100,000 known
species of diatoms (a type of alga), 40,000 known species of green
plant-like algae, and smaller numbers of other algae species, algae
will grow rapidly in nearly any environment, with almost any kind
of water. Specifically, useful algae can be grown in marginal areas
with limited or poor quality water, such as in the arid and mostly
empty regions of the American Southwest. These areas also have
abundant sunshine for photosynthesis. In short, algae can be an
ideal organism for production of biofuels--efficient growth,
needing no premium land or water, not competing with food crops,
needing much smaller amounts of land than food crops, and storing
energy in a desirable form.
[1251] Algae can store energy in its cell structure in the form of
either oil or starch. Stored oil can be as much as 60% of the
weight of the algae. Certain species which are highly prolific in
oil or starch production have been identified, and growing
conditions have been tested. Processes for extracting and
converting these materials to fuels have also been developed.
[1252] The most common oil-producing algae can generally include,
or consist essentially of, the diatoms (bacillariophytes), green
algae (chlorophytes), blue-green algae (cyanophytes), and
golden-brown algae (chrysophytes). In addition a fifth group known
as haptophytes may be used. Groups include brown algae and
heterokonts. Specific non-limiting examples algae include the
Classes: Chlorophyceae, Eustigmatophyceae, Prymnesiophyceae,
Bacillariophyceae. Bacillariophytes capable of oil production
include the genera Amphipleura, Amphora, Chaetoceros, Cyclotella,
Cymbella, Fragilaria, Hantzschia, Navicula, Nitzschia,
Phaeodactylum, and Thalassiosira. Specific non-limiting examples of
chlorophytes capable of oil production include Ankistrodesmus,
Botryococcus, Chlorella, Chlorococcum, Dunaliella, Monoraphidium,
Oocystis, Scenedesmus, and Tetrasehnis. In one aspect, the
chlorophytes can be Chlorella or Dunaliella. Specific non-limiting
examples of cyanophytes capable of oil production include
Oscillatoria and Synechococcus. A specific example of chrysophytes
capable of oil production includes Boekelovia. Specific
non-limiting examples of haptophytes include Isochysis and
Pleurochysis.
[1253] Specific algae useful in the present invention include, for
example, Chlamydomonas sp. such as Chlamydomonas reinhardii,
Dunaliella sp. such as Dunaliella salina, Dunaliella tertiolecta,
D. acidophila, D. bardawil, D. bioculata, D. lateralis, D.
maritima, D. minuta, D. parva, D. peircei, D. polymorpha, D.
primolecta, D. pseudosalina, D. quartolecta. D. viridis,
Haematococcus sp., Chlorella sp. such as Chlorella vulgaris,
Chlorella sorokiniana or Chlorella protothecoides, Thraustochytrium
sp., Schizochytrium sp., Volvox sp, Nannochloropsis sp.,
Botryococcus braunii which can contain over 60 wt % lipid,
Phaeodactylum ricornutum, Thalassiosira pseudonana, Isochrysis sp.,
Pavlova sp., Chlorococcum sp, Ellipsoidion sp., Neochloris sp.,
Scenedesmus sp.
[1254] Further, the oil-producing algae of the present invention
can include a combination of an effective amount of two or more
strains in order to maximize benefits from each strain. As a
practical matter, it can be difficult to achieve 100% purity of a
single strain of algae or a combination of desired algae strains.
However, when discussed herein, the oil-producing algae is intended
to cover intentionally introduced strains of algae, while foreign
strains are preferably minimized and kept below an amount which
would detrimentally affect yields of desired oil-producing algae
and algal oil. Undesirable algae strains can be controlled and/or
eliminated using any number of techniques. For example, careful
control of the growth environment can reduce introduction of
foreign strains. Alternatively, or in addition to other techniques,
a virus selectively chosen to specifically target only the foreign
strains can be introduced into the growth reservoirs in an amount
which is effective to reduce and/or eliminate the foreign strain.
An appropriate virus can be readily identified using conventional
techniques. For example, a sample of the foreign algae will most
often include small amounts of a virus which targets the foreign
algae. This virus can be isolated and grown in order to produce
amounts which would effectively control or eliminate the foreign
algae population among the more desirable oil-producing algae.
[1255] Algaculture is a form of aquaculture involving the farming
of species of algae (including microalgae, also referred to as
phytoplankton, microphytes, or planktonic algae, and macroalgae,
commonly known as seaweed).
[1256] Commercial and industrial algae cultivation has numerous
uses, including production of food ingredients, food, and algal
fuel.
[1257] Mono or mixed algal cultures can be cultured in open-ponds
(such as raceway-type ponds and lakes) or photobioreactors.
[1258] Algae can be harvested using microscreens, by
centrifugation, by flocculation (using for example, chitosan, alum
and ferric chloride) and by froth flotation. Interrupting the
carbon dioxide supply can cause algae to flocculate on its own,
which is called "autoflocculation". In froth flotation, the
cultivator aerates the water into a froth, and then skims the algae
from the top. Ultrasound and other harvesting methods are currently
under development.
[1259] Lipid may be separated from the algae by mechanical
crushing. When algae is dried it retains its lipid content, which
can then be "pressed" out with an oil press. Since different
strains of algae vary widely in their physical attributes, various
press configurations (screw, expeller, piston, etc.) work better
for specific algae types.
[1260] Osmotic shock is sometimes used to release cellular
components such as lipid from algae. Osmotic shock is a sudden
reduction in osmotic pressure and can cause cells in a solution to
rupture.
[1261] Ultrasonic extraction can accelerate extraction processes,
in particular enzymatic extraction processes employed to extract
lipid from algae. Ultrasonic waves are used to create cavitation
bubbles in a solvent material. When these bubbles collapse near the
cell walls, the resulting shock waves and liquid jets cause those
cells walls to break and release their contents into a solvent.
[1262] Chemical solvents (for example, hexane, benzene, petroleum
ether) are often used in the extraction of lipids from algae.
Soxhlet extraction can be use to extract lipids from algae through
repeated washing, or percolation, with an organic solvent under
reflux in a special glassware.
[1263] Enzymatic extraction may be used to extract lipids from
algae. Ezymatic extraction uses enzymes to degrade the cell walls
with water acting as the solvent. The enzymatic extraction can be
supported by ultrasonication.
[1264] Supercritical CO.sub.2 can also be used as a solvent. In
this method, CO.sub.2 is liquefied under pressure and heated to the
point that it becomes supercritical (having properties of both a
liquid and a gas), allowing it to act as a solvent.
Fermentation Processes for Lipid Production
[1265] As used herein, the term the "fermentation process" refers
to any fermentation process or any process comprising a
fermentation step. A fermentation process includes, without
limitation, fermentation processes used to produce alcohols (e.g.,
ethanol, methanol, butanol), organic acids (e.g., citric acid,
acetic acid, itaconic acid, lactic acid, gluconic acid), ketones
(e.g., acetone), amino acids (e.g., glutamic acid), gases (e.g.,
H.sub.2 and CO.sub.2), antibiotics (e.g., penicillin and
tetracycline), enzymes, vitamins (e.g., riboflavin, beta-carotene),
and hormones. Fermentation processes also include fermentation
processes used in the consumable alcohol industry (e.g., beer and
wine), dairy industry (e.g., fermented dairy products), leather
industry and tobacco industry. Preferred fermentation processes
include alcohol fermentation processes, as are well known in the
art. Preferred fermentation processes are anaerobic fermentation
processes, as are well known in the art. Suitable fermenting cells,
typically microorganisms that are able to ferment, that is,
convert, sugars such as glucose or maltose, directly or indirectly
into the desired fermentation product.
[1266] Examples of fermenting microorganisms include fungal
organisms such as yeast, preferably an oleaginous organism. As used
herein, an "oleaginous organism" is one which accumulates at least
25% of its dry weight as triglycerides. As used herein, "yeast"
includes Saccharomyces spp., Saccharomyces cerevisiae,
Saccharomyces carlbergensis, Candida spp., Kiuveromyces spp.,
Pichia spp., Hansenula spp., Trichoderma spp., Lipomyces starkey,
and Yarrowia lipolytica. Preferred yeast include Yarrowia
lipolytica or other oleaginous yeasts and strains of the
Saccharomyces spp., and in particular, Saccharomyces
cerevisiae.
[1267] In one embodiment, the fermenting microorganism is a
transgenic organism that comprises one or more exogenous
polynucleotides, wherein the transgenic organism has an increased
level of one or more non-polar lipids when compared to a
corresponding organism lacking the one or more exogenous
polynucleotides. The transgenic microorganism is preferably grown
under conditions that optimize activity of fatty acid biosynthetic
genes and fatty acid acyltransferase genes. This leads to
production of the greatest and the most economical yield of lipid.
In general, media conditions that may be optimized include the type
and amount of carbon source, the type and amount of nitrogen
source, the carbon-to-nitrogen ratio, the oxygen level, growth
temperature, pH, length of the biomass production phase, length of
the lipid accumulation phase and the time of cell harvest.
[1268] Fermentation media must contain a suitable carbon source.
Suitable carbon sources may include, but are not limited to:
monosaccharides (e.g., glucose, fructose), disaccharides (e.g.,
lactose, sucrose), oligosaccharides, polysaccharides (e.g., starch,
cellulose or mixtures thereof), sugar alcohols (e.g., glycerol) or
mixtures from renewable feedstocks (e.g., cheese whey permeate,
cornsteep liquor, sugar beet molasses, barley malt). Additionally,
carbon sources may include alkanes, fatty acids, esters of fatty
acids, monoglycerides, diglycerides, triglycerides, phospholipids
and various commercial sources of fatty acids including vegetable
oils (e.g., soybean oil) and animal fats. Additionally, the carbon
substrate may include one-carbon substrates (e.g., carbon dioxide,
methanol, formaldehyde, formate, carbon-containing amines) for
which metabolic conversion into key biochemical intermediates has
been demonstrated. Hence it is contemplated that the source of
carbon utilized in the present invention may encompass a wide
variety of carbon-containing substrates and will only be limited by
the choice of the host microorganism. Although all of the above
mentioned carbon substrates and mixtures thereof are expected to be
suitable in the present invention, preferred carbon substrates are
sugars and/or fatty acids. Most preferred is glucose and/or fatty
acids containing between 10-22 carbons. Nitrogen may be supplied
from an inorganic (e.g., (NH.sub.4).sub.2SO.sub.4) or organic
source (e.g., urea, glutamate). In addition to appropriate carbon
and nitrogen sources, the fermentation media may also contain
suitable minerals, salts, cofactors, buffers, vitamins and other
components known to those skilled in the art suitable for the
growth of the microorganism and promotion of the enzymatic pathways
necessary for lipid production.
[1269] A suitable pH range for the fermentation is typically
between about pH 4.0 to pH 8.0, wherein pH 5.5 to pH 7.0 is
preferred as the range for the initial growth conditions. The
fermentation may be conducted under aerobic or anaerobic
conditions, wherein microaerobic conditions are preferred.
[1270] Typically, accumulation of high levels of lipid in the cells
of oleaginous microorganisms requires a two-stage process, since
the metabolic state must be "balanced" between growth and
synthesis/storage of fats. Thus, most preferably, a two-stage
fermentation process is necessary for the production of lipids in
microorganisms. In this approach, the first stage of the
fermentation is dedicated to the generation and accumulation of
cell mass and is characterized by rapid cell growth and cell
division. In the second stage of the fermentation, it is preferable
to establish conditions of nitrogen deprivation in the culture to
promote high levels of lipid accumulation. The effect of this
nitrogen deprivation is to reduce the effective concentration of
AMP in the cells, thereby reducing the activity of the
NAD-dependent isocitrate dehydrogenase of mitochondria. When this
occurs, citric acid will accumulate, thus forming abundant pools of
acetyl-CoA in the cytoplasm and priming fatty acid synthesis. Thus,
this phase is characterized by the cessation of cell division
followed by the synthesis of fatty acids and accumulation of
TAGs.
[1271] Although cells are typically grown at about 30.degree. C.,
some studies have shown increased synthesis of unsaturated fatty
acids at lower temperatures. Based on process economics, this
temperature shift should likely occur after the first phase of the
two-stage fermentation, when the bulk of the microorganism's growth
has occurred.
[1272] It is contemplated that a variety of fermentation process
designs may be applied, where commercial production of lipids using
the instant nucleic acids is desired. For example, commercial
production of lipid from a recombinant microbial host may be
produced by a batch, fed-batch or continuous fermentation
process.
[1273] A batch fermentation process is a closed system wherein the
media composition is set at the beginning of the process and not
subject to further additions beyond those required for maintenance
of pH and oxygen level during the process. Thus, at the beginning
of the culturing process the media is inoculated with the desired
organism and growth or metabolic activity is permitted to occur
without adding additional substrates (i.e., carbon and nitrogen
sources) to the medium. In batch processes the metabolite and
biomass compositions of the system change constantly up to the time
the culture is terminated. In a typical batch process, cells
moderate through a static lag phase to a high-growth log phase and
finally to a stationary phase, wherein the growth rate is
diminished or halted. Left untreated, cells in the stationary phase
will eventually die. A variation of the standard batch process is
the fed-batch process, wherein the substrate is continually added
to the fermentor over the course of the fermentation process. A
fed-batch process is also suitable in the present invention.
Fed-batch processes are useful when catabolite repression is apt to
inhibit the metabolism of the cells or where it is desirable to
have limited amounts of substrate in the media at any one time.
Measurement of the substrate concentration in fed-batch systems is
difficult and therefore may be estimated on the basis of the
changes of measurable factors such as pH, dissolved oxygen and the
partial pressure of waste gases (e.g., CO.sub.2). Batch and
fed-batch culturing methods are common and well known in the art
and examples may be found in Brock, In Biotechnology: A Textbook of
Industrial Microbiology, 2.sup.nd ed., Sinauer Associates,
Sunderland, Mass., (1989); or Deshpande (1992).
[1274] Commercial production of lipid using the instant cells may
also be accomplished by a continuous fermentation process, wherein
a defined media is continuously added to a bioreactor while an
equal amount of culture volume is removed simultaneously for
product recovery. Continuous cultures generally maintain the cells
in the log phase of growth at a constant cell density. Continuous
or semi-continuous culture methods permit the modulation of one
factor or any number of factors that affect cell growth or end
product concentration. For example, one approach may limit the
carbon source and allow all other parameters to moderate
metabolism. In other systems, a number of factors affecting growth
may be altered continuously while the cell concentration, measured
by media turbidity, is kept constant. Continuous systems strive to
maintain steady state growth and thus the cell growth rate must be
balanced against cell loss due to media being drawn off the
culture. Methods of modulating nutrients and growth factors for
continuous culture processes, as well as techniques for maximizing
the rate of product formation, are well known in the art of
industrial microbiology and a variety of methods are detailed by
Brock, supra.
[1275] Fatty acids, including PUFAs, may be found in the host
microorganism as free fatty acids or in esterified forms such as
acylglycerols, phospholipids, sulfolipids or glycolipids, and may
be extracted from the host cell through a variety of means
well-known in the art.
[1276] In general, means for the purification of fatty acids,
including PUFAs, may include extraction with organic solvents,
sonication, supercritical fluid extraction (e.g., using carbon
dioxide), saponification and physical means such as presses, or
combinations thereof. Of particular interest is extraction with
methanol and chloroform in the presence of water (Bligh and Dyer,
1959). Where desirable, the aqueous layer can be acidified to
protonate negatively-charged moieties and thereby increase
partitioning of desired products into the organic layer. After
extraction, the organic solvents can be removed by evaporation
under a stream of nitrogen. When isolated in conjugated forms, the
products may be enzymatically or chemically cleaved to release the
free fatty acid or a less complex conjugate of interest, and can
then be subject to further manipulations to produce a desired end
product. Desirably, conjugated forms of fatty acids are cleaved
with potassium hydroxide.
[1277] If further purification is necessary, standard methods can
be employed. Such methods may include extraction, treatment with
urea, fractional crystallization, HPLC, fractional distillation,
silica gel chromatography, high-speed centrifugation or
distillation, or combinations of these techniques. Protection of
reactive groups such as the acid or alkenyl groups, may be done at
any step through known techniques (e.g., alkylation, iodination).
Methods used include methylation of the fatty acids to produce
methyl esters. Similarly, protecting groups may be removed at any
step. Desirably, purification of fractions containing GLA, STA,
ARA, DHA and EPA may be accomplished by treatment with urea and/or
fractional distillation.
[1278] An example of the use of plant biomass for the production of
a biomass slurry using yeast is described in WO 2011/100272.
Uses of Lipids
[1279] The lipids produced by the methods described have a variety
of uses. In some embodiments, the lipids are used as food oils. In
other embodiments, the lipids are refined and used as lubricants or
for other industrial uses such as the synthesis of plastics. In
some preferred embodiments, the lipids are refined to produce
biodiesel.
Biofuel
[1280] As used herein the term "biofuel" includes biodiesel and
bioalcohol. Biodiesel can be made from oils derived from plants,
algae and fungi. Bioalcohol is produced from the fermentation of
sugar. This sugar can be extracted directly from plants (e.g.,
sugarcane), derived from plant starch (e.g., maize or wheat) or
made from cellulose (e.g., wood, leaves or stems).
[1281] Biofuels currently cost more to produce than petroleum
fuels. In addition to processing costs, biofuel crops require
planting, fertilising, pesticide and herbicide applications,
harvesting and transportation. Plants, algae and fungi of the
present invention may reduce production costs of biofuel.
[1282] General methods for the production of biofuel can be found
in, for example, Maher and Bressler, 2007; Greenwell et al., 2010;
Karmakar et al., 2010; Alonso et al., 2010; Lee and Mohamed, 2010;
Liu et al., 2010a; Gong and Jiang, 2011; Endalew et al., 2011;
Semwal et al., 2011.
[1283] Bioalcohol
[1284] The production of biologically produced alcohols, for
example, ethanol, propanol and butanol is well known. Ethanol is
the most common bioalcohol.
[1285] The basic steps for large scale production of ethanol are:
1) microbial (for example, yeast) fermentation of sugars, 2)
distillation, 3) dehydration, and optionally 4) denaturing. Prior
to fermentation, some crops require saccharification or hydrolysis
of carbohydrates such as cellulose and starch into sugars.
Saccharification of cellulose is called cellulolysis. Enzymes can
be used to convert starch into sugar.
[1286] Fermentation
[1287] Bioalcohol is produced by microbial fermentation of the
sugar. Microbial fermentation will currently only work directly
with sugars. Two major components of plants, starch and cellulose,
are both made up of sugars, and can in principle be converted to
sugars for fermentation.
[1288] Distillation
[1289] For the ethanol to be usable as a fuel, the majority of the
water must be removed. Most of the water is removed by
distillation, but the purity is limited to 95-96% due to the
formation of a low-boiling water-ethanol azeotrope with maximum
(95.6% m/m (96.5% v/v) ethanol and 4.4% m/m (3.5% v/v) water). This
mixture is called hydrous ethanol and can be used as a fuel alone,
but unlike anhydrous ethanol, hydrous ethanol is not miscible in
all ratios with gasoline, so the water fraction is typically
removed in further treatment in order to burn in combination with
gasoline in gasoline engines.
[1290] Dehydration
[1291] Water can be removed from from an azeotropic ethanol/water
mixture by dehydration. Azeotropic distillation, used in many early
fuel ethanol plants, consists of adding benzene or cyclohexane to
the mixture. When these components are added to the mixture, it
forms a heterogeneous azeotropic mixture in vapor-liquid-liquid
equilibrium, which when distilled produces anhydrous ethanol in the
column bottom, and a vapor mixture of water and
cyclohexane/benzene. When condensed, this becomes a two-phase
liquid mixture. Another early method, called extractive
distillation, consists of adding a ternary component which will
increase ethanol's relative volatility. When the ternary mixture is
distilled, it will produce anhydrous ethanol on the top stream of
the column.
[1292] A third method has emerged and has been adopted by the
majority of modern ethanol plants. This new process uses molecular
sieves to remove water from fuel ethanol. In this process, ethanol
vapor under pressure passes through a bed of molecular sieve beads.
The bead's pores are sized to allow absorption of water while
excluding ethanol. After a period of time, the bed is regenerated
under vacuum or in the flow of inert atmosphere (e.g. N.sub.2) to
remove the absorbed water. Two beds are often used so that one is
available to absorb water while the other is being regenerated.
[1293] Biodiesel
[1294] The production of biodiesel, or alkyl esters, is well known.
There are three basic routes to ester production from lipids: 1)
Base catalysed transesterification of the lipid with alcohol; 2)
Direct acid catalysed esterification of the lipid with methanol;
and 3) Conversion of the lipid to fatty acids, and then to alkyl
esters with acid catalysis.
[1295] Any method for preparing fatty acid alkyl esters and
glyceryl ethers (in which one, two or three of the hydroxy groups
on glycerol are etherified) can be used. For example, fatty acids
can be prepared, for example, by hydrolyzing or saponifying
triglycerides with acid or base catalysts, respectively, or using
an enzyme such as a lipase or an esterase. Fatty acid alkyl esters
can be prepared by reacting a fatty acid with an alcohol in the
presence of an acid catalyst. Fatty acid alkyl esters can also be
prepared by reacting a triglyceride with an alcohol in the presence
of an acid or base catalyst. Glycerol ethers can be prepared, for
example, by reacting glycerol with an alkyl halide in the presence
of base, or with an olefin or alcohol in the presence of an acid
catalyst.
[1296] In some preferred embodiments, the lipids are
transesterified to produce methyl esters and glycerol. In some
preferred embodiments, the lipids are reacted with an alcohol (such
as methanol or ethanol) in the presence of a catalyst (for example,
potassium or sodium hydroxide) to produce alkyl esters. The alkyl
esters can be used for biodiesel or blended with petroleum based
fuels.
[1297] The alkyl esters can be directly blended with diesel fuel,
or washed with water or other aqueous solutions to remove various
impurities, including the catalysts, before blending. It is
possible to neutralize acid catalysts with base. However, this
process produces salt. To avoid engine corrosion, it is preferable
to minimize the salt concentration in the fuel additive
composition. Salts can be substantially removed from the
composition, for example, by washing the composition with
water.
[1298] In another embodiment, the composition is dried after it is
washed, for example, by passing the composition through a drying
agent such as calcium sulfate.
[1299] In yet another embodiment, a neutral fuel additive is
obtained without producing salts or using a washing step, by using
a polymeric acid, such as Dowex 50.TM., which is a resin that
contains sulfonic acid groups. The catalyst is easily removed by
filtration after the esterification and etherification reactions
are complete.
[1300] Plant Triacylglycerols as a Biofuel Source
[1301] Use of plant triacylglycerols for the production of biofuel
is reviewed in Durrett et al. (2008). Briefly, plant oils are
primarily composed of various triacylglycerols (TAGs), molecules
that consist of three fatty acid chains (usually 18 or 16 carbons
long) esterified to glycerol. The fatty acyl chains are chemically
similar to the aliphatic hydrocarbons that make up the bulk of the
molecules found in petrol and diesel. The hydrocarbons in petrol
contain between 5 and 12 carbon atoms per molecule, and this
volatile fuel is mixed with air and ignited with a spark in a
conventional engine. In contrast, diesel fuel components typically
have 10-15 carbon atoms per molecule and are ignited by the very
high compression obtained in a diesel engine. However, most plant
TAGs have a viscosity range that is much higher than that of
conventional diesel: 17.3-32.9 mm.sup.2s.sup.-1 compared to 1.9-4.1
mm.sup.2s-1, respectively (ASTM D975; Knothe and Steidley, 2005).
This higher viscosity results in poor fuel atomization in modem
diesel engines, leading to problems derived from incomplete
combustion such as carbon deposition and coking (Ryan et al.,
1984). To overcome this problem, TAGs are converted to less viscous
fatty acid esters by esterification with a primary alcohol, most
commonly methanol. The resulting fuel is commonly referred to as
biodiesel and has a dynamic viscosity range from 1.9 to 6.0
mm.sup.2s.sup.-1(ASTM D6751). The fatty acid methyl esters (FAMEs)
found in biodiesel have a high energy density as reflected by their
high heat of combustion, which is similar, if not greater, than
that of conventional diesel (Knothe, 2005). Similarly, the cetane
number (a measure of diesel ignition quality) of the FAMEs found in
biodiesel exceeds that of conventional diesel (Knothe, 2005).
[1302] Plant oils are mostly composed of five common fatty acids,
namely palmitate (16:0), stearate (18:0), oleate (18:1), linoleate
(18:2) and linolenate (18:3), although, depending on the particular
species, longer or shorter fatty acids may also be major
constituents. These fatty acids differ from each other in terms of
acyl chain length and number of double bonds, leading to different
physical properties. Consequently, the fuel properties of biodiesel
derived from a mixture of fatty acids are dependent on that
composition. Altering the fatty acid profile can therefore improve
fuel properties of biodiesel such as cold-temperature flow
characteristics, oxidative stability and NOx emissions. Altering
the fatty acid composition of TAGs may reduce the viscosity of the
plant oils, eliminating the need for chemical modification, thus
improving the cost-effectiveness of biofuels.
[1303] Most plant oils are derived from triacylglycerols stored in
seeds. However, the present invention provides methods for also
increasing oil content in vegetative tissues. The plant tissues of
the present invention have an increased total lipid yield.
Furthermore, the level of oleic acid is increased significantly
while the polyunsaturated fatty acid alpha linolenic acid was
reduced.
[1304] Once a leaf is developed, it undergoes a developmental
change from sink (absorbing nutrients) to source (providing
sugars). In food crops, most sugars are translocated out of source
leaves to support growth of new leaves, roots and fruits. Because
translocation of carbohydrate is an active process, there is a loss
of carbon and energy during translocation. Furthermore, after the
developing seed takes up carbon from the plant, there are
additional carbon and energy losses associated with the conversion
of carbohydrate into the oil, protein or other major components of
the seed (Goffman et al., 2005). Plants of the present invention
increase the energy content of leaves and/or stems such that the
whole above-ground plant may be harvested and used to produce
biofuel.
[1305] Algae as a Biofuel Source
[1306] Algae store oil inside the cell body, sometimes but not
always in vesicles. This oil can be recovered in several relatively
simple ways, including solvents, heat, and/or pressure. However,
these methods typically recover only about 80% to 90% of the stored
oil. Processes which offer more effective oil extraction methods
which can recover close to 100% of the stored oil at low cost as
known in the art. These processes include or consist of
depolymerizing, such as biologically breaking the walls of the
algal cell and/or oil vesicles, if present, to release the oil from
the oil-producing algae.
[1307] In addition, a large number of viruses exist which invade
and rupture algae cells, and can thereby release the contents of
the cell in particular stored oil or starch. Such viruses are an
integral part of the algal ecosystem, and many of the viruses are
specific to a single type of algae. Specific examples of such
viruses include the chlorella virus PBCV-1 (Paramecium Bursaria
Chlorella Virus) which is specific to certain Chlorella algae, and
cyanophages such as SM-1, P-60, and AS-1 specific to the blue-green
algae Synechococcus. The particular virus selected will depend on
the particular species of algae to be used in the growth process.
One aspect of the present invention is the use of such a virus to
rupture the algae so that oil contained inside the algae cell wall
can be recovered. In another detailed aspect of the present
invention, a mixture of biological agents can be used to rupture
the algal cell wall and/or oil vesicles.
[1308] Mechanical crushing, for example, an expeller or press, a
hexane or butane solvent recovery step, supercritical fluid
extraction, or the like can also be useful in extracting the oil
from oil vesicles of the oil-producing algae. Alternatively,
mechanical approaches can be used in combination with biological
agents in order to improve reaction rates and/or separation of
materials. Regardless of the particular biological agent or agents
chosen such can be introduced in amounts which are sufficient to
serve as the primary mechanism by which algal oil is released from
oil vesicles in the oil-producing algae, i.e. not a merely
incidental presence of any of these.
[1309] Once the oil has been released from the algae it can be
recovered or separated 16 from a slurry of algae debris material,
for example, cellular residue, oil, enzyme, by-products, etc. This
can be done by sedimentation or centrifugation, with centrifugation
generally being faster. Starch production can follow similar
separation processes.
[1310] An algal feed can be formed from a biomass feed source as
well as an algal feed source. Biomass from either algal or
terrestrial sources can be depolymerized in a variety of ways such
as, but not limited to saccharification, hydrolysis or the like.
The source material can be almost any sufficiently voluminous
cellulose, lignocellulose, polysaccharide or carbohydrate,
glycoprotein, or other material making up the cell wall of the
source material.
[1311] The fermentation stage can be conventional in its use of
yeast to ferment sugar to alcohol. The fermentation process
produces carbon dioxide, alcohol, and algal husks. All of these
products can be used elsewhere in the process and systems of the
present invention, with substantially no unused material or wasted
heat. Alternatively, if ethanol is so produced, it can be sold as a
product or used to produce ethyl acetate for the
transesterification process. Similar considerations would apply to
alcohols other than ethanol.
[1312] Algal oil can be converted to biodiesel through a process of
direct hydrogenation or transesterification of the algal oil. Algal
oil is in a similar form as most vegetable oils, which are in the
form of triglycerides. A triglyceride consists of three fatty acid
chains, one attached to each of the three carbon atoms in a
glycerol backbone. This form of oil can be burned directly.
However, the properties of the oil in this form are not ideal for
use in a diesel engine, and without modification, the engine will
soon run poorly or fail. In accordance with the present invention,
the triglyceride is converted into biodiesel, which is similar to
but superior to petroleum diesel fuel in many respects.
[1313] One process for converting the triglyceride to biodiesel is
transesterification, and includes reacting the triglyceride with
alcohol or other acyl acceptor to produce free fatty acid esters
and glycerol. The free fatty acids are in the form of fatty acid
alkyl esters (FAAE).
[1314] With the chemical process, additional steps are needed to
separate the catalyst and clean the fatty acids. In addition, if
ethanol is used as the acyl acceptor, it must be essentially dry to
prevent production of soap via saponification in the process, and
the glycerol must be purified. The biological process, by
comparison, can accept ethanol in a less dry state and the cleaning
and purification of the biodiesel and glycerol are much easier.
[1315] Transesterification often uses a simple alcohol, typically
methanol derived from petroleum. When methanol is used the
resultant biodiesel is called fatty acid methyl ester (FAME) and
most biodiesel sold today, especially in Europe, is FAME. However,
ethanol can also be used as the alcohol in transesterification, in
which case the biodiesel is fatty acid ethyl ester (FAEE). In the
US, the two types are usually not distinguished, and are
collectively known as fatty acid alkyl esters (FAAE), which as a
generic term can apply regardless of the acyl acceptor used. Direct
hydrogenation can also be utilized to convert at least a portion of
the algal oil to a biodiesel. As such, in one aspect, the biodiesel
product can include an alkane.
[1316] The algal triglyceride can also be converted to biodiesel by
direct hydrogenation. In this process, the products are alkane
chains, propane, and water. The glycerol backbone is hydrogenated
to propane, so there is substantially no glycerol produced as a
byproduct. Furthermore, no alcohol or transesterification catalysts
are needed. All of the biomass can be used as feed for the
oil-producing algae with none needed for fermentation to produce
alcohol for transesterification. The resulting alkanes are pure
hydrocarbons, with no oxygen, so the biodiesel produced in this way
has a slightly higher energy content than the alkyl esters,
degrades more slowly, does not attract water, and has other
desirable chemical properties.
Feedstuffs
[1317] The present invention includes compositions which can be
used as feedstuffs.
[1318] For purposes of the present invention, "feedstuffs" include
any food or preparation for human or animal consumption (including
for enteral and/or parenteral consumption) which when taken into
the body: (1) serve to nourish or build up tissues or supply
energy, and/or (2) maintain, restore or support adequate
nutritional status or metabolic function. Feedstuffs of the
invention include nutritional compositions for babies and/or young
children.
[1319] Feedstuffs of the invention comprise for example, a cell of
the invention, a plant of the invention, the plant part of the
invention, the seed of the invention, an extract of the invention,
the product of a method of the invention, the product of a
fermentation process of the invention, or a composition along with
a suitable carrier(s). The term "carrier" is used in its broadest
sense to encompass any component which may or may not have
nutritional value. As the person skilled in the art will
appreciate, the carrier must be suitable for use (or used in a
sufficiently low concentration) in a feedstuff, such that it does
not have deleterious effect on an organism which consumes the
feedstuff.
[1320] The feedstuff of the present invention comprises a lipid
produced directly or indirectly by use of the methods, cells or
organisms disclosed herein. The composition may either be in a
solid or liquid form. Additionally, the composition may include
edible macronutrients, vitamins, and/or minerals in amounts desired
for a particular use. The amounts of these ingredients will vary
depending on whether the composition is intended for use with
normal individuals or for use with individuals having specialized
needs such as individuals suffering from metabolic disorders and
the like.
[1321] Examples of suitable carriers with nutritional value
include, but are not limited to, macronutrients such as edible
fats, carbohydrates and proteins. Examples of such edible fats
include, but are not limited to, coconut oil, borage oil, fungal
oil, black current oil, soy oil, and mono- and di-glycerides.
Examples of such carbohydrates include, but are not limited to,
glucose, edible lactose, and hydrolyzed starch. Additionally,
examples of proteins which may be utilized in the nutritional
composition of the invention include, but are not limited to, soy
proteins, electrodialysed whey, electrodialysed skim milk, milk
whey, or the hydrolysates of these proteins.
[1322] With respect to vitamins and minerals, the following may be
added to the feedstuff compositions of the present invention,
calcium, phosphorus, potassium, sodium, chloride, magnesium,
manganese, iron, copper, zinc, selenium, iodine, and vitamins A, E,
D, C, and the B complex. Other such vitamins and minerals may also
be added.
[1323] The components utilized in the feedstuff compositions of the
present invention can be of semi-purified or purified origin. By
semi-purified or purified is meant a material which has been
prepared by purification of a natural material or by de novo
synthesis.
[1324] A feedstuff composition of the present invention may also be
added to food even when supplementation of the diet is not
required. For example, the composition may be added to food of any
type, including, but not limited to, margarine, modified butter,
cheeses, milk, yogurt, chocolate, candy, snacks, salad oils,
cooking oils, cooking fats, meats, fish and beverages.
[1325] The genus Saccharomyces spp is used in both brewing of beer
and wine making and also as an agent in baking, particularly bread.
Yeast is a major constituent of vegetable extracts. Yeast is also
used as an additive in animal feed. It will be apparent that
genetically modified yeast strains can be provided which are
adapted to synthesize lipid as described herein. These yeast
strains can then be used in food stuffs and in wine and beer making
to provide products which have enhanced lipid content.
[1326] Additionally, lipid produced in accordance with the present
invention or host cells transformed to contain and express the
subject genes may also be used as animal food supplements to alter
an animal's tissue or milk fatty acid composition to one more
desirable for human or animal consumption. Examples of such animals
include sheep, cattle, horses and the like.
[1327] Furthermore, feedstuffs of the invention can be used in
aquaculture to increase the levels of fatty acids in fish for human
or animal consumption.
[1328] Preferred feedstuffs of the invention are the plants, seed
and other plant parts such as leaves, fruits and stems which may be
used directly as food or feed for humans or other animals. For
example, animals may graze directly on such plants grown in the
field, or be fed more measured amounts in controlled feeding. The
invention includes the use of such plants and plant parts as feed
for increasing the polyunsaturated fatty acid levels in humans and
other animals.
Compositions
[1329] The present invention also encompasses compositions,
particularly pharmaceutical compositions, comprising one or more
lipids produced using the methods of the invention.
[1330] A pharmaceutical composition may comprise one or more of the
lipids, in combination with a standard, well-known, non-toxic
pharmaceutically-acceptable carrier, adjuvant or vehicle such as
phosphate-buffered saline, water, ethanol, polyols, vegetable oils,
a wetting agent, or an emulsion such as a water/oil emulsion. The
composition may be in either a liquid or solid form. For example,
the composition may be in the form of a tablet, capsule, ingestible
liquid, powder, topical ointment or cream. Proper fluidity can be
maintained for example, by the maintenance of the required particle
size in the case of dispersions and by the use of surfactants. It
may also be desirable to include isotonic agents for example,
sugars, sodium chloride, and the like. Besides such inert diluents,
the composition can also include adjuvants such as wetting agents,
emulsifying and suspending agents, sweetening agents, flavoring
agents and perfuming agents.
[1331] Suspensions, in addition to the active compounds, may
comprise suspending agents such as ethoxylated isostearyl alcohols,
polyoxyethylene sorbitol and sorbitan esters, microcrystalline
cellulose, aluminum metahydroxide, bentonite, agar-agar, and
tragacanth, or mixtures of these substances.
[1332] Solid dosage forms such as tablets and capsules can be
prepared using techniques well known in the art. For example, lipid
produced in accordance with the present invention can be tableted
with conventional tablet bases such as lactose, sucrose, and
cornstarch in combination with binders such as acacia, cornstarch
or gelatin, disintegrating agents such as potato starch or alginic
acid, and a lubricant such as stearic acid or magnesium stearate.
Capsules can be prepared by incorporating these excipients into a
gelatin capsule along with antioxidants and the relevant
lipid(s).
[1333] For intravenous administration, the lipids produced in
accordance with the present invention or derivatives thereof may be
incorporated into commercial formulations.
[1334] A typical dosage of a particular fatty acid is from 0.1 mg
to 20 g, taken from one to five times per day (up to 100 g daily)
and is preferably in the range of from about 10 mg to about 1, 2,
5, or 10 g daily (taken in one or multiple doses). As known in the
art, a minimum of about 300 mg/day of fatty acid, especially
polyunsaturated fatty acid, is desirable. However, it will be
appreciated that any amount of fatty acid will be beneficial to the
subject.
[1335] Possible routes of administration of the pharmaceutical
compositions of the present invention include for example, enteral
and parenteral. For example, a liquid preparation may be
administered orally. Additionally, a homogenous mixture can be
completely dispersed in water, admixed under sterile conditions
with physiologically acceptable diluents, preservatives, buffers or
propellants to form a spray or inhalant.
[1336] The dosage of the composition to be administered to the
subject may be determined by one of ordinary skill in the art and
depends upon various factors such as weight, age, overall health,
past history, immune status, etc., of the subject.
[1337] Additionally, the compositions of the present invention may
be utilized for cosmetic purposes. The compositions may be added to
pre-existing cosmetic compositions, such that a mixture is formed,
or a fatty acid produced according to the invention may be used as
the sole "active" ingredient in a cosmetic composition.
Polypeptides
[1338] The terms "polypeptide" and "protein" are generally used
interchangeably.
[1339] A polypeptide or class of polypeptides may be defined by the
extent of identity (% identity) of its amino acid sequence to a
reference amino acid sequence, or by having a greater % identity to
one reference amino acid sequence than to another. The % identity
of a polypeptide to a reference amino acid sequence is typically
determined by GAP analysis (Needleman and Wunsch, 1970; GCG
program) with parameters of a gap creation penalty=5, and a gap
extension penalty=0.3. The query sequence is at least 100 amino
acids in length and the GAP analysis aligns the two sequences over
a region of at least 100 amino acids. Even more preferably, the
query sequence is at least 250 amino acids in length and the GAP
analysis aligns the two sequences over a region of at least 250
amino acids. Even more preferably, the GAP analysis aligns two
sequences over their entire length. The polypeptide or class of
polypeptides may have the same enzymatic activity as, or a
different activity than, or lack the activity of, the reference
polypeptide. Preferably, the polypeptide has an enzymatic activity
of at least 10% of the activity of the reference polypeptide.
[1340] As used herein a "biologically active fragment" is a portion
of a polypeptide of the invention which maintains a defined
activity of a full-length reference polypeptide for example, MGAT
activity. Biologically active fragments as used herein exclude the
full-length polypeptide. Biologically active fragments can be any
size portion as long as they maintain the defined activity.
Preferably, the biologically active fragment maintains at least 10%
of the activity of the full length polypeptide.
[1341] With regard to a defined polypeptide or enzyme, it will be
appreciated that % identity figures higher than those provided
herein will encompass preferred embodiments. Thus, where
applicable, in light of the minimum % identity figures, it is
preferred that the polypeptide/enzyme comprises an amino acid
sequence which is at least 60%, more preferably at least 65%, more
preferably at least 70%, more preferably at least 75%, more
preferably at least 80%, more preferably at least 85%, more
preferably at least 90%, more preferably at least 91%, more
preferably at least 92%, more preferably at least 93%, more
preferably at least 94%, more preferably at least 95%, more
preferably at least 96%, more preferably at least 97%, more
preferably at least 98%, more preferably at least 99%, more
preferably at least 99.1%, more preferably at least 99.2%, more
preferably at least 99.3%, more preferably at least 99.4%, more
preferably at least 99.5%, more preferably at least 99.6%, more
preferably at least 99.7%, more preferably at least 99.8%, and even
more preferably at least 99.9% identical to the relevant nominated
SEQ ID NO.
[1342] Amino acid sequence mutants of the polypeptides defined
herein can be prepared by introducing appropriate nucleotide
changes into a nucleic acid defined herein, or by in vitro
synthesis of the desired polypeptide. Such mutants include for
example, deletions, insertions, or substitutions of residues within
the amino acid sequence. A combination of deletions, insertions and
substitutions can be made to arrive at the final construct,
provided that the final polypeptide product possesses the desired
characteristics.
[1343] Mutant (altered) polypeptides can be prepared using any
technique known in the art, for example, using directed evolution
or rathional design strategies (see below). Products derived from
mutated/altered DNA can readily be screened using techniques
described herein to determine if they possess fatty acid
acyltransferase activity, for example, MGAT, DGAT, or
GPAT/phosphatase activity.
[1344] In designing amino acid sequence mutants, the location of
the mutation site and the nature of the mutation will depend on
characteristic(s) to be modified. The sites for mutation can be
modified individually or in series for example, by (1) substituting
first with conservative amino acid choices and then with more
radical selections depending upon the results achieved, (2)
deleting the target residue, or (3) inserting other residues
adjacent to the located site.
[1345] Amino acid sequence deletions generally range from about 1
to 15 residues, more preferably about 1 to 10 residues and
typically about 1 to 5 contiguous residues.
[1346] Substitution mutants have at least one amino acid residue in
the polypeptide removed and a different residue inserted in its
place. The sites of greatest interest for substitutional
mutagenesis include sites identified as the active site(s). Other
sites of interest are those in which particular residues obtained
from various strains or species are identical. These positions may
be important for biological activity. These sites, especially those
falling within a sequence of at least three other identically
conserved sites, are preferably substituted in a relatively
conservative manner. Such conservative substitutions are shown in
Table 1 under the heading of "exemplary substitutions".
[1347] In a preferred embodiment a mutant/variant polypeptide has
only, or not more than, one or two or three or four conservative
amino acid changes when compared to a naturally occurring
polypeptide. Details of conservative amino acid changes are
provided in Table 1. As the skilled person would be aware, such
minor changes can reasonably be predicted not to alter the activity
of the polypeptide when expressed in a recombinant cell.
TABLE-US-00002 TABLE 1 Exemplary substitutions. Original Exemplary
Residue Substitutions Ala (A) val; leu; ile; gly Arg (R) lys Asn
(N) gln; his Asp (D) glu Cys (C) ser Gln (Q) asn; his Glu (E) asp
Gly (G) pro, ala His (H) asn; gln Ile (I) leu; val; ala Leu (L)
ile; val; met; ala; phe Lys (K) arg Met (M) leu; phe Phe (F) leu;
val; ala Pro (P) gly Ser (S) thr Thr (T) ser Trp (W) tyr Tyr (Y)
trp; phe Val (V) ile; leu; met; phe, ala
Directed Evolution
[1348] In directed evolution, random mutagenesis is applied to a
protein, and a selection regime is used to pick out variants that
have the desired qualities, for example, increased fatty acid
acyltransferase activity. Further rounds of mutation and selection
are then applied. A typical directed evolution strategy involves
three steps:
[1349] 1) Diversification: The gene encoding the protein of
interest is mutated and/or recombined at random to create a large
library of gene variants. Variant gene libraries can be constructed
through error prone PCR (see, for example, Leung, 1989; Cadwell and
Joyce, 1992), from pools of DNasel digested fragments prepared from
parental templates (Stemmer, 1994a; Stemmer, 1994b; Crameri et al.,
1998; Coco et al., 2001) from degenerate oligonucleotides (Ness et
al., 2002, Coco, 2002) or from mixtures of both, or even from
undigested parental templates (Zhao et al., 1998; Eggert et al.,
2005; Jezequek et al., 2008) and are usually assembled through PCR.
Libraries can also be made from parental sequences recombined in
vivo or in vitro by either homologous or non-homologous
recombination (Ostermeier et al., 1999; Volkov et al., 1999; Sieber
et al., 2001). Variant gene libraries can also be constructed by
sub-cloning a gene of interest into a suitable vector, transforming
the vector into a "mutator" strain such as the E. coli XL-1 red
(Stratagene) and propagating the transformed bacteria for a
suitable number of generations. Variant gene libraries can also be
constructed by subjecting the gene of interest to DNA shuffling
(i.e., in vitro homologous recombination of pools of selected
mutant genes by random fragmentation and reassembly) as broadly
described by Harayama (1998).
[1350] 2) Selection: The library is tested for the presence of
mutants (variants) possessing the desired property using a screen
or selection. Screens enable the identification and isolation of
high-performing mutants by hand, while selections automatically
eliminate all nonfunctional mutants. A screen may involve screening
for the presence of known conserved amino acid motifs.
Alternatively, or in addition, a screen may involve expressing the
mutated polynucleotide in a host organsim or part thereof and
assaying the level of fatty acid acyltransferase activity by, for
example, quantifying the level of resultant product in lipid
extracted from the organism or part thereof, and determining the
level of product in the extracted lipid from the organsim or part
thereof relative to a corresponding organism or part thereof
lacking the mutated polynucleotide and optionally, expressing the
parent (unmutated) polynucleotide. Alternatively, the screen may
involve feeding the organism or part thereof labelled substrate and
determining the level of substrate or product in the organsim or
part thereof relative to a corresponding organism or part thereof
lacking the mutated polynucleotide and optionally, expressing the
parent (unmutated) polynucleotide.
[1351] 3) Amplification: The variants identified in the selection
or screen are replicated many fold, enabling researchers to
sequence their DNA in order to understand what mutations have
occurred.
Together, these three steps are termed a "round" of directed
evolution. Most experiments will entail more than one round. In
these experiments, the "winners" of the previous round are
diversified in the next round to create a new library. At the end
of the experiment, all evolved protein or polynucleotide mutants
are characterized using biochemical methods.
Rational Design
[1352] A protein can be designed rationally, on the basis of known
information about protein structure and folding. This can be
accomplished by design from scratch (de novo design) or by redesign
based on native scaffolds (see, for example, Hellinga, 1997; and Lu
and Berry, Protein Structure Design and Engineering, Handbook of
Proteins 2, 1153-1157 (2007)). Protein design typically involves
identifying sequences that fold into a given or target structure
and can be accomplished using computer models. Computational
protein design algorithms search the sequence-conformation space
for sequences that are low in energy when folded to the target
structure. Computational protein design algorithms use models of
protein energetics to evaluate how mutations would affect a
protein's structure and function. These energy functions typically
include a combination of molecular mechanics, statistical (i.e.
knowledge-based), and other empirical terms. Suitable available
software includes IPRO (Interative Protein Redesign and
Optimization), EGAD (A Genetic Algorithm for Protein Design),
Rosetta Design, Sharpen, and Abalone.
[1353] Also included within the scope of the invention are
polypeptides defined herein which are differentially modified
during or after synthesis for example, by biotinylation,
benzylation, glycosylation, acetylation, phosphorylation,
amidation, derivatization by known protecting/blocking groups,
proteolytic cleavage, linkage to an antibody molecule or other
cellular ligand, etc. These modifications may serve to increase the
stability and/or bioactivity of the polypeptide of the
invention.
Identification of Fatty Acid Acyltransferases
[1354] In one aspect, the invention provides a method for
identifying a nucleic acid molecule encoding a fatty acid
acyltransferase having an increased ability to produce MAG, DAG
and/or TAG in a cell.
[1355] The method comprises obtaining a cell comprising a nucleic
acid molecule encoding a fatty acid acyltransferase operably linked
to a promoter which is active in the cell. The nucleic acid
molecule may encode a naturally occurring fatty acid
acyltransferase such as MGAT, GPAT and/or DGAT, or a mutant(s)
thereof. Mutants may be engineered using standard procedures in the
art (see above) such as by performing random mutagenesis, targeted
mutagenesis, or saturation mutagenesis on known genes of interest,
or by subjecting different genes to DNA shuffling. For example, a
polynucleotide comprising a sequence selected from any one of SEQ
ID NOs:1 to 44 which encodes a MGAT may be mutated and/or
recombined at random to create a large library of gene variants
(mutants) using for example, error-prone PCR and/or DNA shuffling.
Mutants may be selected for further investigation on the basis that
they comprise a conserved amino acid motif. For example, in the
case of a candidate nucleic acid encoding a MGAT, a skilled person
may determine whether it comprises a sequence as provided in SEQ ID
NOs:220, 221, 222, 223, and/or 224 before testing whether the
nucleic acid encodes a functional MGAT mutant (by for example,
transfection into a host cell, such as a plant cell and assaying
for fatty acid acyltransferase (i.e., MGAT) activity as described
herein).
[1356] Direct PCR sequencing of the nucleic acid or a fragment
thereof may be used to determine the exact nucleotide sequence and
deduce the corresponding amino acid sequence and thereby identify
conserved amino acid sequences. Degenerate primers based on
conserved amino acid sequences may be used to direct PCR
amplification. Degenerate primers can also be used as probes in DNA
hybridization assays. Alternatively, the conserved amino acid
sequence(s) may be detected in protein hybridization assays that
utilize for example, an antibody that specifically binds to the
conserved amino acid sequences(s), or a substrate that specifically
binds to the conserved amino acid sequences(s) such as, for
example, a lipid that binds FLXLXXXN (a putative neutral lipid
binding domain; SEQ ID NO:224).
[1357] In one embodiment, the nucleic acid molecule comprises a
sequence of nucleotides encoding a MGAT. The sequence of
nucleotides may i) comprise a sequence selected from any one of SEQ
ID NOs:1 to 44, ii) encode a polypeptide comprising amino acids
having a sequence as provided in any one of SEQ ID NOs:45 to 82, or
a biologically active fragment thereof, iii) be at least 50%
identical to i) or ii), or iv) hybridize to any one of i) to iii)
under stringent conditions. In another or additional embodiment,
the nucleic acid molecule comprises a sequence of nucleotides
encoding one or more conserved DGAT2 and/or MGAT1/2 amino acid
sequences as provided in SEQ ID NOs:220, 221, 222, 223, and 224. In
a preferred embodiment, the nucleic acid molecule comprises a
sequence of nucleotides encoding the conserved amino acid sequences
provided in SEQ ID NO:220 and/or SEQ ID NO:224.
[1358] In another embodiment, the nucleic acid molecule comprises a
sequence of nucleotides encoding a GPAT, preferably a GPAT which
has phosphatase activity. The sequence of nucleotides may i)
comprise a sequence selected from any one of SEQ ID NOs:84 to 141,
ii) encode a polypeptide comprising amino acids having a sequence
as provided in any one of SEQ ID NOs:144 to 201, or a biologically
active fragment thereof: iii) be at least 50% identical to i) or
ii), or iv) hybridize to any one of i) to iii) under stringent
conditions. In another or additional embodiment, the nucleic acid
molecule comprises a sequence of nucleotides encoding one or more
conserved GPAT amino acid sequences as provided in SEQ ID NOs:225,
226, and 227, or a sequence of amino acids which is at least 50%,
preferably at least 60%, more preferably at least 65% identical
thereto.
[1359] In another embodiment, the nucleic acid molecule comprises a
sequence of nucleotides encoding a DGAT2. The sequence of
nucleotides may comprise i) a sequence of nucleotides selected from
any one of SEQ ID NO:204 to 211, ii) encode a polypeptide
comprising amino acids having a sequence as provided in any one of
SEQ ID NO:212 to 219, or a biologically active fragment thereof,
iii) be at least 50% identical to i) or ii), or iv) hybridize to
any one of i) to iii) under stringent conditions. In a preferred
embodiment, the DGAT2 comprises a sequence of nucleotides of SEQ ID
NO:204 and/or a sequence of nucleotides encoding a polypeptide
comprising amino acids having a sequence as provided in SEQ ID
NO:212.
[1360] A cell comprising a nucleic acid molecule encoding a fatty
acid acyltransferase operably linked to a promoter which is active
in the cell may be obtained using standard procedures in the art
such as by introducing the nucleic acid molecule into a cell by,
for example, calcium phosphate precipitation, polyethylene glycol
treatment, electroporation, and combinations of these treatments.
Other methods of cell transformation can also be used and include,
but are not limited to, the introduction of DNA into plants by
direct DNA transfer or injection. Transformed plant cells may also
be obtained using Agrobacterium-mediated transfer and acceleration
methods as described herein.
[1361] The method further comprises determining if the level of
MAG, DAG and/or TAG produced in the cell is increased when compared
to a corresponding cell lacking the nucleic acid using known
techniques in the art such as those exemplified in Example 1. For
instance, lipids can be extracted in a chloroform/methanol
solution, dried and separated by thin layer chromatography (TLC).
Identities of TAG, DAG, MAG, free fatty acid, and other lipids can
be verified with internal lipid standards after staining with
iodine vapor. The resultant chromatograms can analyzed using a
PhosphorImager and the amount of MAG, DAG and TAG quantified on the
basis of the known amount of internal standards, or alternatively,
the cells may be fed sn-2 monooleoylglycerol[.sup.14C] or
[.sup.14C]glycerol-3-phosphate and associated radioactivity
quantitated by liquid scintillation counting (i.e., the amount of
labelled MAG, DAG and TAG is quantified).
[1362] The method further comprises identifying a nucleic acid
molecule encoding a fatty acid acyltransferase having an increased
ability to produce MAG, DAG and/or TAG in a cell. In a preferred
embodiment, the fatty acid acyltransferase catalyzes an enzyme
reaction in the MGAT pathway. In a further preferred embodiment,
DAG is increased via the MGAT pathway (i.e., acylation of MAG with
fatty acyl-CoA is catalysed by a MGAT to form DAG). In another or
additional embodiment, the substrate MAG is produced by a GPAT
which also has phosphatase activity and/or DAG is acylated with
fatty acyl-CoA by a DGAT and/or a MGAT having DGAT activity to form
TAG.
Gloss
[1363] Certain aspects of the invention relate to measuring the
glossiness of vegetative material as a marker for the level of
lipid in the material, with higher glossiness levels being
associated with higher lipid levels.
[1364] The gloss of the vegetative material can be determined using
known procedures. Glossmeters (reflectometers) provide a
quantifiable way of measuring gloss intensity ensuring consistency
of measurement by defining the precise illumination and viewing
conditions. The configuration of both illumination source and
observation reception angles allows measurement over a small range
of the overall reflection angle. The measurement results of a
glossmeter are related to the amount of reflected light from a
black glass standard with a defined refractive index. The ratio of
reflected to incident light for the specimen, compared to the ratio
for the gloss standard, is recorded as gloss units.
[1365] The measurement scale, Gloss Units (GU), of a glossmeter is
a scaling based on a highly polished reference black glass standard
with a defined refractive index having a specular reflectance of
100GU at the specified angle. This standard is used to establish an
upper point calibration of 100 with the lower end point established
at 0 on a perfectly matt surface. This scaling is suitable for most
non-metallic materials.
[1366] The optimal or expected level of glossiness of vegetative
material is likely to vary between plant species. The skilled
person can readily analyse the lipid content of vegetative material
of different plants of the invention and identify a suitable
pre-determined level of glossiness that can be used as a standard
in the field for assessing the best time to havest a vegetative
material from a particular plant species.
EXAMPLES
Example 1. General Materials and Methods
Expression of Genes in Plant Cells in a Transient Expression
System
[1367] Genes were expressed in plant cells using a transient
expression system essentially as described by Voinnet et al. (2003)
and Wood et al. (2009). Binary vectors containing the coding region
to be expressed by a strong constitutive e35S promoter containing a
duplicated enhancer region were introduced into Agrobacterium
tumefaciens strain AGL1. A chimeric binary vector, 35S:p19, for
expression of the p19 viral silencing suppressor was separately
introduced into AGL1, as described in WO2010/057246. A chimeric
binary vector, 35S:V2, for expression of the V2 viral silencing
suppressor was separately introduced into AGL1. The recombinant
cells were grown to stationary phase at 28.degree. C. in LB broth
supplemented with 50 mg/L kanamycin and 50 mg/L rifampicin. The
bacteria were then pelleted by centrifugation at 5000 g for 5 min
at room temperature before being resuspended to OD600=1.0 in an
infiltration buffer containing 10 mM MES pH 5.7, 10 mM MgCl.sub.2
and 100 uM acetosyringone. The cells were then incubated at
28.degree. C. with shaking for 3 hours after which the OD600 was
measured and a volume of each culture, including the viral
suppressor construct 35S:p19 or 35S:V2, required to reach a final
concentration of OD600=0.125 added to a fresh tube. The final
volume was made up with the above buffer. Leaves were then
infiltrated with the culture mixture and the plants were typically
grown for a further three to five days after infiltration before
leaf discs were recovered for either purified cell lysate
preparation or total lipid isolation.
Purified Leaf Lysate Assay
[1368] Nicoliana benthamiana leaf tissues previously infiltrated as
described above were ground in a solution containing 0.1 M
potassium phosphate buffer (pH 7.2) and 0.33 M sucrose using a
glass homogenizer. Leaf homogenate was centrifuged at 20,000 g for
45 minutes at 4.degree. C. after which each supernatant was
collected. Protein content in each supernatant was measured
according to Bradford (1976) using a Wallac1420 multi-label counter
and a Bio-Rad Protein Assay dye reagent (Bio-Rad Laboratories,
Hercules, Calif. USA). Acyltransferase assays used 100 .mu.g
protein according to Cao et al. (2007) with some modifications. The
reaction medium contained 100 mM Tris-HCl (pH 7.0), 5 mM
MgCl.sub.2, 1 mg/mL BSA (fatty acid-free), 200 mM sucrose, 40 mM
cold oleoyl-CoA, 16.4 .mu.M sn-2 monooleoylglycerol[.sup.14C](55
mCi/mmol, American Radiochemicals, Saint Louis, Mo. USA) or 6.0
.mu.M [.sup.14C]glycerol-3-phosphate (G-3-P) disodium salt (150
mCi/mmol, American Radiochemicals). The assays were carried out for
7.5, 15, or 30 minutes.
Lipid Analysis
[1369] In summary, the methods used for analysing lipids in seeds
or vegetative tissues were as follows:
[1370] Arabidopsis Seed and any Other Similar Sized Seed:
[1371] (i) Fatty acid composition-direct methylation of fatty acids
in seeds, without crushing of seeds.
[1372] (ii) Total fatty acid or TAG quantitation--direct
methylation of fatty acids in seeds, without crushing of seeds,
with use of a 17:0 TAG standard.
[1373] Canola seed, Camelina seed, and any other larger sized
seeds:
[1374] (i) Single seed fatty acid composition--direct methylation
of fatty acids in seed after breaking seed coat.
[1375] (ii) Pooled seed-fatty acid composition of total extracted
lipid--crushing seeds in CHCl.sub.3/MeOH and methylation of
aliquots of the extracted lipid.
[1376] (iii) Pooled seed-total lipid content (seed oil
content)--two times lipid extraction for complete recovery of seed
lipids after crushing seeds from known amount of dessicated seeds,
with methylation of lipids from known amount of seeds together with
17:0 fatty acids as internal standard.
[1377] (iv) Pooled seed-purified TAG quantitation--two times lipid
extraction for complete recovery of seed lipids after crushing
seeds, from known amount of dessicated seeds, TAG fractionation
from the lipid using TLC, and direct methylation of TAG in silica
using 17:0 TAG as internal standard.
[1378] Leaf Samples:
[1379] (i) Fatty acid composition of total lipid--direct
methylation of fatty acids in freeze-dried samples.
[1380] (ii) Total lipid quantitation--direct methylation of fatty
acids in known weight of freeze-dried samples, with 17:0 FFA.
[1381] (iii) TAG quantitation--because of the presence of
substantial amounts of polar lipids in leaves, TAG was fractionated
by TLC from extracted total lipids, and methylated in the presence
of 17:0 TAG internal standard. Steps: Freeze dry samples, weighing,
lipid extraction, fractionation of TAG from known amount of total
lipids, direct methylation of TAG in silica together with 17:0 TAG
as internal standard.
[1382] The methods are detailed as follows:
[1383] Analysis of Oil Content in Ambidposis Seeds
[1384] Where seed oil content was to be determined in small seeds
such as Arabidopsis seeds, seeds were dried in a desiccator for 24
hours and approximately 4 mg of seed was transferred to a 2 ml
glass vial containing Teflon-lined screw cap. 0.05 mg
triheptadecanoin dissolved in 0.1 ml toluene was added to the vial
as internal standard. Seed FAME were prepared by adding 0.7 ml of
IN methanolic HCl (Supelco) to the vial containing seed material.
Crushing of the seeds was not necessary with small seeds such as
Arabidopsis seeds. The mixture was vortexed briefly and incubated
at 80.degree. C. for 2 hours. After cooling to room temperature,
0.3 ml of 0.9% NaCl (w/v) and 0.1 ml hexane was added to the vial
and mixed well for 10 minutes in a Heidolph Vibramax 110. The FAME
was collected into a 0.3 ml glass insert and analysed by GC with a
flame ionization detector (FID) as mentioned earlier.
[1385] The peak area of individual FAME were first corrected on the
basis of the peak area responses of a known amount of the same
FAMEs present in a commercial standard GLC-411 (NU-CHEK PREP, INC.,
USA). GLC-411 contains equal amounts of 31 fatty acids (% by
weight), ranging from C8:0 to C22:6. In case of fatty acids which
were not present in the standard, the peak area responses of the
most similar FAME was taken. For example, the peak area response of
FAMEs of 16:1d9 was used for 16:1d7 and the FAME response of C22:6
was used for C22:5. The corrected areas were used to calculate the
mass of each FAME in the sample by comparison to the internal
standard mass. Oil is stored mainly in the form of TAG and its
weight was calculated based on FAME weight. Total moles of glycerol
was determined by calculating moles of each FAME and dividing total
moles of FAMEs by three. TAG was calculated as the sum of glycerol
and fatty acyl moieties using a relation: % oil by
weight=100.times. ((41.times.total mol FAME/3)+(total g
FAME-(15.times.total mol FAME)))/g seed, where 41 and 15 are
molecular weights of glycerol moiety and methyl group,
respectively.
[1386] Analysis of Oil Content in Camelina Seeds and Canola Seeds
by Extraction
[1387] After harvest at plant maturity, Camelina or canola seeds
were dessicated by storing the seeds for 24 hours at room
temperature in a dessicator containing silica gel as dessicant.
Moisture content of the seeds is typically 6-8%. Total lipids were
extracted from known weights of the dessicated seeds by crushing
the seeds using a mixture of chloroform and methanol (2/1 v/v) in
an eppendorf tube using a Reicht tissue lyser (22 frequency/seconds
for 3 minutes) and a metal ball. One volume of 0.1M KCl was added
and the mixture shaken for 10 minutes. The lower non-polar phase
was collected after centrifuging the mixture for 5 minutes at 3000
rpm. The remaining upper (aqueous) phase was washed with 2 volumes
of chloroform by mixing for 10 minutes. The second non-polar phase
was also collected and pooled with the first. The solvent was
evaporated from the lipids in the extract under nitrogen flow and
the total dried lipid was dissolved in a known volume of
chloroform.
[1388] To measure the amount of lipid in the extracted material, a
known amount of 17:0-TAG was added as internal standard and the
lipids from the known amount of seeds incubated in 1 N
methanolic-HCl (Supelco) for 2 hours at 80.degree. C. FAME thus
made were extracted in hexane and analysed by GC. Individual FAMEs
were quantified on the basis of the amount of 17:0 TAG-FAME.
Individual FAMEs weights, after subtraction of weights of the
esterified methyl groups from FAME, were converted into moles by
dividing by molecular weights of individual FAMEs. Total moles of
all FAMEs were divided by three to calculate moles of TAG and
therefore glycerol. Then, moles of TAG were converted in to weight
of TAG. Finally, the percentage oil content on a seed weight basis
was calculated using seed weights, assuming that all of the
extracted lipid is TAG or equivalent to TAG for the purpose of
calculating oil content. This method was based on Li et al.,
(2006). Seeds other than Camelina or canola seeds that are of a
similar size can also be analysed by this method.
[1389] Canola and other seed oil content can also be measured by
nuclear magnetic resonance techniques (Rossell and Pritchard,
1991), for example, by a pulsed wave NMS 100 Minispec (Bruker Pty
Ltd Scientific Instruments, Germany), or by near infrared
reflectance spectroscopy such as using a NIRSystems Model 5000
monochromator. The NMR method can simultaneously measure moisture
content. Moisture content can also be measured on a sample from a
batch of seeds by drying the seeds in the sample for 18 hours at
about 100.degree. C., according to Li et al., (2006).
[1390] Where fatty acid composition is to be determined for the oil
in canola seed, the direct methylation method used for Arabidopsis
seed (above) can be used, modified with the addition of cracking of
the canola seedcoat. This method extracts sufficient oil from the
seed to allow fatty acid composition analysis.
Analysis of Lipids from Leaf Lysate Assays
[1391] Lipids from the lysate assays were extracted using
chloroform:methanol:0.1 M KCl (2:1:1) and recovered. The different
lipid classes in the samples were separated on Silica gel 60 thin
layer chromatography (TLC) plates (MERCK, Dennstadt, Germany)
impregnated with 10% boric acid. The solvent system used to
fractionate TAG from the lipid extract consisted of
chloroform/acetone (90/10 v/v). Individual lipid classes were
visualized by exposing the plates to iodine vapour and identified
by running parallel authentic standards on the same TLC plate. The
plates were exposed to phosphor imaging screens overnight and
analysed by a Fujifilm FLA-5000 phosphorimager before liquid
scintillation counting for DPM quantification.
Total Lipid Isolation and Fractionation
[1392] Tissues including leaf samples were freeze-dried, weighed
(dry weight) and total lipids extracted as described by Bligh and
Dyer (1959) or by using chloroform:methanol:0.1 M KCl (CMK; 2:1:1)
as a solvent. Total lipids were extracted from N. benthamiana leaf
samples, after freeze dying, by adding 900 .mu.L of a
chloroform/methanol (2/1 v/v) mixture per 1 cm diameter leaf
sample. 0.8 .mu.g DAGE was added per 0.5 mg dry leaf weight as
internal standard when TLC-FID analysis was to be performed.
Samples were homogenized using an IKA ultra-turrax tissue lyser
after which 500 .mu.L 0.1 M KCl was added. Samples were vortexed,
centrifuged for 5 min and the lower phase was collected. The
remaining upper phase was extracted a second time by adding 600
.mu.L chloroform, vortexing and centrifuging for 5 min. The lower
phase was recovered and pooled into the previous collection. Lipids
were dried under a nitrogen flow and resuspended in 2 .mu.L
chloroform per mg leaf dry weight. Total lipids of N. tabacum
leaves or leaf samples were extracted as above with some
modifications. If 4 or 6 leaf discs (each approx 1 cm.sup.2 surface
area) were combined, 1.6 ml of CMK solvent was used, whereas if 3
or less leaf discs were combined, 1.2 ml CMK was used. Freeze dried
leaf tissues were homogenized in an eppendorf tube containing a
metallic ball using a Reicht tissue lyser (Qiagen) for 3 minutes at
20 frequency/sec.
Separation of Neutral Lipids Via TLC and Transmethylation
[1393] Known volumes of total leaf extracts such as, for example,
30 .mu.L, were loaded on a TLC silica gel 60 plate (1.times.20 cm)
(Merck KGaA, Germany). The neutral lipids were separated via TLC in
an equilibrated development tank containing a hexane/DEE/acetic
acid (70/30/1 v/v/v/) solvent system. The TAG bands were visualised
by iodine vapour, scraped from the TLC plate, transferred to 2 mL
GC vials and dried with N.sub.2. 750 .mu.L of IN methanolic-HCl
(Supelco analytical, USA) was added to each vial together with a
known amount of C17:0 TAG, such as, for example, 30 .mu.g, as
internal standard for quantification.
[1394] When analysing the effect on oleic acid levels of specific
gene combinations, TAG and polar lipids bands were collected from
the TLC plates. Next, 15 .mu.g of C17:0 internal standard was added
to samples such as TAG samples, polar lipid samples and 20 .mu.L of
the total lipid extracts. Following drying under N.sub.2, 70 .mu.L
toluene and 700 .mu.L methanolic HCl were added.
[1395] Lipid samples for fatty acid composition analysis by GC were
transmethylated by incubating the mixtures at 80.degree. C. for 2
hours in the presence of the methanolic-HCl. After cooling samples
to room temperature, the reaction was stopped by adding 350 .mu.l
H.sub.2O. Fatty acyl methyl esters (FAME) were extracted from the
mixture by adding 350 .mu.l hexane, vortexing and centrifugation at
1700 rpm for 5 min. The upper hexane phase was collected and
transferred into GC vials with 300 .mu.l conical inserts. After
evaporation, the samples were resuspended in 30 .mu.l hexane. One
p1 was injected into the GC.
[1396] The amount of individual and total fatty acids (TFA) present
in the lipid fractions was quantified by GC by determining the area
under each peak and calculated by comparison with the peak area for
the known amount of internal standard. TAG content in leaf was
calculated as the sum of glycerol and fatty acyl moieties in the
TAG fraction using a relation: % TAG by weigh=100.times.
((41.times.total mol FAME/3)+(total g FAME-(15.times.total mol
FAME)))/g leaf dry weight, where 41 and 15 are molecular weights of
glycerol moiety and methyl group, respectively.
Capillary Gas-Liquid Chromatography (GC)
[1397] FAME were analysed by GC using an Agilent Technologies 7890A
GC (Palo Alto, Calif., USA) equipped with an SGE BPX70 (70%
cyanopropyl polysilphenylene-siloxane) column (30 m.times.0.25 mm
i.d., 0.25 .mu.m film thickness), an FID, a split/splitless
injector and an Agilent Technologies 7693 Series auto sampler and
injector. Helium was used as the carrier gas. Samples were injected
in split mode (50:1 ratio) at an oven temperature of 150.degree. C.
After injection, the oven temperature was held at 150.degree. C.
for 1 min, then raised to 210.degree. C. at 3.degree. C.min.sup.-1
and finally to 240.degree. C. at 50.degree. C.min.sup.-1. Peaks
were quantified with Agilent Technologies ChemStation software (Rev
B.04.03 (16), Palo Alto, Calif., USA) based on the response of the
known amount of the external standard GLC-411 (Nucheck) and
C17:0-Me internal standard.
Quantification of TAG via Iatroscan
[1398] One .mu.L of lipid extract was loaded on one Chromarod-SII
for TLC-FID Iatroscan.TM. (Mitsubishi Chemical Medience
Corporation--Japan). The Chromarod rack was then transferred into
an equilibrated developing tank containing 70 mL of a
hexane/CHCl.sub.3/2-propanol/formic acid (85/10.716/0.567/0.0567
v/v/v/v) solvent system. After 30 min of incubation, the Chromarod
rack was dried for 3 min at 100.degree. C. and immediately scanned
on an latroscan MK-6s TLC-FID analyser (Mitsubishi Chemical
Medience Corporation--Japan). Peak areas of DAGE internal standard
and TAG were integrated using SIC-480II integration software
(Version:7.0-E SIC System instruments Co., LTD--Japan).
[1399] TAG quantification was carried out in two steps. First, DAGE
was scanned in all samples to correct the extraction yields after
which concentrated TAG samples were selected and diluted. Next, TAG
was quantified in diluted samples with a second scan according to
the external calibration using glyceryl trilinoleate as external
standard (Sigma-Aldrich).
Quantification of TAG in Leaf Samples by GC
[1400] The peak area of individual FAME were first corrected on the
basis of the peak area responses of known amounts of the same FAMEs
present in a commercial standard GLC-411 (NU-CHEK PREP, Inc., USA).
The corrected areas were used to calculate the mass of each FAME in
the sample by comparison to the internal standard. Since oil is
stored primarily in the form of TAG, the amount of oil was
calculated based on the amount of FAME in each sample. Total moles
of glycerol were determined by calculating the number of moles of
FAMEs and dividing total moles of FAMEs by three. The amount of TAG
was calculated as the sum of glycerol and fatty acyl moieties using
the formula: % oil by weight=100.times. ((41.times.total mol
FAME/3)+(total g FAME-(15.times.total mol FAME)))/g leaf dry
weight, where 41 and 15 were the molecular weights of glycerol
moiety and methyl group, respectively.
DGAT assay in Saccharomyces cerevisiae H1246
[1401] Saccharomyces cerevisiae strain H1246 is completely devoid
of DGAT activity and lacks TAG and sterol esters as a result of
knockout mutations in four genes (DGA1, LRO1, ARE1, ARE2). The
addition of free fatty acid (e.g. 1 mM 18:1.sup..DELTA.9) to H1246
growth media is toxic in the absence of DGAT activity. Growth on
such media can therefore be used as an indicator or selection for
the presence of DGAT activity in this yeast strain.
[1402] S cerevisiae H1246 was transformed with the pYES2 construct
(negative control), a construct encoding Arabidopsis thaliana DGAT1
in pYES2, or a construct encoding Mus musculus MGAT2 in pYES2.
Transformants were fed [.sup.14C]18:1.sup..DELTA.9 free fatty
acids.
[1403] In a separate experiment, S cerevisiae H1246 was transformed
with the pYES2 construct (negative control), a construct encoding
Bernadia pulchella DGAT1 in pYES2, or a construct encoding M.
musculus MGAT1 in pYES2 and fed 18:1.sup..DELTA.9 free fatty acids.
S. cerevisiae S288C wild type strain transformed with pYES2 served
as a positive control.
[1404] Yeast transformants were resuspended in sterile mQ water and
diluted to OD600=1. Samples were further diluted in four
consecutive dilutions, each at 1/10. 2 .mu.l of each dilution was
spotted on each of the plates (YNBD, YNBG, YNBG+FA) together with 2
.mu.L mQ water and 2 .mu.L of an untransformed H1246 cell
suspension (OD600=1). Plates were incubated for 6 days at
30.degree. C. before scoring growth.
Plate Medium, 40 mL Media Per Plate
[1405] YNBD: minimal dropout medium lacking uracil and containing
2% glucose, 0.01% NP40 and 100 .mu.L ethanol. [1406] YNBG: minimal
dropout medium lacking uracil and containing 2% galactose, 1%
raffinose, 0.01% NP40 and 100 .mu.L ethanol. [1407] YNBG+FA:
minimal dropout medium lacking uracil and containing 2% galactose,
1% raffinose, 0.01% NP40 and 1 mM C18:1.sup..DELTA.9 dissolved in
100 .mu.l ethanol.
Example 2. Constitutive Expression of a Monoacylglycerol
Acyltransferase in PLANT CELLS
MGAT1
[1408] The enzyme activity of the monoacylglycerol acyltransferase
1 (MGAT1) encoded by the gene from M. musculus (Yen et al., 2002)
and A. thaliana diacylglycerol acyltransferase (DGAT1)
(Bouvier-Nave et al., 2000), used here as a comparison with MGAT1,
were demonstrated in N. benthamiana leaf tissue using a transient
expression system as described in Example 1.
[1409] A vector designated 35S-pORE04 was made by inserting a PstI
fragment containing a 35S promoter into the SfoI site of vector
pORE04 after T4 DNA polymerase treatment to blunt the ends (Coutu
et al., 2007). A chimeric DNA encoding the M. musculus MGAT1,
codon-optimised for Brassica napus, was synthesized by Geneart and
designated 0954364_MGAT_pMA. A chimeric DNA designated 35S:MGAT1
and encoding the M. musculus MGAT1 (Genbank Accession No. Q91ZV4)
for expression in plant cells was made by inserting the entire
coding region of 0954364_MGAT_pMA, contained within an EcoRI
fragment, into 35S-pORE04 at the EcoRI site. The vector containing
the 35S:MGAT1 construct was designated as pJP3184. Similarly, a
chimeric DNA 35S:DGAT1 encoding the A. thaliana DGAT1 (Genbank
Accession No. AAF19262) for expression in plant cells was made by
inserting the entire coding region of pXZP513E, contained within a
BamHI-EcoRV fragment, into 35S-pORE04 at the BamHI-EcoRV site. The
vector containing the 35S:DGAT1 construct was designated
pJP2078.
[1410] The chimeric vectors were introduced into A. tumefaciens
strain AGL1 and cells from cultures of these infiltrated into leaf
tissue of N. benthamiana plants in a 24.degree. C. growth room. In
order to allow direct comparisons between samples and to reduce
inter-leaf variation, samples being compared were infiltrated on
either side of the same leaf. Experiments were performed in
triplicate. Following infiltration, the plants were grown for a
further three days before leaf discs were taken, freeze-dried, and
lipids extracted from the samples were fractionated and quantified
as described in Example 1. This analysis revealed that the MGAT1
and DGAT1 genes were functioning to increase leaf oil levels in N.
benthamiana as follows.
[1411] Leaf tissue transformed with the 35S:p19 construct only
(negative control) contained an average of 4 .mu.g free fatty acid
(FFA) derived from DAG/mg dry leaf weight and 5 .mu.g FFA derived
from TAG/mg dry leaf weight. Leaf tissue transformed with the
35S:p19 and 35S:DGAT1 constructs (control for expression of DGAT1)
contained an average of 4 .mu.g FFA derived from DAG/mg dry leaf
weight and 22 .mu.g FFA derived from TAG/mg dry leaf weight. Leaf
tissue transformed with the 35S:p19 and 35S:MGAT1 constructs
contained an average of 8 .mu.g FFA derived from DAG/mg dry leaf
weight and 44 .mu.g FFA derived from TAG/mg dry leaf weight. Leaf
tissue transformed with the 35S:p19, 35S:DGAT1 and 35S:MGAT1
constructs did not contain DAG or TAG levels higher than those
observed in the 35S:p19 and 35S:MGAT1 infiltration (FIG. 2). Also,
a decrease in the level of saturates in seeds was noted after MGAT
expression when compared with either the p19 control or DGAT1
samples (Table 2).
[1412] The data described above demonstrated that the MGAT1 enzyme
was far more active than the DGAT1 enzyme in promoting both DAG and
TAG accumulation in leaf tissue. Expression of the MGAT1 gene
resulted in twice as much TAG and DAG accumulation in leaf tissue
compared to when the DGAT1 was expressed. This result was highly
surprising and unexpected, considering that the MGAT is an enzyme
expressed in mouse intestine, a vastly different biological system
than plant leaves. This study was the first demonstration of
ectopic MGAT expression in a plant cell.
[1413] Leaf samples infiltrated with M. musculus MGAT1 accumulated
double the DAG and TAG relative to leaf tissue infiltrated with A.
thaliana DGAT1 alone. The efficiency of the production of TAG was
also surprising and unexpected given that the mouse MGAT has only
very low activity as a DGAT. Leaf tissue infiltrated with genes
encoding both MGAT1 and DGAT1 did not accumulate significantly more
TAG than the MGAT1-only leaf sample. FIG. 1 is a representation of
various TAG accumulation pathways, most of which converge at DAG, a
central molecule in lipid synthesis. For instance, MAG, DAG and TAG
can be inter-converted via various enzyme activities including
transacylation, lipase, MGAT, DGAT and PDAT. A decrease in the
level of saturates was also noted after MGAT expression.
MGAT2
[1414] A chimeric DNA designated 35S:MGAT2 and encoding the M.
musculus MGAT2 for expression in plant cells was made by inserting
the entire MGAT2 coding region, contained within an EcoRI fragment,
into 35S-pORE04 at the EcoRI site. The enzyme activity of the
monoacylglycerol acyltransferase 2 (MGAT2) encoded by the gene from
M. musculus (Yen, 2003) (Genbank Accession No. Q80W94) and A.
thaliana DGAT1 (Bouvier-Nave et al., 2000), used here as a
comparison with MGAT2, was also demonstrated in N. benthamiana leaf
tissue using a transient expression system as described in Example
1.
[1415] Compared with controls, DGAT1 expression increased leaf TAG
5.9-fold, MGAT2 by 7.3-fold and the combination of MGAT2+DGAT1 by
9.8-fold (FIG. 3). The ability of MGAT2 alone to yield such
significant increases in TAG was unexpected for a number of
reasons. Firstly, the amount of substrate MAG present in leaf
tissue is known to be low and large increases in TAG accumulation
from this substrate would not be expected. Secondly, the addition
of MGAT activity alone (i.e., addition of MGAT2 which does not have
DGAT activity) would be expected to yield DAG, not TAG, especially
in a leaf environment where little native DGAT activity is usually
present.
Discussion
[1416] The present inventors have surprisingly demonstrated that
the transgenic expression of a MGAT gene results in significant
increases in lipid yield in plant cells. The present inventors
understand that Tumaney et al. had isolated a DGAT with some MGAT
activity and that they were not successful in attempts to clone a
gene encoding a MGAT as defined herein. Tumaney et al. (2001)
reported MGAT activity in peanut and isolated an enzyme responsible
for this activity. However, Tumaney et al. did not publish results
of tests for DGAT activity and it therefore seems that the enzyme
reported was a DGAT with some MGAT activity. Indeed, previous work
had failed to identify any MGAT activity in other species (Stobart
et al., 1997). Furthermore, it was surprising that the enzyme
isolated by Tumaney et al. was a soluble, cytosolic, enzyme rather
than a membrane-bound enzyme.
[1417] Recently, researchers have identified a microsomal
membrane-bound monoacylglycerol acyltransferase (MGAT) from
immature peanut (Arachis hypogaea) seeds. The MGAT could be
solubilized from microsomal membranes using a combination of a
chaotropic agent and a zwitterionic detergent, and a functionally
active 14S multiprotein complex was isolated and characterized.
Oleosin3 (OLE3) was identified as part of the multiprotein complex,
which is capable of performing bifunctional activities such as
acylating monoacylglycerol (MAG) to diacylglycerol (DAG) and
phospholipase A2 (PLA2; Parthibane et al., 2012).
Example 3. Biochemical Demonstration of Transgenic MGAT Activity in
Leaf Extracts
[1418] Cell lysates were made from N. benthamiana leaf tissue that
had been infiltrated with 35S:MGAT1, 35S:MGAT2 and 35S:DGAT1, as
described in Example 1. Separate leaf infiltrations were performed,
each in triplicate, for strains containing the 35S:p19 construct
only (negative control), the 35S:MGAT2 strain together with the
35S:p19 strain, and a mixture of the 35S:MGAT2 and 35S:DGAT1
Agrobacterium strains with the 35S:p19 strain. The triplicate
samples were harvested after three days and a purified cell lysate
prepared by mechanical tissue lysis and centrifugation. The MGAT
activities of the purified cell lysates were compared by feeding
[.sup.14C]MAG to the lysates as described in Example 1. The data
are shown in FIG. 4.
[1419] Little MGAT activity was observed in the 35S:p19 control
sample, since most of the radioactivity remained in MAG throughout
the assay. In contrast, the majority of the labelled MAG in the
35S:MGAT2 sample was rapidly converted to DAG (FIG. 4, central
panel), indicating strong MGAT activity expressed from the
35S:MGAT2 construct. Furthermore, a significant amount of TAG was
also produced. The TAG production observed in the 35S:MGAT2 sample
was likely due to native N. benthamiana DGAT activity, or produced
by another TAG synthesis route. The amount of TAG production was
greatly increased by the further addition of 35S:DGAT1 (FIG. 4,
right hand panel), indicating that the MGAT2 enzyme produced DAG
which was accessible for conversion to TAG by DGAT1 in plant
vegetative tissues.
Example 4. Biochemical Demonstration of the Production of
MGAT-Accessible MAG in Leaf Extracts
[1420] In the in vitro assays described in Example 3 using leaf
lysates, the substrates (sn-2 MAG and oleoyl-CoA) were exogenously
supplied, whereas in vivo MGAT activity in intact plant tissues
would require the native presence of these substrates.
[1421] The presence of low levels of MAG is various plant tissues
has been reported previously (Hirayama and Hujii, 1965; Panekina et
al., 1978; Lakshminarayana et al., 1984; Perry & Harwood,
1993). To test whether the MGAT2 could access MAG produced by
native plant pathways, the above experiment was repeated but this
time feeding [.sup.14C]G-3-P to the lysates. The resultant data are
shown schematically in FIG. 5.
[1422] The production of labelled MAG was observed in all samples,
indicating the de novo production of MAG from the G-3-P in plant
leaf lysates. Labelled DAG and TAG products were also observed in
all samples although these were relatively low in the 35S:p19
control sample, indicating that the production of these neutral
lipids by the endogenous Kennedy pathway was relatively low in this
sample. In contrast, the majority of the label in the MGAT2 and
MGAT2+DGAT1 samples appeared in the DAG and TAG pools, indicating
that the exogenously added MGAT catalysed conversion of the MAG
that had been produced from the labelled G-3-P by a native plant
pathway.
[1423] Examples 2 to 4 demonstrate several key points: 1) Leaf
tissue can synthesise MAG from G-3-P such that the MAG is
accessible to an exogenous MGAT expressed in the leaf tissue; 2)
Even an MGAT which is derived from mammalian intestine can function
in plant tissues, not known to possess an endogenous MGAT,
requiring a successful interaction with other plant factors
involved in lipid synthesis; 3) DAG produced by the exogenous MGAT
activity is accessible to a plant DGAT, or an exogenous DGAT, to
produce TAG; and 4) the expression of an exogenous MGAT can yield
greatly increased TAG levels in plant tissues, levels which are at
least as great as that yielded by exogenous A. thaliana DGAT1
expression.
Example 5. Expression of DGAT1, MGAT1 and MGAT2 in Yeast
[1424] Chimeric yeast expression vectors were constructed by
inserting genes encoding the A. thaliana DGAT1, M. musculus MGAT1
and M. musculus MGAT2 into the pYES2 vector to yield pYES2:DGAT1,
pYES2:MGAT1 and pYES2:MGAT2. These constructs were transformed in
Saccharomyces cerevisiae strain H1246 which is completely devoid of
DGAT activity and lacks TAG and sterol esters as a result of
knockout mutations in four genes (DGA1, LRO1, ARE1, ARE2). Yeast
strain H1246 is capable of synthesizing DAG from exogenously added
fatty acids, but is unable to convert the DAG to TAG because of the
knockout mutations. The transformed yeast cultures were fed
[.sup.14C]18:1.sup..DELTA.9 before total lipids were extracted and
fractionated by TLC as described in Example 1. An autoradiogram of
a representative TLC plate is shown in FIG. 6.
[1425] TAG formation, indicating the presence of DGAT activity, was
observed for the yeast cells containing either DGAT1 (positive
control) and the mammalian MGAT1, but not in cells containing the
MGAT2 encoded by the native M. musculus coding region. It was
concluded that MGAT1 from mouse also had DGAT activity in yeast
cells, and therefore functioned as a dual function MGAT/DGAT
enzyme, whereas MGAT2 did not have detectable DGAT activity and was
therefore solely an MGAT. A construct which included an MGAT2
coding region which was codon optimization for expression in yeast
exhibited MGAT activity (production of DAG) when tested in vitro
using yeast microsomes and labelled MAG substrate, whereas a
similar construct which was codon-optimised for expression in B.
napus did not show DAG production in the yeast microsomes. This
experiment showed the benefit of codon-optimisation for the
organism in which heterologous coding regions were to be
expressed.
Example 6. Expression of a Monoacylglycerol Acyltransferase in
Plant, Seeds and Fungi
[1426] Expression of MGAT1 in Arabidopsis thaliana seeds
[1427] A gene encoding M. musculus MGAT1 and under the control of a
seed-specific promoter (FP1, a truncated Brassica napus napin
promoter) was used to generate stably transformed A. thaliana
plants and progeny seeds. The vector designated pJP3174 was made by
inserting a SalI fragment containing an EcoRI site flanked by the
FP1 promoter and Glycine max lectin polyadenylation signal into the
SalI-XhoI site of vector pCW141. The pCW141 vector also contained
an FP1-driven, intron-interrupted, seed-secreted GFP as a
screenable marker gene. The chimeric gene designated FP1:MGAT1-GFP
was made by inserting the entire coding region of the construct
0954364_MGAT_pMA, contained within an EcoRI fragment, into pJP3174
at the EcoRI site, generating pJP3179. This chimeric vector was
introduced into A. tumefaciens strain AGL1 and cells from culture
of the transformed Agrobacterium used to treat A. thaliana (ecotype
Columbia) plants using the floral dip method for transformation
(Clough and Bent, 1998). After maturation, the seeds from the
treated plants were viewed under a Leica MZFLIII dissection
microscope and ebq 100 mercury lamp. Fifteen transgenic seeds
(strongly GFP positive) and fifteen non-transgenic (GFP negative)
seeds were isolated and each set pooled. The GFP positive and GFP
negative pools were analysed for total fatty acid content as
described in Example 1. This analysis provided the average fatty
acid content and composition for seeds transformed with the MGAT
construct, but in a population which may have contained both
hemizygous and homozygous transformed seeds.
[1428] This analysis revealed that the MGAT1 gene was functioning
to increase seed oil levels in A. thaliana seed with the fifteen
non-transgenic seeds (control, the same as wild-type) containing an
average of 69.4 .mu.g total fatty acids while the fifteen
transgenic seeds transformed with the GFP gene, and therefore
likely to contain the FP1:MGAT1 genetic construct, contained an
average of 71.9 .mu.g total fatty acids. This was an increase of
3.5% in the oil content relative to the control (wild-type). The
analysis also revealed that the MGAT gene was functioning to enrich
polyunsaturated fatty acids in the seed, as seen from the fatty
acid composition of the total extracted lipid obtained from the
seeds. In particular, the amount of ALA present as a percentage of
the total fatty acid extracted from the seeds increasing from 16.0
to 19.6%. Similarly, the percentage of the fatty acid 20:2n6
increased from 1.25% to 1.90% and the fatty acid 20:3n3 increased
from 0.26% to 0.51% (Table 2).
TABLE-US-00003 TABLE 2 Effect of MGAT expression on seed fatty acid
composition. FA profile (% of TFA) Sample 16:00 16:01 16:3w3 C18:0
C18:1d9 C18:1d11 C18:2 C18:3 Control 7.41 0.36 0.12 3.00 15.26 1.98
30.93 15.98 MGAT1 7.11 0.32 0.11 2.95 13.86 1.51 28.87 19.59 Sample
C:20:0 20:1d11 20:1iso 20:2n6 20:3n3 C22:0 C22:1 C24:0 24:1d15
Total Control 1.86 17.95 1.74 1.25 0.26 0.57 0.98 0.20 0.17 100.00
MGAT1 1.90 17.22 1.71 1.90 0.51 0.57 1.52 0.19 0.17 100.00
[1429] A further experiment was performed where the FP1:MGAT1-GFP
chimeric DNA was modified to remove the GFP gene. This genetic
construct, designated FP1:MGAT1, was transformed into an A.
thaliana line which was mutant for FAD2. The total fatty acid
content of the T.sub.2 seed from antibiotic resistant T.sub.1
plants, as well as parental lines grown alongside these plants, was
determined according to Example 1. The data is shown in Table 3.
The average total fatty acids of the seed from the control lines
was 347.9 .mu.g/100 seeds whereas the average of the transgenic
seeds was 381.0 .mu.g/100 seeds. When the data for the control line
C6 was excluded for determining the average, the average for the
controls was 370 .mu.g/100 seeds. The oil content in the transgenic
seeds represented an increase of about 3% in relative terms
compared to the oil content in the untransformed seeds.
TABLE-US-00004 TABLE 3 Arabidopsis thaliana T.sub.2 FP1:MGAT1
transgenic and parental control seed fatty acid profiles and total
fatty acid quantification. .mu.g FA/100 Sample C16:0 C16:1 C18:0
C18:1 C18:1d11 C18:2 C18:3 C20:0 20:1d11 C22:0 C24:0 24:1d15 seeds
C7 6.2 0.5 2.5 81.3 4.2 0.6 2.7 0.7 0.7 0.3 0.2 0.1 442.5 C4 6.3
0.4 2.4 81.7 3.9 0.5 2.5 0.9 0.6 0.4 0.2 0.1 403.8 C8 6.4 0.5 2.6
81.1 4.1 0.6 2.6 0.8 0.6 0.4 0.2 0.1 403.2 C2 6.2 0.5 2.4 81.4 4.1
0.6 2.7 0.8 0.6 0.4 0.2 0.1 377.0 C1 6.4 0.5 2.4 80.6 4.1 0.7 3.3
0.8 0.6 0.4 0.2 0.1 344.8 C3 6.4 0.5 2.6 80.0 4.1 0.6 3.5 0.8 0.6
0.4 0.2 0.2 314.3 C5 6.3 0.5 2.6 80.7 4.4 0.6 2.4 0.7 0.6 0.9 0.2
0.1 310.6 C6 6.7 0.7 2.7 77.2 5.0 0.8 4.3 0.9 0.7 0.4 0.3 0.2 186.8
M23 5.9 0.4 2.0 81.4 5.0 0.8 2.4 0.7 0.7 0.5 0.2 0.2 455.7 M10 6.0
0.4 2.4 82.3 4.2 0.7 2.2 0.7 0.6 0.3 0.2 0.1 437.7 M22 5.9 0.4 2.2
81.4 4.8 0.8 2.4 0.7 0.6 0.4 0.2 0.2 425.0 M25 6.0 0.4 2.2 81.7 4.6
0.7 2.4 0.8 0.6 0.3 0.2 0.1 406.7 M8 6.0 0.4 2.2 81.6 4.5 0.8 2.5
0.7 0.6 0.3 0.2 0.2 404.5 M14 5.7 0.4 2.1 81.8 4.6 0.8 2.5 0.7 0.6
0.3 0.2 0.2 396.4 M26 6.2 0.4 2.2 81.8 4.4 0.8 2.2 0.7 0.6 0.4 0.2
0.1 393.0 M6 5.9 0.4 2.2 81.8 4.5 0.8 2.4 0.7 0.6 0.3 0.2 0.2 392.9
M5 5.9 0.5 2.2 80.9 4.8 0.9 2.6 0.7 0.7 0.5 0.2 0.2 389.7 M17 6.3
0.4 2.3 75.1 4.7 4.8 4.4 0.7 0.6 0.3 0.2 0.1 388.4 M9 6.1 0.4 2.3
81.8 4.4 0.7 2.4 0.7 0.6 0.3 0.2 0.1 388.2 M20 6.2 0.4 2.2 81.5 4.7
0.7 2.3 0.7 0.6 0.3 0.2 0.1 379.1 M12 6.2 0.4 2.2 81.6 4.4 1.0 2.2
0.7 0.6 0.3 0.2 0.1 374.7 M18 6.2 0.4 2.4 81.3 4.7 0.7 2.3 0.8 0.5
0.3 0.2 0.1 369.1 M24 6.1 0.4 2.2 81.6 4.6 0.7 2.3 0.9 0.6 0.3 0.2
0.1 361.7 M7 5.9 0.4 2.3 81.9 4.5 0.7 2.3 0.7 0.6 0.3 0.2 0.1 359.4
M4 6.2 0.4 2.4 81.3 4.4 0.7 2.5 0.8 0.5 0.3 0.2 0.2 352.3 M13 6.1
0.4 2.3 81.4 4.5 0.8 2.4 0.7 0.6 0.3 0.2 0.1 352.0 M16 6.1 0.4 2.2
81.8 4.4 0.7 2.4 0.7 0.6 0.3 0.2 0.2 340.5 M19 6.1 0.4 2.3 80.9 4.9
0.8 2.7 0.7 0.5 0.3 0.2 0.1 318.6 M3 6.0 0.5 2.3 81.1 4.7 0.9 2.7
0.7 0.6 0.3 0.2 0.2 316.6
[1430] The coding region of the mouse MGAT2 gene, codon-optimised
for expression in plant cells, was substituted for the MGAT1 coding
region in the constructs mentioned above, and introduced into
Arabidopsis. Thirty plants of each transgenic line (T1 and T2
plants, giving rise to T2- and T3-generation seeds) were grown in
the greenhouse in a randomly arranged distribution and compared to
control plants. Seeds from the transgenic plants were increased in
their oil content relative to the control seeds (FIG. 7). The
average TAG percentage of the T3 transgenic seeds represented a
relative increase of about 8% compared to the TAG percentage in the
untransformed seeds (Table 4). A significant increase was observed
in the level of polyunsaturated fatty acids in the TAG of the
transgenic seeds, in particular of ALA, and a decrease in saturated
fatty acid levels such as palmitic and stearic acids. Moreover, the
increased TAG levels and altered fatty acid composition was more
pronounced in the T3 generation than in the T2 seeds, presumably
due to the homozygous state of the transgene in the T3 seeds.
TABLE-US-00005 TABLE 4 TAG levels and fatty acid composition in TAG
extracted from Arabidopsis thaliana T2 and T3 seeds expressing
MGAT2 compared to untransformed control seed. C14:0 C16:0 C16:1
C18:0 C18:1d9 C18:1d11 C18:2 C18:3 Control 0.1 8.1 0.3 3.3 13.2 1.8
28.4 20.0 T2 seeds 0.1 7.2 0.2 2.8 13.0 1.3 27.9 24.3 T3 seeds 0.1
6.1 0.2 2.5 12.3 1.2 28.4 26.7 % TAG by C20:0 C20:1 20:1iso 20:2n6
C22:1 C24:0 24:1 Seed weight 2.2 17.2 1.9 1.8 1.2 0.3 0.2 32.4 1.6
14.8 3.1 1.8 1.2 0.3 0.2 37.9 1.8 15.3 1.5 1.9 1.5 0.4 0.2 40.2
Expression of MGAT1 in Brassica napus Seeds
[1431] The vector FP1:MGAT1 used for the expression of M. musculus
MGAT1 in Arabidopsis thaliana seeds was used to generate
transformed B. napus plants. The vector was introduced into A.
tumefaciens strain AGL1 via standard electroporation procedures.
Cultures were grown overnight at 28.degree. C. in LB medium with
agitation at 150 rpm. The bacterial cells were collected by
centrifugation at 4000 rpm for 5 minutes, washed with Winans' AB
(Winans, 1988) and re-suspended in 10 mL of Winans' AB medium (pH
5.2) and grown with kanamycin (50 mg/L) and rifampicin (25 mg/L)
overnight with the addition of 100 .mu.M acetosyringone. Two hours
before infection of the Brassica cells, spermidine (120 mg/L) was
added and the final density of the bacteria adjusted to an OD 600
nm of 0.3-0.4 with fresh AB media. Freshly isolated cotyledonary
petioles from 8-day old B. napus seedlings grown on 1/2 MS
(Murashige-Skoog, 1962) or hypocotyl segments preconditioned by 3-4
days on MS media with 1 mg/L thidiazuron (TDZ)+0.1 mg/L
alpha-naphthaleneacetic acid (NAA) were infected with 10 mL
Agrobacterium cultures for 5 minutes. Explants (cotyledonary
petiole and hypocotyl) infected with Agrobacterium were then
blotted on sterile filter paper to remove the excess Agrobacterium
and transferred to co-cultivation media (MS media with 1 mg/L
TDZ+0.1 mg/L NAA+100 .mu.M acetosyringone) supplemented with or
without different antioxidants (L-cysteine 50 mg/L and ascorbic 15
mg/L). All the plates were sealed with parafilm and incubated in
the dark at 23-24.degree. C. for 48 hours.
[1432] The co-cultivated explants (cotyledonary petiole and
hypocotyl) were then washed with sterile distilled water+500 mg/L
cefotaxime+50 mg/L timentin for 10 minutes, rinsed in sterile
distilled water for 10 minutes, blotted dry on sterile filter
paper, transferred to pre-selection media (MS+1 mg/L TDZ+0.1 mg/L
NAA+20 mg/L adenine sulphate (ADS)+1.5 mg/L AgNO.sub.3+250 mg/L
cefotaxime and 50 mg/L timentin) and cultured for five days at
24.degree. C. with a 16 hour/8 hour photoperiod. They were then
transferred to selection media (MS+1 mg/L TDZ+0.1 mg/L NAA+20 mg/L
ADS+1.5 mg/L AgNO.sub.3+250 mg/L cefotaxime and 50 mg/L timentin)
with 1.5 mg/L glufosinate ammonium and cultured for 4 weeks at
24.degree. C. with 16 hour/8 hour photoperiod with a biweekly
subculture onto the same media. Explants with green callus were
transferred to shoot initiation media (MS+1 mg/L kinetin+20 mg/L
ADS+1.5 mg/L AgNO.sub.3+250 mg/L cefotaxime+50 mg/L timentin+1.5
mg/L glufosinate ammonium) and cultured for another 2-3 weeks.
Shoots emerging form the resistant explants were transferred to
shoot elongation media (MS media with 0.1 mg/L gibberelic acid+20
mg/L ADS+1.5 mg/L AgNO.sub.3+250 mg/L ceftoxime+1.5 mg/L
glufosinate ammonium and cultured for another two weeks. Healthy
shoots 2-3 cm long were selected and transferred to rooting media
(1/2 MS with 1 mg/L NAA+20 mg/L ADS+1.5 mg/L AgNO.sub.3+250 mg/L
cefotaxime) and cultured for 2-3 weeks. Well established shoots
with roots were transferred to pots (seedling raising mix) and
grown in a growth cabinet for two weeks and subsequently
transferred to glasshouse. Sixteen individual transformants in the
cultivar Oscar were confirmed to be transgenic for the FP1:MGAT1
construct and grew normally under glasshouse conditions. Plant
growth appeared normal and the plants were fertile, flowering and
setting seed normally. The plants were grown to maturity and seeds
obtained from transformed plants were harvested. Seeds from some of
the transformed plants were analysed for seed oil content and fatty
acid composition. Data from these preliminary analyses showed
variability in the oil content and fatty acid composition, probably
due to the plants being grown at different times and under
different environmental conditions. To reduce variability, T1
plants which express MGAT1 are produced and grown under the same
conditions as control (wild-type, cultivar Oscar) plants of the
same genotype, and the oil content compared.
Expression of MGAT1 in Gossypium hirsutum Seeds
[1433] The same seed-specific chimeric gene used for the expression
of M. musculus MGAT1 in Arabidopsis thaliana seeds was used to
generate transformed Gossypium hirsutum plants. The vector
designated FP1:MGAT1 was introduced into A. tumefaciens strain AGL1
via standard electroporation procedures and cells from the
Agrobacterium culture used to introduce the chimeric DNAs into
cells of Gossypium hirsutum, variety Coker315. Cotyledons excised
from 10-day old cotton seedlings were used as explants and infected
and co-cultivated with A. tumefaciens for a period of two days.
This was followed by a six-week selection on MS medium (Murashige
and Skoog, 1962) containing 0.1 mg/L 2,4-D, 0.1 mg/L kinetin, 50
mg/L kanamycin sulphate, and 25 mg/L cefotaxime. Healthy calli
derived from the cotyledon explants were transferred to MS medium
containing 5 mg/L 6-(.gamma.,.gamma.-dimethylallylamino)-purine
(2ip), 0.1 mg/L naphthalene acetic acid (NAA), 25 mg/L kanamycin,
and 250 mg/L cefotaxime for a second period of six weeks at
28.degree. C. Somatic embryos that formed after about six to ten
weeks of incubation were germinated and maintained on the same
medium, but without added phytohormone or antibiotics. Plantlets
developed from the somatic embryos were transferred to soil and
maintained in a glasshouse once leaves and roots were developed,
with 28.degree. C./20.degree. C. (day/night) growth temperature.
Ten independent primary transgenic plants (T0) containing the
FP1-MGAT1 construct were grown in the glasshouse, flowered and
produced bolls containing seeds. The seeds were harvested on
maturity. To enhance the reliability of the oil content analysis, 5
plants were established from each of the 10 primary transgenic
plants and the mature T2 seeds are subjected to the analysis of oil
content. The seed-specific expression of MGAT1 increases oil
content and increases the percentage of polyunsaturated fatty acids
in the cotton seedoil.
Expression of a MGAT1 and MGAT2 Genes in N. benthamiana Plants
after Stable Transformation
[1434] N. benthamiana was stably transformed with the 35S:MGAT1
construct described in Example 2. 35S:MGAT1 was introduced into A.
tumefaciens strain AGL1 via standard electroporation procedure. The
transformed cells were grown on solid LB media supplemented with
kanamycin (50 mg/L) and rifampicin (25 mg/L) and incubated at
28.degree. C. for two days. A single colony was used to initiate
fresh culture. Following 48 hours vigorous culture, the cells were
collected by centrifugation at 2,000.times.g and the supernatant
was removed. The cells were resuspended in fresh solution
containing 50% LB and 50.degree. % MS medium at the density of
OD.sub.600=0.5.
[1435] Leaf samples of N. benthamiana grown in vitro were excised
and cut into square sections around 0.5-1 cm.sup.2 in size with a
sharp scalpel while immersed in the A. tumefaciens solution. The
wounded N. benthamiana leaf pieces submerged in A. tumefaciens were
allowed to stand at room temperature for 10 minutes prior to being
blotted dry on a sterile filter paper and transferred onto MS
plates without supplement. Following a co-cultivation period of two
days at 24.degree. C., the explants were washed three times with
sterile, liquid MS medium, then blotted dry with sterile filter
paper and placed on the selective MS agar supplemented with 1.0
mg/L benzylaminopurine (BAP), 0.25 mg/L indoleacetic acid (IAA), 50
mg/L kanamycin and 250 mg/L cefotaxime. The plates were incubated
at 24.degree. C. for two weeks to allow for shoot development from
the transformed N. benthamiana leaf pieces.
[1436] To establish rooted transgenic plants in vitro, healthy
green shoots were cut off and transferred into 200 mL tissue
culture pots containing MS agar medium supplemented with 25 .mu.g/L
IAA, 50 mg/L kanamycin and 250 mg/L cefotaxime. Sufficiently large
leaf discs were taken from transgenic shoots and freeze-dried for
TAG fractionation and quantification analysis as described in
Example 1 (Table 5). The best 35S:MGAT1 N. benthamiana plant had a
TAG content of 204.85 .mu.g/100 mg dry weight leaf tissue compared
with an average TAG content of 85.02 .mu.g/100 mg dry weight leaf
tissue in the control lines, representing an increase in TAG
content of 241%.
[1437] N. benthamiana was also stably transformed with the
35S:MGAT2 construct described in Example 2 and a control binary
vector pORE4 (Table 6). The best 35S:MGAT2 N. benthamiana plant had
a TAG content of 79.0 .mu.g/100 mg dry weight leaf tissue compared
with a TAG content of 9.5 .mu.g/100 mg dry weight leaf tissue in
the control line at the same developmental stage, representing an
increase in TAG content of 731%. The fatty acid profile of the TAG
fractions was also altered with significantly reduced levels of the
saturated fatty acids 16:0 and 18:0, and increased levels of the
polyunsaturated fatty acids, particularly 18:3.omega.3 (ALA) (Table
6). The fatty acid profile of the polar lipids from the same leaf
samples were not significantly affected, indicating that the
changes in the fatty acid composition of the non-polar lipids was
real. The control plants in this experiment were smaller and
different physiologically than in the previous experiment with the
35S:MGAT1 construct, and this may have explained the different oil
contents of the control plants from one experiment to the other.
Experiments to directly compare the 35S:MGAT1 and 35:MGAT2
constructs with control plants are performed using plants of the
same size and physiology.
[1438] A new set of constitutive binary expression vectors was made
using a 35S promoter with duplicated enhancer region (e35S).
35S:MGAT1#2 (pJP3346), 35S:MGAT2#2 (pJP3347) and 35S:DGAT1#2
(pJP3352) were made by first cloning the e35S promoter, contained
within a BamHI-EcoRI fragment, into pORE04 at the BamHI-EcoRI sites
to yield pJP3343. pJP3346 and pJP3347 were then produced by cloning
the MGAT1 and MGAT2 genes, respectively, into the EcoRI site of
pJP3343. pJP3352 was produced by cloning the A. thaliana DGAT1,
contained within a XhoI-AsiSI site, into the XhoI-AsiSI sites of
pJP3343.
[1439] pJP3346, pJP3347 and pJP3352 in Agrobacterium strain AGL1
were used to transform N. benthamiana as described above. Fourteen
confirmed transgenic plants were recovered for pJP3346 and 22 for
pJP3347. A number of kanamycin resistant, transformed shoots have
been generated with pJP3352. Expression analysis of the transgenes
was performed on the plants transformed with MGAT1 or MGAT2. Plants
with high levels of expression were selected. Expression analysis
on plants transformed with the A. thaliana DGAT1 is performed. The
plants grow normally and are grown to maturity. Seed is harvested
when mature. Seed from high-expressing progeny are sown directly
onto soil for lipid analysis of the T2 segregating population,
which includes both homozygous and heterozygous plants. Oil content
of leaves of plants expressing high levels of either MGAT1 or MGAT2
is significantly increased compared to plants transformed with A.
thaliana DGAT1 or control plants. MGAT2 transgenic plants showed a
significant increase in the unsaturated fatty acid 18:1 and 1%
relative increase in total fatty acid content compared to the null
events (Table 7).
[1440] pJP3346, pJP3347 and a control vector in AGL1 were also used
to transform A. thaliana as described above. Twenty-five confirmed
transgenic T2 plants comprising the T-DNA from pJP3346 and 43
transgenic plants for pJP3347 were identified. Expression analysis
was performed on the transgenic plants. Seeds from high-expressing
progeny were harvested and sown directly onto soil. Lipid analysis
including oil content of the leaves from T2 and T3 progeny was
performed, including from segregants lacking the transgenes. The
highest levels of TAG were obtained in plants that are homozygous
for the MGAT transgenes.
TABLE-US-00006 TABLE 5 Fatty acid profile and quantification of TAG
in Nicotiana benthamiana leaf tissue stably transformed with the
35S:MGAT1 construct. `M` samples are 35S:MGAT1 whilst `C` samples
are parental control plants. .mu.g/100 mg Sample C16:0 16:3w3 C18:0
C18:1 C18:1d11 C18:2 C18:3 C20:0 20:3n3 C22:0 C24:0 DW M1 38.7 0.7
5.1 8.5 0.4 7.0 34.4 1.1 0.3 0.2 0.4 204.85 M8 33.2 0.8 4.4 8.1 0.3
6.5 42.8 0.9 0.2 0.2 0.2 184.20 M3 41.1 0.6 5.3 10.4 0.4 5.5 31.8
1.0 0.4 0.2 0.2 133.62 M2 42.5 0.5 5.2 7.4 0.0 4.8 34.4 1.0 0.2 0.3
0.2 133.57 M7 35.2 0.6 4.5 8.6 0.0 4.9 41.7 1.1 0.3 0.3 0.2 128.49
M5 49.1 0.6 6.4 9.0 0.4 3.7 16.9 1.1 0.0 0.5 0.7 107.39 M4 41.9 0.4
6.0 9.6 0.0 4.2 33.0 1.1 0.2 0.4 0.2 93.71 M6 41.4 0.4 5.8 8.2 0.0
4.3 34.6 1.1 0.2 0.3 0.2 88.38 C1 40.2 0.4 6.1 8.3 0.0 7.8 31.9 1.3
0.2 0.4 0.3 81.53 C2 39.9 0.6 5.5 7.1 0.0 6.9 35.4 1.1 0.3 0.4 0.3
88.52
TABLE-US-00007 TABLE 6 Fatty acid profile and quantification of TAG
in Nicotiana benthamiana leaf tissue stably transformed with the
35S:MGAT2 construct. `M` samples are 35S:MGAT2 whilst `C` samples
are parental control plants. Two leaves from each plant were taken
and analysed separately. .mu.g/100 mg Sample C16:0 16:1d7 16:1d13t
C16:1 16:3n3 C18:0 C18:1 C18:1d11 C18:2 C18:3n C20:0 DW C, leaf 1
TAG 34.0 2.7 0.8 0.0 0.0 17.3 6.6 0.0 15.9 18.7 0.0 12.9 C, leaf 2
TAG 35.0 1.8 0.0 0.0 1.3 25.0 3.0 0.0 13.0 17.6 1.4 6.1 M, leaf 1
TAG 14.6 0.4 1.0 0.4 7.7 5.9 4.0 0.4 16.8 47.0 0.6 97.1 M, leaf 2
TAG 18.1 0.3 1.0 0.0 6.0 8.1 2.8 0.3 14.0 46.9 1.0 60.9 C, leaf 1
PL 13.4 0.0 3.0 0.2 7.4 2.0 2.5 0.4 8.4 61.4 0.3 2439.3 C, leaf 2
PL 10.3 0.0 2.4 0.2 9.7 1.4 2.0 0.3 9.5 63.3 0.0 4811.5 M, leaf 1
PL 11.6 0.0 2.4 0.2 8.7 1.9 2.4 0.3 8.7 63.0 0.0 3568.8 M, leaf 2
PL 10.7 0.0 2.4 0.2 9.5 1.6 1.9 0.3 9.2 63.3 0.0 3571.2
TABLE-US-00008 TABLE 7 Total fatty acid amount (TFA) and fatty acid
composition in Nicotiana benthamiana leaf tissues stably
transformed with the 35S:MGAT2 construct. TFA 18:1 18:1 18:3 20:1
(ug/100 ug 16:0 16:1 16:3 18:0 d9 d11 18:2 w3 20:0 20:1 iso 22:0
22:1 24:0 24:1 DW) MGAT 14.5 1.8 5.2 2.1 6.3 0.8 11.3 53.7 0.4 0.5
0.2 0.2 1.2 0.2 1.2 4.0 Nulls 15.1 2.2 6.0 2.7 3.9 0.6 9.6 56.3 0.4
0.4 0.1 0.2 0.7 0.2 1.1 3.2
[1441] Thirty plants of each transgenic line were grown in a random
arrangement in the greenhouse with parental control plants. T2
seeds were analysed for oil content and exhibited an increase of
about 2% in the oil content (total fatty acid level) compared to
the total fatty acid content of parental seeds (FIG. 8).
Expression of MGAT1 in Stably Transformed Trifolium repens
Plants
[1442] A chimeric gene encoding M. musculus MGAT1 was used to
transform Trifolium repens, another dicotyledonous plant. Vectors
containing the chimeric genes 35S:MGAT1 and 35S:DGAT1 were
introduced into A. tumefaciens via a standard electroporation
procedure. Both vectors also contain a 35S:BAR selectable marker
gene. The transformed Agrobacterium cells were grown on solid LB
media supplemented with kanamycin (50 mg/L) and rifampicin (25
mg/L) and incubated at 28.degree. C. for two days. A single colony
was used to initiate a fresh culture for each construct. Following
48 hours vigorous culture, the Agrobacterium cultures were used to
treat T. repens (cv. Haifa) cotyledons that had been dissected from
imbibed seed as described by Larkin et al. (1996). Following
co-cultivation for three days the explants were exposed to 5 mg/L
PPT to select transformed shoots and then transferred to rooting
medium to form roots, before transfer to soil. A transformed plant
containing MGAT1 was obtained. The 35S promoter is expressed
constitutively in cells of the transformed plants. The oil content
is increased in at least the vegetative tissues such as leaves.
Expression of MGAT in Stably Transformed Hordeum Vulgare
[1443] A chimeric vector including M. musculus MGAT1 was used to
produce stably transformed Hordeum vulgare, a monocotyledonous
plant. Vectors containing the chimeric genes Ubi:MGAT1 and
Ubi:DGAT1 were constructed by cloning the entire M. musculus MGAT1
and A. thaliana DGAT1 coding regions separately into pWVEC8-Ubi.
Vectors containing the chimeric genes Ubi:MGAT1 and Ubi:DGAT1 were
introduced into A. tumefaciens strain AGL1 via a standard
electroporation procedure. Transformed Agrobacterium cells were
grown on solid LB media supplemented with kanamycin (50 mg/L) and
rifampicin (25 mg/L) and the plates incubated at 28.degree. C. for
two days. A single colony of each was used to initiate fresh
cultures.
[1444] Following 48 hours vigorous culture, the Agrobacterium
cultures were used to transform cells in immature embryos of barley
(cv. Golden Promise) according to published methods (Tingay et al.,
1997; Bartlett et al., 2008) with some modifications. Briefly,
embryos between 1.5 and 2.5 mm in length were isolated from
immature caryopses and the embryonic axes removed. The resulting
explants were co-cultivated for 2-3 days with the transgenic
Agrobacterium and then cultured in the dark for 4-6 weeks on media
containing timentin and hygromycin to generate embryogenic callus
before being moved to transition media in low light conditions for
two weeks. Callus was then transferred to regeneration media to
allow for the regeneration of shoots and roots before transfer to
soil. Transformed plants were obtained and transferred to the
greenhouse. The MGAT1 coding region was expressed constitutively
under the control of the Ubi promoter in cells of the transformed
plants. Transgenic plants were generated and their tissues analysed
for oil content. Due to the low number of transgenic events
obtained in a first transformation, no statistically significant
conclusion could be drawn from the data.
[1445] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Hordeum as
described above. Vegetative tissues from the resultant transgenic
plants are increased for oil content.
Expression of MGAT in Yeast Cells
[1446] A chimeric vector including M. musculus MGAT1 was used to
transform yeast, in this example Saccharomyces cerevisiae, a fungal
microbe suitable for production of oil by fermentation. A genetic
construct Gal1:MGAT1 was made by inserting the entire coding region
of a construct designated 0954364_MGAT_pMA, contained within an
EcoRI fragment, into pYES2 at the EcoRI site, generating pJP3301.
Similarly, a genetic construct Gal1:DGAT1, used here as a
comparison and separately encoding the enzyme A. thaliana DGAT1 was
made by inserting the entire A. thaliana DGAT1 coding region into
pYES2. These chimeric vectors were introduced into S. cerevisiae
strain S288C by heat shock and transformants were selected on yeast
minimal medium (YMM) plates containing 2% raffinose as the sole
carbon source. Clonal inoculum cultures were established in liquid
YMM with 2% raffinose as the sole carbon source. Experimental
cultures were inoculated from these in YMM medium containing 1%
NP-40, to an initial OD600 of about 0.3. Cultures were grown at
28.degree. C. with shaking (about 100 rpm) until OD600 was
approximately 1.0. At this point, galactose was added to a final
concentration of 2% (w/v). Cultures were incubated at 25.degree. C.
with shaking for a further 48 hours prior to harvesting by
centrifugation. Cell pellets were washed with water before being
freeze-dried for lipid class fractionation and quantification
analysis as described in Example 1. The Gal promoter is expressed
inducibly in the transformed yeast cells, increasing the oil
content in the cells.
[1447] The coding region of the mouse MGAT2 gene, codon optimised
for expression in yeast cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into yeast. The
resultant transgenic cells are increased for oil content. The genes
are also introduced into the oleaginous yeast, Yarrowia lipolytica,
to increase oil content.
Expression of MGAT in Algal Cells Chlamydomonas Reinhardtii
[1448] A chimeric vector including M. musculus MGAT1 is used to
stably transform algal cells. The genetic constructs designated
35S:MGAT1 is made by cloning the MGAT1 coding region into a cloning
vector containing a Cauliflower mosaic virus 35S promoter cassette
and a paramomycin-resistance gene
(aminoglycoside-O-phosphotransferase VIII) expressed by a C.
reinhardtii RBCS2 promoter. 35S:MGAT1 is introduced separately into
a logarithmic culture of 5.times.10.sup.7 cc503, a
cell-wall-deficient strain of Chlamydomonas reinhardtii by a
modified glass bead method (Kindle, 1990). Both vectors also
contain the BLE resistance gene as a selectable marker gene.
Briefly, a colony of non-transformed cells on a TAP agar plate kept
at about 24.degree. C. is grown to about 5.times.10.sup.6 cells/mL
over four days, the resultant cells are pelleted at 3000 g for 3
minutes at room temperature and resuspended to produce
5.times.10.sup.7 cells in 300 uL of TAP media. 300 uL of 0.6 mm
diameter glass beads, 0.6 .mu.g plasmid in 5 .mu.L and 100 .mu.L of
20% PEG MW8000 are added and the mix is vortexed at maximum speed
for 30 seconds, then transferred to 10 mL of TAP and incubated for
16 hours with shaking in the dark. The cells are pelleted,
resuspended in 200 .mu.L of TAP then plated on TAP plates
containing 5 mg/L zeocin and incubated in the dark for 3 weeks.
Transformed colonies are subcultured to a fresh TAP+zeocin 5 mg/L
plate after which they are grown up under standard media conditions
with zeocin selection. After harvesting by centrifugation, the cell
pellets are washed with water before being freeze-dried for lipid
class fractionation and quantification analysis as described in
Example 1. The 35S:MGAT1 promoter is expressed constitutively in
the transformed algal cells. The oil content of the cells is
significantly increased.
[1449] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
construct mentioned above, and introduced into Chlamydomonas. Oil
content in the resultant transgenic cells is significantly
increased.
Expression of MGAT in Stably Transformed Lupinus Angustifolius
[1450] A chimeric vector including M. musculus MGAT1 is used to
transform Lupinus angustifolius, a leguminous plant Chimeric
vectors 35S:MGAT1 and 35S: DGAT1 in Agrobacterium are used to
transform L. angustifolius as described by Pigeaire et al. (1997).
Briefly, shoot apex explants are co-cultivated with transgenic
Agrobacterium before being thoroughly wetted with PPT solution (2
mg/ml) and transferred onto a PPT-free regeneration medium. The
multiple axillary shoots developing from the shoot apices are
excised onto a medium containing 20 mg/L PPT and the surviving
shoots transferred onto fresh medium containing 20 mg/L PPT.
Healthy shoots are then transferred to soil. The 35S promoter is
expressed constitutively in cells of the transformed plants,
increasing the oil content in the vegetative tissues and the seeds.
A seed specific promoter is used to further increase the oil
content in transgenic Lupinus seeds.
[1451] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Lupinus. Seeds and
vegetative tissues from the resultant transgenic plants are
increased for oil content.
Expression of MGAT in Stably Transformed Cells of Sorghum
Bicolor
[1452] A chimeric vector including M. musculus MGAT1 is used to
stably transform Sorghum bicolor. Ubi:MGAT1 and Ubi:DGAT1 in A.
tumefaciens strain AGL1 are used to transform Sorghum bicolor as
described by Gurel et al. (2009). The Agrobacterium is first
centrifuged at 5,000 rpm at 4.degree. C. for 5 minutes and diluted
to OD550=0.4 with liquid co-culture medium. Previously isolated
immature embryos are then covered completely with the Agrobacterium
suspension for 15 minutes and then cultured, scutellum side up, on
co-cultivation medium in the dark for 2 days at 24.degree. C. The
immature embryos are then transferred to callus-induction medium
(CIM) with 100 mg/L carbenicillin to inhibit the growth of the
Agrobacterium and left for 4 weeks. Tissues are then transferred to
regeneration medium to shoot and root. The Ubi promoter is
expressed constitutively in cells of the transformed plants,
increasing the oil content in at least the vegetative tissues.
[1453] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Sorghum. Vegetative
tissues from the resultant transgenic plants are increased for oil
content.
Expression of MGAT in Stably Transformed Plants of Glycine Max
[1454] A chimeric gene encoding M. musculus MGAT1 is used to stably
transform Glycine max, another legume which may be used for oil
production. 35S:MGAT1 in Agrobacterium is used to transform G. max
as described by Zhang et al. (1999). The Agrobacterium is
co-cultivated for three days with cotyledonary explants derived
from five day old seedlings. Explants are then cultured on
Gamborg's B5 medium supplemented with 1.67 mg/L BAP and 5.0 mg/L
glufosinate for four weeks after which explants are subcultured to
medium containing MS major and minor salts and B5 vitamins (MS/BS5)
supplemented with 1.0 mg/L zeatin-riboside, 0.5 mg/L GA3 and 0.1
mg/L IAA amended with 1.7 mg/L or 2.0 mg/L glufosinate. Elongated
shoots are rooted on a MS/B5 rooting medium supplemented with 0.5
mg/L NAA without further glufosinate selection. The 35S promoter is
expressed constitutively in cells of the transformed plants,
increasing the oil content in the vegetative tissues and the
seeds.
[1455] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Glycine. Vegetative
tissues and seeds from the resultant transgenic plants are
increased for oil content.
Expression of MGAT in Stably Transformed Zea mays
[1456] A chimeric gene encoding M. musculus MGAT1 is used to stably
transform Zea mays. The vectors comprising 35S:MGAT1 and 35S:DGAT1
are used to transform Zea mays as described by Gould et al. (1991).
Briefly, shoot apex explants are co-cultivated with transgenic
Agrobacterium for two days before being transferred onto a MS salt
media containing kanamycin and carbenicillin. After several rounds
of sub-culture, transformed shoots and roots spontaneously form and
are transplanted to soil. The 35S promoter is expressed in cells of
the transformed plants, increasing the oil content in the
vegetative tissues and the seeds.
[1457] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Zea mays.
Vegetative tissues and seeds from the resultant transgenic plants
are increased for oil content. Alternatively, the MGAT coding
regions are expressed under the control of an endosperm specific
promoter such as the zein promoter, or an embryo specific promoter
obtained from a monocotyledonous plant, for increased expression
and increased oil content in the seeds. A further chimeric gene
encoding a GPAT with phosphatase activity, such as A. thaliana
GPAT4 or GPAT6 is introduced into Zea mays in combination with the
MGAT, further increasing the oil content in corn seeds.
Expression of MGAT in Stably Transformed Elaeis guineensis (Palm
Oil)
[1458] A chimeric gene encoding M. musculus MGAT1 is used to stably
transform Elaeis guineensis. Chimeric vectors designated Ubi:MGAT1
and Ubi:DGAT1 in Agrobacterium are used. Following 48 hours
vigorous culture, the cells are used to transform Elaeis guineensis
as described by Izawati et al. (2009). The Ubi promoter is
expressed constitutively in cells of the transformed plants,
increasing the oil content in at least the fruits and seeds, and
may be used to obtain oil.
[1459] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Elaeis. Seeds from
the resultant transgenic plants are increased for oil content.
Expression of MGAT in Stably Transformed Avena saliva (Oats)
[1460] A chimeric gene encoding M. musculus MGAT1 is used to stably
transform Avena saliva, another monocotyledonous plant. Chimeric
vectors designated Ubi: MGAT1 and Ubi: DGAT1, as described above
and both containing a Ubi:BAR selectable marker, are used to
transform Avena sativa as described by Zhang et al. (1999).
[1461] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, is substituted for the MGAT1 in the
constructs mentioned above, and introduced into Avena. Seeds from
the resultant transgenic plants are increased for oil content.
Example 7. Engineering a MGAT with DGAT Activity
[1462] An MGAT with altered DGAT activity, especially increased
DGAT activity and potentially increased MGAT activity may be
engineered by performing random mutagenesis, targeted mutagenesis,
or saturation mutagenesis on MGAT gene(s) of interest or by
subjecting different MGAT and/or DGAT genes to DNA shuffling. DGAT
function can be positively screened for by using, for example, a
yeast strain that has an absolute requirement for TAG-synthesis
complementation when fed free fatty acids, such as strain H1246
which contains mutations in four genes (DGA1, LRO1, ARE1, ARE2).
Transforming the MGAT variants in such a strain and then supplying
the transformed yeast with a concentration of free fatty acids that
prevents complementation by the wildtype MGAT gene will only allow
the growth of variants with increased TAG-synthesis capability due
to improved DGAT activity. The MGAT activity of these mutated genes
can be determined by feeding labelled sn-1 or sn-2 MAG and
quantifying the production of labelled DAG. Several rounds of
directed evolution in combination with rational protein design
would result in the production of a novel MGAT gene with similar
MGAT and DGAT activities.
[1463] The gene coding for the M. musculus MGAT1 acyltransferase
was subjected to error prone PCR using Taq DNA polymerase in the
presence of 0.15 mM MnCl.sub.2 to introduce random mutations. The
randomized coding regions were then used as megaprimers to amplify
the entire yeast expression vector using high fidelity PCR reaction
conditions. Sequencing of 9099 bp of recovered, mutagenised DNA
revealed a mutational frequency of about 0.8%, corresponding to 8
mutations per gene or, on average, 5.3 amino acid substitutions per
polypeptide. The entire mutagenised library was transformed into E.
coli DH5a for storage at -80.degree. C. and plasmid preparation.
The size of the MGAT1 library was estimated at 3.8356E6 clones. A
copy of the MGAT1 library was transformed into the yeast strain
H1246, resulting in a library size of 3E6 clones. The MGAT1 library
as well as a pYES2 negative control, transformed into S. cerevisiae
H1246, were subjected to 8 selection rounds, each consisting of
(re)diluting cultures in minimal induction medium (1% rafinose+2%
galactose; diluted to OD.sub.600=0.35-0.7) in the presence of C18:1
free fatty acid at a 1 mM final concentration. Negative controls
consisted of identical cultures grown simultaneously in minimal
medium containing glucose (2%) and in the absence of C18:1 free
fatty acid. After 8 selection rounds, an aliquot of the selected
MGAT1 library was plated on minimal medium containing glucose (2%).
A total of 120 colonies were grown in 240 .mu.l minimal induction
medium in 96 microtiter plates and assayed for neutral lipid yield
using a Nile Red fluorescence assay as described by Siloto et al.
(2009). Plasmid minipreps were prepared from 113 clones (=top 6%)
that displayed the highest TAG levels.
[1464] The entire MGAT1 coding region of the selected clones is
sequenced to identify the number of unique mutants and to identify
the nature of the selected mutations. Unique MGAT1 mutants are
retransformed into S. cerevisiae H1246 for in vitro MGAT and DGAT
assays using labelled MAG and C18:1 substrates respectively (see
Example 5). Selected MGAT1 variants are found to exhibit increased
DGAT activity compared to the wild type acyltransferase, whilst
MGAT activity is possibly increased as well.
[1465] MGAT1 variants displaying increased MGAT and/or DGAT
activities are used as parents in a DNA shuffling reaction. The
resulting library is subjected to a similar selection system as
described above resulting in further improvement of general
acyltransferase activity. In addition, free fatty acids other than
C18:1 are added to the growth medium to select for MGAT1 variants
displaying altered acyl-donor specificities.
Example 8. Constitutive Expression of the A. thaliana
Diacylglycerol Acyltransferase 2 in Plants
[1466] Expression of the A. thaliana DGAT2 in yeast (Weselake et
al., 2009) and insect cells (Lardizabal et al., 2001) did not
demonstrate DGAT activity. Similarly, the DGAT2 was not able to
complement an A. thaliana DGAT1 knockout (Weselake et al., 2009).
The enzyme activity of the A. thaliana DGAT2 in leaf tissue was
determined using a N. benthamiana transient expression system as
described in Example 1. The A. thaliana DGAT2 (accession Q9ASU1)
was obtained by genomic PCR and cloned into a binary expression
vector under the control of the 35S promoter to generate 35S:DGAT2.
This chimeric vector was introduced into A. tumefaciens strain AGL1
and cells from cultures of these infiltrated into leaf tissue of N.
benthamiana plants in a 24.degree. C. growth room using 35S:DGAT1
as a control. Several direct comparisons were infiltrated with the
samples being compared located on either side of the same leaf.
Experiments were performed in triplicate. Following infiltration
the plants were grown for a further five days before leaf discs
were taken and freeze-dried for lipid class fractionation and
quantification analysis as described in Example 1. This analysis
revealed that both DGAT1 and DGAT2 were functioning to increase
leaf oil levels in Nicotiana benthamiana (Table 8).
[1467] Leaf tissue transformed with the 35S:p19 construct (negative
control) contained an average of 25 .mu.g TAG/100 mg dry leaf
weight. Leaf tissue transformed with the 35S:p19 and 35S:DGAT1
constructs (positive control) contained an average of 241 .mu.g
TAG/100 mg dry leaf weight. Leaf tissue transformed with the
35S:p19 and 35S:DGAT2 constructs contained an average of 551 .mu.g
TAG/100 mg dry leaf weight.
[1468] The data described above demonstrates that the A. thaliana
DGAT2 enzyme is more active than the A. thaliana DGAT1 enzyme in
promoting TAG accumulation in leaf tissue. Expression of the DGAT2
gene resulted in 229% as much TAG accumulation in leaf tissue
compared to when the TAG amount from DGAT1 over-expressed was set
as relative 100% (FIG. 9).
[1469] Transiently-transformed N. benthamiana leaf tissues
expressing P19 alone (control), or P19 with either AtDGAT1 or
AtDGAT2 were also used to prepare microsomes for in vitro assays of
enzyme activity. A DGAT biochemical assay was performed using
microsomes corresponding to 50 .mu.g protein and adding 10 nmole
[14]C6:0-DAG and 5 nmole acyl-CoA, in 50 mM Hepes buffer, pH 7.2,
containing 5 mM MgCl.sub.2, and 1% BSA in a final volume of 100
.mu.L for each assay. The assays were conducted at 30.degree. C.
for 30 minutes. Total lipid from each assay was extracted and
samples loaded on TLC plates, which were developed using a
hexane:DEE:Hac solvent (70:30:1 vol:vol:vol). The amount of
radioactivity in DAG and TAG spots was quantified by PhosphorImage
measurement. The percentage of DAG converted to TAG was calculated
for each of the microsome preparations.
[1470] Some endogenous DGAT activity was detected in the N.
benthamiana leaves, as the P19 control assay showed low levels of
TAG production. The expression of AtDGAT1 yielded increased DGAT
activity relative to the P19 control when the assays were
supplemented with either C18:1-CoA or C18:2-CoA, but not when
supplemented with C18:3-CoA, where the levels of TAG for the P19
control and the AtDGAT1 were similar. However, in all of the
microsomal assays when AtDGAT2 was expressed in the leaf tissues,
greater levels of DGAT activity (TAG production) were observed
compared to the AtDGAT1 microsomes. Greater levels of TAG
production were observed when the microsomes were supplemented with
either C18:2-CoA or C18:3-CoA relative to C18:1-CoA (FIG. 10). This
indicated that DGAT2 had a different substrate preference, in
particular for C18:3-CoA (ALA), than DGAT1.
Example 9. Co-Expression of MGAT and GPAT in Transgenic Seed
[1471] Yang et al. (2010) described two glycerol-3-phosphate
acyltransferases (GPAT4 and GPAT6) from A. thaliana both having a
sn-2 preference (i.e. preferentially forming sn-2 MAG rather than
sn-1/3 MAG) and phosphatase activity, which were able to produce
sn-2 MAG from G-3-P (FIG. 1). These enzymes were proposed to be
part of the cutin synthesis pathway. GPAT4 and GPAT6 were not
expressed highly in seed tissue. Combining such a bifunctional
GPAT/phosphatase with a MGAT yields a novel DAG synthesis pathway
using G-3-P as a substrate that can replace or supplement the
typical Kennedy Pathway for DAG synthesis in plants, particularly
in oilseeds, or other cells, which results in increased oil
content, in particular TAG levels.
[1472] Chimeric DNAs designated pJP3382 and pJP3383, encoding the
A. thaliana GPAT4 and GPAT6, respectively, together with the M.
musculus MGAT2 for expression in plant seeds were made by first
inserting the entire MGAT2 coding region, contained within a SwaI
fragment, into pJP3362 at the SmaI site to yield pJP3378. pJP3362
was a binary expression vector containing empty FAE1 and FP1
expression cassettes and a kanamycin resistance gene as a
selectable marker. The A. thaliana GPAT4 was amplified from cDNA
and cloned into pJP3378 at the NotI site to yield pJP3382 in which
the GPAT4 was expressed by the truncated napin promoter, FP1, and
the MGAT2 was expressed by the A. thaliana FAE1 promoter.
Similarly, the A. thaliana GPAT6 was amplified from cDNA and cloned
into pJP3378 at the NotI site to yield pJP3384 in which the GPAT6
was operably linked to the truncated napin promoter, FP1, and the
MGAT2 was expressed by the A. thaliana FAE1 promoter. pJP3382 and
pJP3383 were transformed into A. thaliana (ecotype Columbia) by the
floral dip method. Seeds from the treated plants were plated onto
media containing the antibiotic, kanamycin, to select for progeny
plants (T1 plants) which were transformed. Transgenic seedlings
were transferred to soil and grown in the greenhouse. Expression of
the transgenes in the developing embryos was determined. Transgenic
plants with the highest level of expression and which show a 3:1
ratio for transgenic:non-transgenic plants per line, indicative of
a single locus of insertion of the transgenes, are selected and
grown to maturity. Seeds were obtained from these plants (T2) which
included some which were homozygous for the transgenes. 30 to 32
(12 plants) from each line were grown in pots of soil in a random
arrangement in the greenhouse with control plants, and the lipid
content, TAG content and fatty acid compositions of the resultant
seed was determined. The total fatty acid content (as determined
from the total FAME), in particular the TAG content of the seeds
comprising both a MGAT and a GPAT4 or GPAT6 was substantially and
significantly increased by nearly 3% (absolute level) or by about
9% (relative increase) over the controls, and increased relative to
seeds comprising the MGAT alone or the A. thaliana DGAT1 alone
(FIG. 11).
[1473] The coding region of the mouse MGAT2 gene, codon optimised
for expression in plant cells, was introduced into Brassica napus
together with a chimeric gene encoding Arabidopsis GPAT4. Seeds
from the resultant transgenic plants were harvested and some were
analysed. Data from these preliminary analyses showed variability
in the oil content and fatty acid composition, probably due to the
plants being grown at different times and under different
environmental conditions. Seeds are planted to produce progeny
plants, and progeny seeds are harvested.
Example 10. Testing the Effect of GPAT4 and GPAT6 on MGAT-Mediated
TAG Increase by GPAT Silencing and Mutation
[1474] The GPAT family is large and all known members contain two
conserved domains, a plsC acyltransferase domain and a HAD-like
hydrolase superfamily domain. In addition to this, A. thaliana
GPAT4-8 all contain an N-terminal region homologous to a
phosphoserine phosphatase domain. A. thaliana GPAT4 and GPAT6 both
contain conserved residues that are known to be critical to
phosphatase activity (Yang et al., 2010).
[1475] Degenerate primers based on the conserved amino acid
sequence GDLVICPEGTICREP (SEQ ID NO:228) were designed to amplify
fragments on N. benthamiana GPATs expressed in leaf tissue. 3' RACE
will be performed using these primers and oligo-dT reverse primers
on RNA isolated from N. benthamiana leaf tissue. GPATs with
phosphatase activity (i.e. GPAT4/6-like) will be identified by
their homology with the N-terminal phosphoserine phosphatase domain
region described above. 35S-driven RNAi constructs targeting these
genes will be generated and transformed in A. tumefaciens strain
AGL1. Similarly, a 35S:V2 construct containing the V2 viral
silencing-suppressor protein will be transformed in A. tumefaciens
strain AGL1. V2 is known to suppress the native plant silencing
mechanism to allow effective transient expression but also allow
RNAi-based gene silencing to function.
[1476] TAG accumulation will then be compared between
transiently-transformed leaf samples infiltrated with the following
strain mixtures: 1) 35S:V2 (negative control); 2) 35S:V2+35S:MGAT2
(positive control); 3) 35S:V2+GPAT-RNAi; 4)
35S:V2+GPAT-RNAi+35S:MGAT2. It is expected that the
35S:V2+GPAT-RNAi+35S:MGAT2 mixture will result in less TAG
accumulation than the 35S:V2+35S:MGAT2 sample due to interrupted
sn-2 MAG synthesis resulting from the GPAT silencing.
[1477] A similar experiment will be performed using A. thaliana and
N. benthamiana GPAT4/6-like sequences which are mutated to remove
the conserved residues that are known to be critical to phosphatase
activity (Yang et al., 2010). These mutated genes (known
collectively as GPAT4/6-delta) will then be cloned into 35S-driven
expression binary vectors and transformed in A. tumefaciens. TAG
accumulation will then be compared between transiently-transformed
leaf samples infiltrated with the following strain mixtures: 1)
35S:p19 (negative control); 2) 35S:p19+35S:MGAT2 (positive
control); 3) 35S:p19+GPAT4/6-delta; 4)
35S:p19+GPAT4/6-delta+35S:MGAT2. It is expected that the
35S:p19+GPAT4/6-delta+35S:MGAT2 mixture will result in less TAG
accumulation than the 35S:p19+35S:MGAT2 sample due to interrupted
sn-2 MAG synthesis resulting from the GPAT mutation. Whilst the
native N. benthamiana GPAT4/6-like genes will be present in this
experiment it is expected that high-level expression of the
GPAT4/6-delta constructs will outcompete the endogenous genes for
access to the G-3-P substrate.
Example 11. Constitutive Expression of a Diacylglycerol
Acyltransferase and WRI1 Transcription Factor in Plant Cells
[1478] A vector designated 35S-pORE04 was made by inserting a PstI
fragment containing a 35S promoter into the SfoI site of vector
pORE04 after T4 DNA polymerase treatment to blunt the ends (Coutu
et al., 2007). A genetic construct 35S:Arath-DGAT1 encoding the A.
thaliana diacylglycerol acyltransferase DGAT1 (Bouvier-Nave et al.,
2000) was made. Example 3 of WO 2009/129582 describes the
construction of AtDGAT1 in pXZP163. A PCR amplified fragment with
KpnI and EcoRV ends was made from pXZP163 and inserted into pENTR11
to generate pXZP513E. The entire AtDGAT1 coding region of pXZP513E
contained within a BamHI-EcoRV fragment was inserted into
35S-pORE04 at the BamHI-EcoRV site, generating pJP2078. A synthetic
fragment, Arath-WRI1, coding for the A. thaliana WRI1 transcription
factor (Cernac and Benning, 2004), flanked by EcoRI restriction
sites and codon optimized for B. napus, was synthesized. A genetic
construct designated 35S:Arath-WRI1 was made by cloning the entire
coding region of Arath-WRI1, flanked by EcoRI sites into 35S-pORE04
at the EcoRI site generating pJP3414. Expression of the genes in N.
benthamiana leaf tissue was performed according to the transient
expression system as described in Example 1.
[1479] Quantification of TAG levels of infiltrated N. benthamiana
leaves by Iatroscan revealed that the combined expression of the A.
thaliana DGAT1 and WRI1 genes resulted in 4.5-fold and 14.3-fold
increased TAG content compared to expression of WRI1 and the V2
negative control respectively (Table 9). This corresponded to an
average and maximum observed TAG yield per leaf dry weight of 5.7%
and 6.51% respectively (Table 9 and FIG. 12). The increase in leaf
oil was not solely due to the activity of the overexpressed DGAT1
acyltransferase as was apparent in the reduced TAG levels when WRI1
was left out of the combination. Furthermore, a synergistic effect
was observed accounting for 48% of the total TAG increase.
[1480] Both DGAT1 and WRI1 constructs also led to increased oleic
acid levels at the expense of linoleic acid in TAG fractions of
infiltrated N. benthamiana leaves (Table 10). These results confirm
recent findings by Andrianov et al. (2010) who reported similar
shifts in the TAG, phospholipid and TFA lipid fractions of
transgenic tobacco plants transformed with the A. thaliana DGAT1
acyltransferase. However, when DGAT1 and WRI1 genes were
co-expressed, a synergistic effect was observed on the accumulation
of oleic acid in the N. benthamiana leaves--this synergism
accounted for an estimated at 52% of the total oleic acid content
when both genes were expressed. The unexpected synergistic effects
on both TAG accumulation and oleic acid levels in transgenic N.
benthamiana leaves demonstrated the potential of simultaneously
up-regulating fatty acid biosynthesis and acyl uptake into
non-polar lipid such as TAG in vegetative tissues, two metabolic
processes that are highly active in developing oilseeds.
[1481] The transient expression experiment was repeated except that
the P19 viral silencing suppressor as substituted for the V2
suppressor, and with careful comparison of samples on the same leaf
to avoid any leaf-to-leaf variation. For this, a chimeric 35S:P19
construct for expression of the tomato bushy stunt virus P19 viral
silencing suppressor protein (Wood et al., 2009) was separately
introduced into A. tumefaciens GV3101 for co-infiltration.
[1482] Quantification of TAG levels of infiltrated N. benthamiana
leaves by Iatroscan in this experiment revealed that the combined
transient expression of the A. thaliana DGAT1 and WRI1 genes
resulted in 141-fold increased TAG content compared to P19 negative
control (FIG. 13). When compared to the expression of the DGAT1 and
WRI1 genes separately on the same leaf, the combined infiltration
increased TAG levels by 17- and 5-fold respectively. Once again,
the co-expression of both genes had a synergistic (larger than
additive) effect on leaf oil accumulation with the synergistic
component accounting for 73% of the total TAG increase. The greater
extent of the increased TAG content in this experiment (141-fold)
compared to the previous experiment (14.3-fold) may have been due
to use of the P19 silencing suppressor rather than V2 and therefore
increased gene expression from the transgenes.
[1483] Table 11 shows the fatty acid composition of the TAG. When
DGAT1 and WRI1 genes were co-expressed in N. benthamiana, a
synergistic effect was once again observed on the level of oleic
acid accumulation in the leaf TAG fraction. This increase was
largely at the expense of the medium chain unsaturated fatty acids
palmitic acid and stearic acid (Table 11). Linoleic acid was also
increased which can be explained by the higher oleic acid substrate
levels available to the endogenous FAD2 .DELTA.12-desaturase.
Individual expression of the DGAT1 and WRI1 genes in N. benthamiana
led to intermediate changes in the TAG profile without as great an
increase in oleic acid. In addition, but in contrast to the first
experiment, higher levels of .alpha.-linolenic acid (ALA) were
detected while this was observed to a lesser extent upon the DGAT1
and WRI1 coexpression in leaf tissue.
[1484] The observed synergistic effect of DGAT1 and WRI1 expression
on TAG biosynthesis was confirmed in more detail by comparing the
effect of introduction into N. benthamiana of both genes
individually or in combination, compared to introduction of a P19
gene alone as a control, within the same leaf. This was beneficial
in reducing leaf to leaf variation. In addition, the number of
replicates was increased to 5 and samples were pooled across
different leaves from the same plant to improve the quality of the
data. Results are presented in Table 12.
TABLE-US-00009 TABLE 8 Fatty acid profile and quantification of TAG
in triplicate Nicotiana benthamiana leaf tissue transiently
transformed with the 35S:p19, 35S:DGAT1 and 35S:DGAT2 constructs.
.mu.g/100 mg Sample C16:0 16:1w13t C16:1d7 16:3w3 C18:0 C18:1
C18:1d11 C18:2 C18:3 C20:0 20:1d11 20:2 20:3n3 C22:0 C24:0 DW P19
44.7 0.1 0.0 0.0 33.9 1.2 0.0 6.5 12.7 0.9 0.0 0.0 0.0 0.0 0.0
43.29 44.1 1.7 0.0 0.0 15.3 2.0 0.0 15.2 19.5 2.2 0.0 0.0 0.0 0.0
0.0 23.12 43.3 1.5 0.0 0.0 10.5 1.5 0.0 17.2 23.9 2.2 0.0 0.0 0.0
0.0 0.0 38.35 P19 + 36.3 0.5 0.1 0.4 11.6 2.3 0.3 17.8 24.5 3.6 0.0
0.0 0.2 1.5 0.2 144.77 AtDGAT1 33.6 0.5 0.1 0.4 11.2 2.9 0.3 23.1
21.5 3.8 0.0 0.0 0.2 1.5 0.9 145.34 36.8 0.5 0.0 0.0 12.4 2.9 0.4
21.3 19.3 3.9 0.0 0.0 0.0 1.5 1.0 90.04 P19 + 18.6 0.3 0.1 0.5 9.3
7.7 0.4 28.0 33.1 1.1 0.2 0.1 0.1 0.2 0.3 439.25 AtDGAT2 17.5 0.3
0.1 0.3 10.2 9.9 0.5 32.7 26.5 1.2 0.1 0.0 0.1 0.2 0.4 282.50 18.4
0.3 0.1 0.3 9.8 7.5 0.5 32.3 29.1 1.2 0.0 0.0 0.0 0.3 0.2
208.40
TABLE-US-00010 TABLE 9 TAG levels in triplicate Nicotiana
benthatmiana leaf tissue transiently transformed with 35S:V2,
35S:DGAT1 and 35S:WRI1. TAG (% TAG (% Control dry dry combination
weight) .sup.1 Genes expressed weight) .sup.1 Ratio .sup.2 V2 0.41
.+-. 0.10 V2, WRI1, DGAT1 5.71 .+-. 0.63 14.28 .+-. 1.89 V2, WRI1
1.16 .+-. 0.60 V2, WRI1, DGAT1 4.25 .+-. 0.64 4.45 .+-. 2.24 V2,
DGAT1 1.52 .+-. 0.34 V2, WRI1, DGAT1 4.76 .+-. 0.50 3.22 .+-. 0.75
.sup.1 Average of three different infiltrated leaves as quantified
by Iatroscan .sup.2 Average ratio based on side-by-side comparisons
on the same leaves
TABLE-US-00011 TABLE 10 Fatty acid composition of TAG produced in
Nicotiana benthamiana leaf tissue transiently transformed with
35S:V2, 35S:DGAT1 and 35S:WRI1 (data from triplicate
infiltrations). V2, WRI1, V2, WRI1, V2, WRI1, Fatty acid V2 DGAT1
V2, WRI1 DGAT1 V2, DGAT1 DGAT1 C14:0 0 0 0 0 0 0 C14:1.sup..DELTA.9
1.26 .+-. 2.18 0.05 .+-. 0.10 0 0.04 .+-. 0.08 0 0.04 .+-. 0.07
C16:0 46.12 .+-. 0.97 30.60 .+-. 0.41 50.09 .+-. 6.27 31.32 .+-.
3.31 35.44 .+-. 0.80 26.61 .+-. 1.41 C16:1.sup..DELTA.9 0 0.13 .+-.
0.11 0 0.07 .+-. 0.11 0 0.13 .+-. 0.12 C18:0 13.44 .+-. 1.65 9.93
.+-. 1.19 9.28 .+-. 0.81 9.93 .+-. 0.53 12.20 .+-. 1.03 8.76 .+-.
0.91 C18:1.sup..DELTA.9 5.09 .+-. 5.32 36.78 .+-. 2.23 9.72 .+-.
5.08 27.97 .+-. 4.19 8.77 .+-. 1.97 32.41 .+-. 1.39
C18:1.sup..DELTA.11 0 0.56 .+-. 0.04 0 0.51 .+-. 0.04 0 0.55 .+-.
0.04 C18:2.sup..DELTA.9, 12 14.12 .+-. 0.75 11.83 .+-. 0.75 13.26
.+-. 1.95 16.45 .+-. 3.88 18.93 .+-. 0.77 17.03 .+-. 1.36
C18:3.sup..DELTA.9, 12, 15 19.98 .+-. 6.33 4.77 .+-. 1.17 17.10
.+-. 4.31 8.75 .+-. 2.13 16.12 .+-. 3.36 9.57 .+-. 0.61 C20:0 0
2.63 .+-. 0.27 0.54 .+-. 0.93 2.53 .+-. 0.16 4.25 .+-. 0.33 2.43
.+-. 0.26 C22:0 0 1.56 .+-. 0.1 0 1.38 .+-. 0.03 2.37 .+-. 0.11
1.40 .+-. 0.13 C24:0 0 1.17 .+-. 0.15 0 1.05 .+-. 0.07 1.92 .+-.
0.16 1.07 .+-. 0.16
TABLE-US-00012 TABLE 11 Fatty acid composition of TAG produced in
N. benthamiana leaf tissues transiently transformed with 35S:P19
(control), 35S:WRI1 and/or 35S:DGAT1 constructs. P19 + P19 + WRI1 +
Fatty acid P19 P19 + WRI1 DGAT1 DGAT1 C14:0 3.0 .+-. 2.2 0.6 .+-.
0.1 0.2 .+-. 0.1 0.1 .+-. 0.0 C16:0 46.5 .+-. 4.1 48.7 .+-. 11.5
28.4 .+-. 0.3 28.1 .+-. 1.0 C16:1.sup..DELTA.3t 1.3 .+-. 2.2 0.3
.+-. 0.3 0.5 .+-. 0.0 0.3 .+-. 0.0 C16:1.sup..DELTA.9 0.0 0.9 .+-.
0.2 0.2 .+-. 0.0 0.4 .+-. 0.1 C16:3.sup..DELTA.7,12,15 0.0 0.2 .+-.
0.2 0.5 .+-. 0.1 0.3 .+-. 0.0 C18:0 18.7 .+-. 4.7 7.9 .+-. 2.6 11.5
.+-. 0.6 7.2 .+-. 0.4 C18:1.sup..DELTA.9 5.5 .+-. 1.3 3.9 .+-. 0.3
6.3 .+-. 0.2 19.4 .+-. 2.7 C18:1.sup..DELTA.11 0.0 0.6 .+-. 0.1 0.2
.+-. 0.0 0.6 .+-. 0.1 C18:2.sup..DELTA.9,12 11.3 .+-. 4.2 12.7 .+-.
3.6 25.2 .+-. 0.5 26.3 .+-. 1.0 C18:3.sup..DELTA.9,12,15 9.3 .+-.
3.6 21.6 .+-. 10.3 18.1 .+-. 0.6 11.2 .+-. 0.7 C20:0 2.7 .+-. 0.2
1.4 .+-. 0.5 4.4 .+-. 0.1 2.7 .+-. 0.1 C20:1.sup..DELTA.11 0.0 0.0
0.3 .+-. 0.0 0.3 .+-. 0.0 C20:2.sup..DELTA.11,14 0.0 0.0 0.1 .+-.
0.1 0.2 .+-. 0.0 C20:3.sup..DELTA.11,14,17 0.0 0.0 0.1 .+-. 0.0 0.1
.+-. 0.0 C22:0 1.5 .+-. 0.1 0.7 .+-. 0.1 2.3 .+-. 0.0 1.8 .+-. 0.1
C24:0 0.4 .+-. 0.6 0.5 .+-. 0.2 1.6 .+-. 0.1 1.0 .+-. 0.1
TABLE-US-00013 TABLE 12 Comparison of WRI1 + DGAT1 together with
the single genes TAG Gene combination level (% dry weight) Ratio
(compared to P19) P19 (control) 0.01 .+-. 0.00 1 P19 + WRI1 0.08
.+-. 0.04 8 P19 + DGAT1 0.27 .+-. 0.03 27 P19 + WRI1 + DGAT1 1.29
.+-. 0.26 129
[1485] Based on the individual effects of both DGAT1 and WRI1 genes
upon expression in N. benthamiana, in the presence of merely an
additive effect but the absence of any synergistic effect, the
present inventors expected a TAG level of about 0.35 or a 35-fold
increase compared to the P19 negative control. However, the
introduction of both genes resulted in TAG levels that were
129-fold higher than the P19 control. Based on these results, the
present inventors estimated the additive effect and the synergistic
effect on TAG accumulation as 26.9% and 73.1%, respectively. In
addition, when the fatty acid composition of the total lipid in the
leaf samples was analysed by GC, a synergistic effect was observed
on C18:1.sup..DELTA.9 levels in the TAG fraction of N. benthamiana
leaves infiltrated with WRI1 and DGAT1 (3 repeats each). The data
is shown in Table 11.
[1486] For seed-specific expression of the WRI1+DGAT1 combination,
Arabidopsis thaliana was transformed with a binary vector construct
including a chimeric DNA having both pFAE1::WRI1 and pCIn2::DGAT1
genes, or, for comparison, the single genes pFAE1::WRI1 or
pCln2::DGAT1. T1 seeds were harvested from the plants. The oil
content of the seeds is determined. The seeds have an increased oil
content.
Example 12. Constitutive Expression of a Monoacylglycerol
Acyltransferase and WRI1 Transcription Factor in Plant Cells
[1487] A chimeric DNA encoding the Mus musculus MGAT2 (Cao et al.,
2003; Yen and Farese, 2003) and codon-optimised for B. napus was
synthesized by Geneart. A genetic construct designated
35S:Musmu-MGAT2 was made by inserting the entire coding region of
1022341_MusmuMGAT2, contained within an EcoRI fragment, into
pJP3343 at the EcoRI site, generating pJP3347. Cloning of the
35S:Arath-WRI1 construct is described in Example 11. Transient
expression in N. benthamiana leaf tissue was performed as described
in Example 1.
[1488] When the mouse MGAT2 and the A. thaliana WRI1 transcription
vector were coexpressed, average N. benthamiana leaf TAG levels
were increased by 3.3-fold compared to the expression of WRI1 alone
(Table 13). In addition, the expression of the two genes resulted
in a small (29%) synergistic effect on the accumulation of leaf
TAG. The TAG level obtained with the MGAT2 gene in the presence of
WRI1 was 3.78% as quantified by Iatroscan (FIG. 12). The similar
results obtained with the animal MGAT2 and plant DGAT1
acyltransferases in combination with the A. thaliana WRI1 suggests
that a synergistic effect might be a general phenomenon when WRI
and acyltransferases are overexpressed in non-oil accumulating
vegetative plant tissues.
[1489] The experiment was repeated to introduce constructs for
expressing V2+MGAT2 compared to V2+MGAT2+WRI1, such that
infiltrated leaf samples were pooled across three leaves from the
same plant, for two plants each. In total, each combination
therefore had 6 replicate infiltrations. This yielded a smaller
standard deviation than pooling leaf samples between different
plants as was done in the first experiments. The data from this
experiment is shown in Table 14. Earlier results (Table 13) were
confirmed. Although absolute TAG levels are different (inherent to
the Benth assay and also different pooling of samples), relative
increase in TAG when WRI1 is co-expressed with V2+MGAT2 are similar
(2.45- and 2.65-fold).
Example 13. Constitutive Expression of a Monoacylglycerol
Acyltransferase, Diacylglycerol Acyltransferase and WRI1
Transcription Factor in Plant Cells
[1490] The genes coding for the A. thaliana diacylglycerol
acyltransferase DGAT1, the mouse monoacylglycerol acyltransferase
MGAT2 and the A. thaliana WRI1 were expressed in different
combinations in N. benthamiana leaf tissue according to the
transient expression system as described in Example 1. A detailed
description of the different constructs can be found in Examples 11
and 12.
[1491] The combined expression of the DGAT1, WRI1 and MGAT2 genes
resulted in an almost 3-fold further average TAG increase when
compared to the expression of the latter two (Table 15). The
maximum observed TAG yield obtained was 7.28% as quantified by
latroscan (FIG. 12). Leaf TAG levels were not significantly
affected when the gene of the mouse MGAT2 acyltransferase was left
out this combination. Results described in Example 16, however,
clearly demonstrated the positive effect of the mouse MGAT2 on the
biosynthesis of neutral lipids in N. benthamiana leaves when
expressed in combination with WRI1, DGAT1 and the Sesamum indicum
oleosin protein.
TABLE-US-00014 TABLE 13 TAG levels in triplicate Nicotiana
benthamiana leaf tissue transiently transformed with 35S:V2,
35S:MGAT2 and 35S:WRI1. Control TAG (% Genes TAG (% dry combination
dry weight).sup.1 expressed weight).sup.1 Ratio.sup.2 V2, WRI1 0.93
.+-. 0.37 V2, WRI1, 2.88 .+-. 0.56 3.30 .+-. 0.85 MGAT2 V2, MGAT2
1.56 .+-. 0.76 V2, WRI1, 3.15 .+-. 1.05 2.45 .+-. 1.73 MGAT2
.sup.1Average of three different infiltrated leaves as quantified
by latroscan .sup.2Average ratio based on side-by-side comparisons
on the same leaves
TABLE-US-00015 TABLE 14 TAG content of infiltrated N benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 + MGAT2
0.34 .+-. 0.04 2.65 V2 + MGAT2 + WRI1 0.9 .+-. 0.19
TABLE-US-00016 TABLE 15 TAG levels in triplicate Nicotiana
benthamiana leaf tissue transiently transformed with 35S:V2,
35S:MGAT2, 35S:DGAT1 and 35S:WRI1. TAG TAG Control combination (%
dry weight) .sup.1 Genes expressed (% dry weight) .sup.1 Ratio
.sup.2 V2, WRI1, DGAT1 3.35 .+-. 0.29 V2, WRI1, MGAT2, 3.15 .+-.
0.49 0.94 .+-. 0.01 DGAT1 V2, WRI1, MGAT2 1.72 .+-. 0.56 V2, WRI1,
MGAT2, 4.62 .+-. 0.47 2.88 .+-. 0.90 DGAT1 .sup.1 Average of three
different infiltrated leaves as quantified by Iatroscan .sup.2
Average ratio based on side-by-side comparisons on the same
leaves
[1492] Additional data was obtained from a further experiment where
leaf samples were pooling across leaves within same plant, 6
replicates of each. The data is shown in Table 16.
TABLE-US-00017 TABLE 16 TAG content of infiltrated N. benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 + MGAT2
+ DGAT1 1.08 .+-. 0.1 2.06 V2 + MGAT2 + DGAT1 + WRI1 2.22 .+-.
0.31
Example 14. Constitutive Expression of a Monoacylglycerol
Acyltransferase. Diacycerol Acyltransferase, WRI1 Transcription
Factor and Glycerol-3-Phosphate Acyltransferase in Plant Cells
[1493] A 35S:GPAT4 genetic construct was made by cloning the A.
thaliana GPAT4 gene (Zheng et al., 2003) from total RNA isolated
from developing siliques, followed by insertion as an EcoRI
fragment into pJP3343 resulting in pJP3344. Other constructs are
described in Examples 11 and 12. Transient expression in N.
benthamiana leaf tissue was performed as described in Example
1.
[1494] Transient expression of the A. thaliana GPAT4
acyltransferase in combination with MGAT2, DGAT1 and WRI1 led to a
small decrease in the N. benthamiana leaf TAG content as quantified
by latroscan (Table 17). The TAG level (5.78%) was also found to be
lower when GPAT4 was included in the infiltration mixture (FIG.
12). However, this finding does not rule out the hypothesis of
sn2-MAG synthesis from G3P as catalysed by the GPAT4
acyltransferase. Rather, it suggests that this catalytic step is
unlikely to be rate limiting in leaf tissue due to the high
expression levels of the endogenous GPAT4 gene (Li et al., 2007).
Moreover, the A. thaliana GPAT8 acyltransferase displays a similar
expression profile as GPAT4 and has been shown to exhibit an
overlapping function (Li et al., 2007). In developing seeds the
expression levels of GPAT4 and GPAT8 are low. As a result,
coexpression of GPAT4 in a seed context might be crucial to ensure
sufficient sn2-MAG substrate for a heterologous expressed MGAT
acyltransferase.
TABLE-US-00018 TABLE 17 TAG levels in triplicate Nicotiana
benthamiana leaf tissue transiently transformed with 35S:V2,
35S:MGAT2, 35S:DGAT1, 35S:WRI1 and 35S:GPAT4. TAG TAG Control
combination (% dry weight) .sup.1 Genes expressed (% dry weight)
.sup.1 Ratio .sup.2 V2, WRI1, MGAT2, 4.14 .+-. 0.82 V2, WRI1,
MGAT2, 3.11 .+-. 0.20 0.77 .+-. 0.13 DGAT1 DGAT1, GPAT4 V2, WRI1,
DGAT1, 2.76 .+-. 0.74 V2, WRI1, MGAT2, 4.05 .+-. 1.24 1.47 .+-.
0.22 GPAT4 DGAT1, GPAT4
[1495] Additional data was obtained from a further experiment where
leaf samples were pooling across leaves within same plant, 6
replicates of each. The data is shown in Table 18.
TABLE-US-00019 TABLE 18 TAG content of infiltrated N. benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 + MGAT2
+ DGAT1 1.54 .+-. 0.36 1.01 V2 + MGAT2 + DGAT1 + GPAT4 1.56 .+-.
0.18
Example 15. Constitutive Expression of a Monoacylglycerol
Acyltransferase, Diacycerol Acyltransferase, WRI1 Transcription
Factor and AGPase-hpRNAi Silencing Construct in Plant Cells
[1496] A DNA fragment corresponding to nucleotides 595 to 1187 of
the mRNA encoding the Nicotiana tabacum AGPase small subunit
(DQ399915) (Kwak et al., 2007) was synthesized. The 593 bp
1118501_NtAGP fragment was first cut with NcoI, treated with DNA
polymerase I large (Klenow) fragment to generate 5' blunt ends and
finally digested with XhoI. Similarly, the pENTR11-NCOI entry
vector was first digested with BamHI, treated with DNA polymerase I
large (Klenow) fragment and cut with XhoI. Ligation of the
1118501_NtAGP insert into pENTR11-NCOI generated the
pENTR11-NCOI-NtAGP entry clone. LR recombination between the
pENTR11-NCOI-NtAGP entry clone and the pHELLSGATE12 destination
vector generated pTV35, a binary vector containing the NtAGPase
RNAi cassette under the control of the 35S promotor. Other
constructs are described in Examples 11 and 12. Transient
expression in N. benthamiana leaf tissue was performed as described
in Example 1.
[1497] Expression of the N. tabacum AGPase silencing construct
together with the genes coding for MGAT2 and WRI resulted in a
1.7-fold increase in leaf TAG levels as quantified by latroscan
(Table 19). In the absence of the MGAT2 acyltransferase TAG levels
dropped almost 3-fold. Therefore the observed TAG increase cannot
be attributed solely to the silencing of the endogenous N.
benthamiana AGPase gene. Surprisingly, substituting MGAT2 for the
A. thaliana DGAT1 did not alter TAG levels in infiltrated N.
benthamiana leaves in combination with the N. tabacum AGPase
silencing construct. Silencing of the N. benthamiana AGPase
therefore appears to have a different metabolic effect on MGAT and
DGAT acyltransferases. A similar difference is also observed in the
maximum observed TAG levels with WRI1 and the AGPase silencing
construct in combination with MGAT2 or DGAT1 yielding 6.16% and
5.51% leaf oil respectively (FIG. 12).
TABLE-US-00020 TABLE 19 TAG levels in triplicate Nicotiana
benthamiana leaf tissue transiently transformed with 35S:V2,
35S:MGAT2, 35S:DGAT1, 35S:WRI1 and 35S:AGPase-hpRNAi TAG TAG
Control combination (% dry weight) .sup.1 Genes expressed (% dry
weight) .sup.1 Ratio .sup.2 V2, WRI1, MGAT2 2.33 .+-. 1.23 V2,
WRI1, MGAT2, 3.60 .+-. 0.98 1.69 .+-. 0.40 AGPase-hpRNAi V2, WRI1,
AGPase- 1.86 .+-. 0.20 V2, WRI1, MGAT2, 5.21 .+-. 1.48 2.87 .+-.
1.01 hpRNAi AGPase-hpRNAi V2, WRI1, DGAT1 4.99 .+-. 0.95 V2, WRI1,
DGAT1, 4.77 .+-. 0.79 0.96 .+-. 0.07 AGPase-hpRNAi .sup.1 Average
of three different infiltrated leaves as quantified by Iatroscan;
.sup.2 Average ratio based on side-by-side comparisons on the same
leaves
[1498] Overexpression of WRI1 and MGAT in combination with AGPase
silencing is particularly promising to increase oil yields in
starch accumulating tissues. Examples include tubers such as for
potatoes, and the endosperm of cereals, potentially leading to
cereals with increased grain oil content (Barthole et al., 2011).
Although N. tabacum and N. benthamiana AGPase genes are likely to
bear significant sequence identity, it is likely that a N.
benthamiana AGPase-hpRNAi construct will further elevate TAG yields
due to improved silencing efficiency.
[1499] Additional data was obtained from a further experiment where
leaf samples were pooled across leaves within same plant, 6
replicates of each. The data is shown in Tables 19 and 20.
TABLE-US-00021 TABLE 20 TAG content of infiltrated N. benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 + MGAT2
+ DGAT1 + 1.93 .+-. 0.18 1.14 WRI1 + Oleosin V2 + MGAT2 + DGAT1 +
2.19 .+-. 0.19 WRI1 + Oleosin + AGPase- hpRNAi
Example 16. Constitutive Expression of a Monoacylglycerol
Acyltransferase, Diacycerol Acyltransferase, WRI1 Transcription
Factor and an Oleosin Protein in Plant Cells
[1500] A pRSh1 binary vector containing the gene coding for the S.
indicum seed oleosin (Scott et al., 2010) under the control of the
35S promotor was provided by Dr. N. Roberts (AgResearch Limited,
New Zealand). Other constructs are described in Examples 11 and 12.
Transient expression in N. benthamiana leaf tissue was performed as
described in Example 1.
[1501] When the sesame oleosin protein was expressed together with
the A. thaliana WRI transcription factor and M. musculus MGAT2
acyltransferase, TAG levels in N. benthamiana leaves as quantified
by latroscan were found to be 2.2-fold higher (Table 21). No
significant changes in the leaf TAG fatty acid profiles were
detected (Table 22). A small increase in TAG was also observed when
the A. thaliana DGAT1 acyltransferase was included. Compared to the
V2 negative control, the combined expression of WRI1, DGAT1 and the
sesame oleosin protein resulted in a 3-fold TAG increase and a
maximum observed TAG level of 7.72% (Table 21 and FIG. 12). Leaf
TAG levels were further elevated by a factor of 2.5 upon including
the MGAT2 acyltransferase. This corresponded to an average of 5.7%
and a maximum observed of 18.8% TAG on a dry weight basis. The
additional increase in leaf TAG when MGAT2 was included clearly
demonstrates the positive effect of this acyltransferase on the
biosynthesis and accumulation of neutral lipids in transgenic leaf
tissues.
[1502] The experiment was repeated with the combination of genes
for expressing V2 and V2+MGAT2+DGAT1+WRI1+Oleosin, tested in
different N. benthamiana plants, with samples pooled across leaves
from the same plant and with 12 replicate infiltrations for each.
The data is shown in Table 23. Replicate samples were also pooled
across leaves from same plant, with 6 repeats for each
infiltration: The data is shown in Tables 24 and 25.
[1503] Although infiltration of N. benthamiana leaves resulted in
increased levels of leaf oil (TAG), no significant increase in the
total lipid content was detected, suggesting that a redistribution
of fatty acids from different lipids pools into TAG was occurring.
In contrast, when the MGAT2 gene was coexpressed with the DGAT1,
WRI1 and oleosin genes, total lipids were increased 2.21-fold,
demonstrating a net increase in the synthesis of leaf lipids.
Example 17. Constitutive Expression of a Monoacylglycerol
Acyltransferase, Diacylglycerol Acyltransferase, WRI1 Transcription
Factor and a FAD2-hpRNAi Silencing Construct in Plant Cells
[1504] A N. benthamiana FAD2 RNAi cassette under the control of a
35S promotor was obtained by LR recombination into the pHELLSGATE8
destination vector to generate vector pFN033. Other constructs are
described in Examples 11 and 12.
TABLE-US-00022 TABLE 21 TAG levels in triplicate Nicotiana
benthamiana leaf tissue transiently transformed with 35S:V2,
35S:MGAT2, 35S:DGAT1, 35S:WRI1 and 35S:Oleosin. TAG TAG Control
combination (% dry weight) .sup.1 Genes expressed (% dry weight)
.sup.1 Ratio .sup.2 V2, WRI1, MGAT2 1.77 .+-. 0.75 V2, WRI1, MGAT2,
3.34 .+-. 0.19 2.20 .+-. 1.10 Oleosin V2, WRI1, Oleosin 1.31 .+-.
0.19 V2, WRI1, MGAT2, 2.36 .+-. 1.10 1.79 .+-. 0.84 Oleosin V2,
WRI1, DGAT1 4.82 .+-. 1.67 V2, WRI1, DGAT1, 6.02 .+-. 1.57 1.32
.+-. 0.43 Oleosin V2, WRI1, MGAT2, 5.17 .+-. 1.87 V2, WRI1, MGAT2,
6.34 .+-. 1.74 1.25 .+-. 0.11 DGAT1 DGAT1, Oleosin V2, WRI1, DGAT1,
4.61 .+-. 1.83 V2, WRI1, MGAT2, 5.48 .+-. 1.39 1.24 .+-. 0.26
Oleosin DGAT1, Oleosin V2 1.46 .+-. 0.67 V2, WRI1, DGAT1, 3.71 .+-.
1.50 3.00 .+-. 1.63 Oleosin V2 0.90 .+-. 0.43 V2, WRI1, MGAT2, 5.74
.+-. 0.22 7.45 .+-. 3.52 DGAT1, Oleosin .sup.1 Average of three
different infiltrated leaves as quantified by Iatroscan .sup.2
Average ratio based on side-by-side comparisons on the same
leaves
TABLE-US-00023 TABLE 22 TAG fatty acid profiles of triplicate
Nicotiana benthamiana leaf tissue transiently transformed with
35S:V2, 35S:MGAT2, 35S:DGAT1, 35S:WRI1 and 35S:Oleosin. V2, WRI1,
V2, WRI1, V2, WRI1, V2, WRI1, MGAT2, Fatty acid DGAT1 DGAT1,
Oleosin MGAT2, DGAT1 DGAT1, Oleosin C14:0 0.05 .+-. 0.04 0.02 .+-.
0.04 0.05 .+-. 0.05 0.04 .+-. 0.04 C14:1.sup..DELTA.9 0.14 .+-.
0.03 0.10 .+-. 0.09 0 0 C16:0 30.64 .+-. 1.32 29.96 .+-. 1.23 25.53
.+-. 2.30 23.74 .+-. 1.83 C16:1.sup..DELTA.9 0.39 .+-. 0.17 0.32
.+-. 0.33 0.19 .+-. 0.02 0.36 .+-. 0.10 C18:0 9.85 .+-. 0.34 10.23
.+-. 0.20 8.50 .+-. 1.42 8.30 .+-. 0.73 C18:1.sup..DELTA.9 38.17
.+-. 1.28 39.01 .+-. 1.87 35.14 .+-. 6.58 38.64 .+-. 5.12
C18:1.sup..DELTA.11 0.66 .+-. 0.04 0.74 .+-. 0.20 0.53 .+-. 0.06
0.56 .+-. 0.02 C18:2.sup..DELTA.9, 12 11.58 .+-. 0.52 11.53 .+-.
0.86 16.48 .+-. 1.40 15.75 .+-. 1.58 C18:3.sup..DELTA.9, 12, 15
3.80 .+-. 0.32 3.97 .+-. 0.29 9.35 .+-. 0.74 9.61 .+-. 0.87 C20:0
2.50 .+-. 0.20 2.41 .+-. 0.15 2.17 .+-. 0.42 1.64 .+-. 0.11 C22:0
1.33 .+-. 0.21 1.16 .+-. 0.11 1.22 .+-. 0.22 0.80 .+-. 0.04 C24:0
0.90 .+-. 0.19 0.55 .+-. 0.48 0.85 .+-. 0.23 0.55 .+-. 0.06
TABLE-US-00024 TABLE 23 TAG content of infiltrated N. benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 0.19
.+-. 0.05 18.74 V2 + MGAT2 + DGAT1 + 3.56 .+-. 0.86 WRI1 +
Oleosin
TABLE-US-00025 TABLE 24 TAG content of infiltrated N. benthamiana
leaf samples. Gene combination TAG (% dry weight) Ratio V2 + MGAT2
+ DGAT1 + WRI1 2.17 .+-. 0.30 0.79 V2 + MGAT2 + DGAT1 + 2.11 .+-.
0.20 WRI1 + Oleosin V2 + MGAT2 0.32 .+-. 0.06 2.19 V2 + MGAT2 +
Oleosin 0.70 .+-. 0.17
TABLE-US-00026 TABLE 25 Total fatty acid content of infiltrated N.
benthamiana leaf samples. V2 3.12 .+-. 0.14 1 V2 + MGAT2 3.28 .+-.
0.33 1.05 V2 + MGAT2 + DGAT1 + WRI1 + Oleosin 6.88 .+-. 0.37
2.21
[1505] The genes coding for the mouse monoacylglycerol
acyltransferase MGAT2, A. thaliana diacylglycerol acyltransferase
DGAT1, A. thaliana WRI1 and a N. benthamiana FAD2 .DELTA.12-fatty
acid desaturase hairpin RNAi construct (Wood et al., manuscript in
preparation) were expressed in combination in N. benthamiana leaf
tissue using the transient expression system as described in
Example 1.
[1506] Similar changes were observed in the fatty acid compositions
of TAG, polar lipids and TFA of N. benthamiana leaves infiltrated
with WRI1, MGAT2, DGAT1 and the Fad2 silencing contruct (Tables
26-28). In all three lipid fractions, oleic acid levels were
further increased and reached almost 20% in polar lipids, 40% in
TFA and more than 55% in TAG. This increase came mostly at the
expense of linoleic acid reflecting the silencing effect on the
endoplasmic reticulum FAD2 .DELTA.12-desaturase. Leaf TAG also
contained less .alpha.-linolenic acid while levels in TFA and polar
lipids were unaffected.
[1507] When these experiments were repeated and the fatty acid
compositions determined for TAG, polar lipids and total lipids, the
results (Table 29) were consistent with the first experiment.
TABLE-US-00027 TABLE 26 TAG fatty acid profiles of triplicate
Nicotiana benthamiana leaf tissue transiently transformed with
35S:V2, 35S:MGAT2, 35S:DGAT1, 35S:WRI1 and 35S:FAD2-hpRNAi. V2,
WRI1, V2, WRI1, MGAT2, MGAT2, DGAT1, FAD2- Fatty acid V2 DGAT1
hpRNAi C14:1.sup..DELTA.9 0.28 .+-. 0.48 0.14 .+-. 0.12 0.08 .+-.
0.13 C16:0 22.73 .+-. 0.40 22.63 .+-. 1.43 19.11 .+-. 1.62
C16:1.sup..DELTA.9 0 0.28 .+-. 0.02 0.51 .+-. 0.11 C18:0 7.31 .+-.
1.44 5.27 .+-. 0.19 5.05 .+-. 0.11 C18:1.sup..DELTA.9 29.87 .+-.
11.91 32.21 .+-. 4.73 55.21 .+-. 1.31 C18:1.sup..DELTA.11 0 0.80
.+-. 0.04 0.89 .+-. 0.04 C18:2.sup..DELTA.9, 12 13.36 .+-. 3.22
20.23 .+-. 3.36 3.61 .+-. 0.18 C18:3.sup..DELTA.9, 12, 15 25.03
.+-. 10.14 15.18 .+-. 0.89 12.03 .+-. 0.72 C20:0 0.99 .+-. 0.86
1.38 .+-. 0.07 1.41 .+-. 0.04 C20:1.sup..DELTA.11 0 0.39 .+-. 0.05
0.62 .+-. 0.02 C22:0 0 0.85 .+-. 0.04 0.83 .+-. 0.05 C24:0 0.44
.+-. 0.76 0.64 .+-. 0.08 0.66 .+-. 0.05
TABLE-US-00028 TABLE 27 Fatty acid profiles of polar lipids
isolated from triplicate Nicotiana benthamiana leaf tissue
transiently transformed with 35S:V2, 35S:MGAT2, 35S:DGAT1, 35S:WRI1
and 35S:FAD2-hpRNAi. V2, WRI1, V2, WRI1, MGAT2, MGAT2, DGAT1, FAD2-
Fatty acid V2 DGAT1 hpRNAi C14:1.sup..DELTA.9 0.13 .+-. 0.23 0.17
.+-. 0.15 0 C16:0 15.00 .+-. 0.30 15.99 .+-. 0.14 15.28 .+-. 0.31
C16:1.sup..DELTA.9 2.66 .+-. 0.28 1.97 .+-. 0.40 2.09 .+-. 0.16
C18:0 2.47 .+-. 0.14 2.05 .+-. 0.18 1.95 .+-. 0.09
C18:1.sup..DELTA.9 5.12 .+-. 2.22 10.57 .+-. 1.99 18.99 .+-. 0.76
C18:1.sup..DELTA.11 0.28 .+-. 0.24 0.61 .+-. 0.01 0.67 .+-. 0.03
C18:2.sup..DELTA.9, 12 10.26 .+-. 0.96 12.39 .+-. 1.33 5.20 .+-.
0.32 C18:3.sup..DELTA.9, 12, 15 63.90 .+-. 1.18 55.70 .+-. 1.26
55.65 .+-. 1.23 C20:0 0.09 .+-. 0.15 0.19 .+-. 0.16 0.08 .+-. 0.14
C20:1.sup..DELTA.11 0 0 0 C22:0 0 0.17 .+-. 0.15 0 C24:0 0.09 .+-.
0.15 0.19 .+-. 0.16 0.09 .+-. 0.16
TABLE-US-00029 TABLE 28 Fatty acid profiles of total lipids
isolated from triplicate Nicotiana benthamiana leaf tissue
transiently transformed with 35S:V2, 35S:MGAT2, 35S:DGAT1, 35S:WRI1
and 35S:FAD2-hpRNAi. V2, WRI1, V2, WRI1, MGAT2, MGAT2, DGAT1, FAD2-
Fatty acid V2 DGAT1 hpRNAi C14:1.sup..DELTA.9 0.53 .+-. 0.08 0.27
.+-. 0.02 0.26 .+-. 0.02 C16:0 16.00 .+-. 1.05 19.70 .+-. 0.63
17.30 .+-. 0.72 C16:1.sup..DELTA.9 2.02 .+-. 0.62 0.24 .+-. 0.02
0.28 .+-. 0.02 C18:0 3.75 .+-. 0.25 4.33 .+-. 0.09 4.17 .+-. 0.03
C18:1.sup..DELTA.9 11.12 .+-. 6.77 23.32 .+-. 4.09 40.37 .+-. 2.24
C18:1.sup..DELTA.11 0.46 .+-. 0.08 0.69 .+-. 0.03 0.75 .+-. 0.01
C18:2.sup..DELTA.9, 12 11.14 .+-. 0.83 17.28 .+-. 2.34 4.56 .+-.
0.29 C18:3.sup..DELTA.9, 12, 15 53.27 .+-. 7.34 32.43 .+-. 1.49
30.43 .+-. 1.34 C20:0 0.51 .+-. 0.16 0.93 .+-. 0.05 0.92 .+-. 0.03
C20:1.sup..DELTA.11 0 0.26 .+-. 0.03 0.40 .+-. 0.02 C22:0 0.83 .+-.
0.24 0.36 .+-. 0.06 0.37 .+-. 0.04 C24:0 0.38 .+-. 0.09 0.19 .+-.
0.03 0.20 .+-. 0.02
TABLE-US-00030 TABLE 29 Fatty acid composition of TAG, Polar lipids
and total lipids in infiltrated N. benthamiana leaf samples. TAG
Polar lipids Total lipids V2 + MGAT2 + V2 + MGAT2 + V2 + MGAT2 + V2
+ MGAT2 + V2 + MGAT2 + V2 + MGAT2 + DGAT1 + DGAT1 + WRI1 + DGAT1 +
DGAT1 + DGAT1 + DGAT1 + WRI1 + WRI1 + Oleosin + WRI1 + WRIT +
Oleosin + WRI1 + Oleosin + Oleosin FAD2-hpRNAi Oleosin FAD2-hpRNAi
Oleosin FAD2-hpRNAi C14:0 0.00 0.00 0.00 0.00 0.06 .+-. 0.03 0.02
.+-. 0.03 C14:1.sup..DELTA.9 0.00 0.00 0.05 .+-. 0.12 0.00 0.24
.+-. 0.03 0.19 .+-. 0.10 C16:0 19.63 .+-. 0.53 16.95 .+-. 1.13
15.85 .+-. 1.17 16.42 .+-. 2.11 16.88 .+-. 0.92 15.45 .+-. 1.24
C16:1.sup..DELTA.13t 0.00 0.15 .+-. 0.16 2.31 .+-. 0.38 1.61 .+-.
0.85 1.03 .+-. 0.23 0.85 .+-. 0.23 C16:3.sup..DELTA.7, 12, 15 0.00
0.00 7.54 .+-. 0.40 7.42 .+-. 0.59 3.25 .+-. 0.47 2.79 .+-. 0.43
C18:0 6.64 .+-. 1.35 6.99 .+-. 0.43 2.88 .+-. 0.13 2.41 .+-. 1.21
5.36 .+-. 0.15 5.40 .+-. 0.18 C18:1.sup..DELTA.9 29.45 .+-. 3.65
53.97 .+-. 1.51 8.56 .+-. 2.04 19.68 .+-. 1.32 20.59 .+-. 3.52
39.27 .+-. 2.28 C18:1.sup..DELTA.11 0.59 .+-. 0.29 0.68 .+-. 0.34
0.45 .+-. 0.22 0.40 .+-. 0.31 0.59 .+-. 0.03 0.66 .+-. 0.05
C18:2.sup..DELTA.9, 12 23.47 .+-. 1.18 5.29 .+-. 0.37 13.13 .+-.
0.32 4.72 .+-. 2.33 18.35 .+-. 0.70 5.56 .+-. 0.28
C18:3.sup..DELTA.9,12, 15 18.32 .+-. 5.48 12.84 .+-. 0.60 49.04
.+-. 2.78 47.22 .+-. 5.40 30.03 .+-. 3.51 26.28 .+-. 3.07 C20:0
1.12 .+-. 0.56 1.56 .+-. 0.04 0.19 .+-. 0.21 0.11 .+-. 0.17 0.88
.+-. 0.06 1.03 .+-. 0.07 C20:1.sup..DELTA.11 0.00 0.20 .+-. 0.22
0.00 0.00 0.08 .+-. 0.08 0.22 .+-. 0.11 C22:0 0.57 .+-. 0.28 0.81
.+-. 0.07 0.00 0.00 0.54 .+-. 0.05 0.61 .+-. 0.07 C22:1 0.00 0.00
0.00 0.00 0.50 .+-. 0.03 0.22 .+-. 0.24 C22:2n6 0.00 0.00 0.00 0.00
0.80 .+-. 0.14 0.77 .+-. 0.13 C24:0 0.21 .+-. 0.32 0.57 .+-. 0.29
0.00 0.00 0.42 .+-. 0.01 0.48 .+-. 0.03 C24:1 0.00 0.00 0.00 0.00
0.42 .+-. 0.05 0.18 .+-. 0.2
Example 18. Expression of Mus musculus MGAT1 and MGAT2 in Nicotiana
Benthamiana Cells by Stable Transformation
[1508] Constitutive Expression in N. benthamiana
[1509] The enzyme activity of the M. musculus MGAT1 and MGAT2 was
demonstrated in Nicotiana benthamiana. The chimeric vectors
35S:Musmu-MGAT1 and 35S:Musmu-MGAT2 were introduced into A.
tumefaciens strain AGL1 via standard electroporation procedure and
grown on solid LB media supplemented with kanamycin (50 mg/L) and
rifampicin (25 mg/L) and incubated at 28.degree. C. for two days. A
single colony was used to initiate fresh culture. Following 48
hours culturing with vigorous aeration, the cells were collected by
centrifugation at 2,000.times.g and the supernatant were removed.
The cells were resuspended in a new solution containing 50% LB and
50% MS medium at the density of OD.sub.600=0.5. Leaf samples of
Nicotiana benthamiana plants grown asceptically in vitro were
excised and cut into square sections around 0.5-1 cm.sup.2 in size
with a sharp scalpel while immersed in the A. tumefaciens solution.
The wounded N. benthamiana leaf pieces submerged in A. tumefaciens
were allowed to stand at room temperature for 10 min prior to being
blotted dry on a sterile filter paper and transferred onto MS
plates without supplement. Following a co-cultivation period of two
days at 24.degree. C., the explants were washed three times with
sterile liquid MS medium, and finally blot dry with sterile filter
paper and placed on the selective agar-solidified MS medium
supplemented with 1.0 mg/L bencylaminopurine (BAP), 0.25 mg/L
indoleacetic acid (IAA), 50 mg/L kanamycin and 250 mg/L cefotaxime
and incubated at 24.degree. C. for two weeks to allow for shoot
development from the transformed N. benthamiana leaf discs. To
establish in vitro transgenic plants, healthy green shoots were cut
off and transferred onto a new 200 mL tissue culture pots
containing agar-solidified MS medium supplemented with .mu.g/L IAA
and 50 mg/L kanamycin and 250 mg/L cefotaxime.
[1510] Expression of the MGAT1 and MGAT2 transgenes was determined
by Real-Time PCR. Highly-expressing lines were selected and their
seed harvested. This seed was planted directly onto soil and the
segregating population of seedlings harvested after four weeks.
Highly-expressing events were selected and seed produced by these
planted out directly onto soil to result in a segregating
population of 30 seedlings. After three weeks leaf discs were taken
from each seedling for DNA extraction and subsequent PCR to
determine which lines were transgenic and which were null for the
transgene. The population was then harvested with the entire aerial
tissue from each seedling cleaned of soil and freeze-dried. The dry
weight of each sample was recorded and total lipids isolated. The
TAG in these total lipid samples was quantified by TLC-FID and the
ratio of TAG to an internal standard (DAGE) in each sample
determined (FIG. 14). The average level of TAG in the transgenic
seedlings of 35S:Musmu-MGAT2 line 3347-19 was found to be 4.1-fold
higher than the average level of TAG in the null seedlings. The
event with the largest increase in TAG had 7.3-fold higher TAG than
the average of the null events.
Constitutive Expression in A. thaliana
[1511] The enzyme activity of the M. musculus MGAT1 and MGAT2 was
demonstrated in A. thaliana. The chimeric vectors 35S:Musmu-MGAT1
and 35S:Musmu-MGAT2 along with the empty vector control pORE04 were
transformed in A. thaliana by the floral dip method and seed from
primary transformants selected on kanamycin media. The T2 seed from
these T1 plants was harvested and TFA of the seeds from each plant
determined (FIG. 15). The average mg TFA/g seed was found to be
139.+-.13 for the control pORE04 lines with median 136.0, 152.+-.14
for the 35S:MGAT1 lines with median 155.1 and 155.+-.11 for the
35S:MGAT2 lines with median 154.7. This represented an average TFA
increase compared to the control of 9.7% for 35S:MGAT1 and 12.1%
for 35S:MGAT2.
Example 19. Additional Genes
Further Increases in Oil
[1512] Additional genes are tested alongside the combinations
described above to determine whether further oil increases can be
achieved. These include the following Arabidopsis genes: AT4G02280,
Sucrose synthase SUS3; AT2G36190, Invertase CWINV4; AT3G13790,
Invertase CWINV1; AT1G61800, Glucose 6 phosphate:phosphate
translocator GPT2; AT5G33320, Phosphoenolpyruvate transporter PPT1;
AT4G15530, Pyruvate orthophosphate dikinase Plastid-PPDK;
AT5G52920, Pyruvate kinase pPK-P1. The genes coding for these
enzymes are synthesised and cloned into the constitutive binary
expression vector pJP3343 as EcoRI fragments for testing in N.
benthamiana.
[1513] When a number of genes were added to the combination of
WRI1, DGAT1, MGAT2 and oleosin and expressed in N. benthamiana
leaves, no additional increase in the level of TAG was observed,
namely for. safflower PDAT, Arabidopsis thaliana PDAT1, Arabidopsis
thaliana DGAT2, Arabidopsis thaliana caleosin, peanut oleosin,
Arabidopsis thaliana haemoglobin 2, Homo sapiens iPLAh, Arabidopsis
thaliana GPAT4, E. coli G3P dehydrogenase, yeast G3P dehydrogenase,
castor LPAAT2, Arabidopsis thaliana beta-fructofuranosidase
(ATBFRUCT1, NM_112232), Arabidopsis thaliana
beta-fructofiranosidase (cwINV4, NM_129177), indicating that none
of these enzyme activities were rate limiting in N. benthamiana
leaves when expressed transiently. This does not indicate that they
will have no effect in stably-transformed plants, such as in seed,
or in other organisms.
[1514] Further additional genes are tested for additive or
synergistic oil increase activity. These include the following
Arabidopsis thaliana gene models or their encoded proteins, and
homologues from other species, which are grouped by putative
function and have previously been shown to be upregulated in
tissues with increased oil content. Genes/proteins involved in
sucrose degradation: AT1G73370, AT3G43190, AT4G02280, AT5G20830,
AT5G37180, AT5G49190, AT2G36190, AT3G13784, AT3G13790, AT3G52600.
Genes/proteins involved in the oxidative pentose phosphate pathway:
AT3G27300, AT5G40760, AT1G09420, AT1G24280, AT5G13110, AT5G35790,
AT3G02360, AT5G41670, AT1G64190, AT2G45290, AT3G60750, AT1G12230,
AT5G13420, AT1G13700, AT5G24410, AT5G24420, AT5G24400, AT1G63290,
AT3G01850, AT5G61410, AT1G71100, AT2G01290, AT3G04790, AT5G44520,
AT4G26270, AT4G29220, AT4G32840, AT5G47810, AT5G56630, AT2G22480,
AT5G61580, AT1G18270, AT2G36460, AT3G52930, AT4G26530, AT2G01140,
AT2G21330, AT4G38970, AT3G55440, AT2G21170. Genes/proteins involved
in glycolysis: AT1G13440, AT3G04120, AT1G16300, AT1G79530,
AT1G79550, AT3G45090, AT5G60760, AT1G56190, AT3G12780, AT5G61450,
AT1G09780, AT3G08590, AT3G30841, AT4G09520, AT1G22170, AT1G78050,
AT2G36530, AT1G74030. Genes/proteins which function as plastid
transporters: AT1G61800, AT5G16150, AT5G33320, AT5G46110,
AT4G15530, AT2G36580, AT3G52990, AT3G55650, AT3G55810, AT4G26390,
AT5G08570, AT5G56350, AT5G63680, AT1G32440, AT3G22960, AT3G49160,
AT5G52920. Genes/proteins involved in malate and pyruvate
metabolism: AT1G04410, AT5G43330, AT5G56720, AT1G53240, AT3G15020,
AT2G22780, AT5G09660, AT3G47520, AT5G58330, AT2G19900, AT5G11670,
AT5G25880, AT2G13560, AT4G00570.
[1515] Constructs are prepared which include sequences encoding
these candidate proteins, which are infiltrated into N. benthamiana
leaves as in previous experiments, and the fatty acid content and
composition analysed. Genes which aid in increasing non-polar lipid
content are combined with the other genes as described above,
principally those encoding MGAT, Wri1, DGAT1 and an Oleosin, and
used to transform plant cells.
Increases in Unusual Fatty Acids
[1516] Additional genes are tested alongside the combinations
described above to determine whether increases in unusual fatty
acids can be achieved. These include the following genes (provided
are the GenBank Accession Nos.) which are grouped by putative
function and homologues from other species. Delta-12 acetylenases
ABC00769, CAA76158, AAO38036, AAO38032; Delta-12 conjugases
AAG42259, AAG42260, AAN87574; Delta-12 desaturases P46313,
ABS18716, AAS57577, AAL61825, AAF04093, AAF04094; Delta-12
epoxygenases XP_001840127, CAA76156, AAR23815; Delta-12
hydroxylases ACF37070, AAC32755, ABQ01458, AAC49010; and Delta-12
P450 enzymes such as AF406732.
[1517] Constructs are prepared which include sequences encoding
these candidate proteins, which are infiltrated into N. benthamiana
leaves as in previous experiments, and the fatty acid content and
composition analysed. The nucleotide sequences of the coding
regions may be codon-optimised for the host species of interest
Genes which aid in increasing unusual fatty acid content are
combined with the other genes as described above, principally those
encoding MGAT, WRI1, DGAT1 and an Oleosin, and used to transform
plant cells.
Example 20. Stable Transformation of Plants Including Nicotiana
Tabacum with Combinations of Oil Increase Genes
[1518] An existing binary expression vector, pORE04+11ABGBEC (U.S.
Provisional Patent Application No. 61/660,392), which contained a
double enhancer-region 35S promoter expressing the NPTII kanamycin
resistance gene and three gene expression cassettes, was used as a
starting vector to prepare several contructs each containing a
combination of genes for sstable transformation of plants. This
vector was modified by exchanging the expressed genes with oil
increase genes, as follows. pORE04+11ABGBEC was first modified by
inserting an intron-interrupted sesame oleosin gene, flanked by
NotI sites, from the vector pRSh1-PSP1 into the pORE04+11ABGBEC
NotI sites to generate pJP3500. pJP3500 was then modified by
inserting a codon-optimised DNA fragment encoding the A. thaliana
WRL1 gene into the EcoRI sites to generate pJP3501. pJP3501 was
further modified by inserting a DNA fragment encoding the wild-type
A. thaliana DGAT1 coding region, flanked by AsiSI sites, into the
AsiSI sites to generate pJP3502 (SEQ ID NO:409). A final
modification was made by inserting another expression cassette,
consisting of a double enhancer-region 35S promoter expressing a
coding region encoding the M. musculus MGAT2, as a StuI-ZraI
fragment into the SfoI site of pJP3502 to generate pJP3503 (SEQ ID
NO:410). The MGAT2 expression cassette was excised from pJP3347 at
the StuI+ZraI sites. pJP3502 and pJP3503 were both used to stably
transform N. tabacum as described below. By these constructions,
pJP3502 contained the A. thaliana WRL1 and DGAT1 coding regions
driven by the A. thaliana Rubisco small subunit promoter (SSU) and
double enhancer-region 35S promoter, respectively, as well as a
SSU:sesame oleosin cassette. The T-DNA region of this construct is
shown schematically in FIG. 16. The vector pJP3503 additionally
contained the e35S::MGAT2 cassette. This construct is shown
schematically in FIG. 17. The nucleotide sequence of the T-DNA
region of the construct pJP3503 is given as SEQ ID NO:412.
Stable Transformation of Nicotiana tabacum with Combinations of
Genes
[1519] The binary vectors pJP3502 and pJP3503 were separately
introduced into the A. tumefaciens strain AGL1 by a standard
electroporation procedure. Transformed cells were selected and
grown on LB-agar supplemented with kanamycin (50 mg/l) and
rifampicin (25 mg/l) and incubated at 28.degree. C. for two days. A
single colony of each was used to initiate fresh cultures in LB
broth. Following 48 hours incubation with vigorous aeration, the
cells were collected by centrifugation at 2,000 g and the
supernatant was removed. The cells were resuspended at the density
of OD.sub.600=0.5 in fresh medium consisting of 50% LB and 50% MS
medium.
[1520] Leaf samples of N. tabacum cultivar W38 grown asceptically
in vitro were excised with a scalpel and cut into pieces of about
0.5-1 cm.sup.2 in size while immersed in the A. tumefaciens
suspensions. The cut leaf pieces were left in the A. tumefaciens
suspensions at room temperature for 15 minutes prior to being
blotted dry on a sterile filter paper and transferred onto MS
plates without antibiotic supplement. Following a co-cultivation
period of two days at 24.degree. C., the explants were washed three
times with sterile, liquid MS medium, then blotted dry with sterile
filter paper and placed on the selective MS agar supplemented with
1.0 mg/L benzylaminopurine (BAP), 0.5 mg/L indoleacetic acid (IAA),
100 mg/L kanamycin and 200 mg/L cefotaxime. The plates were
incubated at 24.degree. C. for two weeks to allow for shoot
development from the transformed N. tabacum leaf pieces.
[1521] To establish rooted transgenic plants in vitro, healthy
green shoots were cut off and transferred to MS agar medium
supplemented with 25 g/L IAA, 100 mg/L kanamycin and 200 mg/L
cefotaxime. After roots had developed, individual plants were
transferred to soil and grown in the glasshouse. Leaf samples were
harvested at different stages of plant development including before
and during flowering. Total fatty acids, polar lipids and TAG were
quantified and their fatty acid profiles determined by TLC/GC as
described in Example 1.
Analysis of pJP3503 Transformants
[1522] For the transformation with pJP3503 ("4-gene construct"),
leaf samples of about 1 cm.sup.2 were taken from 30 primary
transformants prior to flower buds forming and TAG levels in the
samples were quantified by latroscan. Seven plants were selected
for further analysis, of which five displaying increased leaf oil
levels and two exhibiting oil levels essentially the same as
wild-type plants. Freeze-dried leaf samples from these plants were
analysed for total lipid content and TAG content and fatty acid
composition by TLC and GC. Transformed plants numbered 4 and 29
were found to have considerably increased levels of leaf oil
compared to the wild type, while plant number 21 exhibited the
lowest TAG levels at essentially wild-type levels (Table 30).
Plants numbered 11, 15 and 27 had intermediate levels of leaf oil.
Oleic acid levels in TAG were found to be inversely correlated to
the TAG yields, consistent with the results of the earlier
transient expression experiments in N. benthamiana.
[1523] In the transformed plants numbered 4 and 29, leaf oil
content (as a percentage of dry weight) was found to increase
considerably at the time of flowering (Table 31). From the data in
Table 31, the increase was at least 1.7- and 2.4-fold for plants 4
and 29, respectively. No such change was observed for plant 21
which had TAG levels similar to the wild-type control. Oleic acid
levels in the TAG fractions isolated from each sample followed a
similar pattern. This fatty acid accumulated up to 22.1% of the
fatty acid in TAG from plants 4 and 29, a 17-18-fold increase
compared to plant 21 and the wild-type. The increase in oleic acid
was accompanied by increased linoleic acid and palmitic acid levels
while .alpha.-linolenic acid levels dropped 8-fold compared to in
plant 21 and the wild-type control. Unlike TAG, polar lipid levels
decreased slightly at the flowering stage in the three lines (Table
32). Changes in C18 monounsaturated and polyunsaturated fatty acid
levels in the polar lipid fractions of the three lines were similar
to the shifts in their TAG composition although the changes in
oleic acid and linoleic acid were less marked. Significant
increases in total leaf lipids were observed for lines 4 and 29
during flowering with levels reaching more than 10% of dry weight
(Table 33). Total leaf lipid levels in plant 21 before and during
flowering were similar to levels observed in wild-type plants at
similar stages (Tables 33 and 35). Changes in the total lipid fatty
acid composition of all three plants were similar to the respective
TAG fatty acid compositions. Leaf oil in plant 4 during seed
setting was found to be further elevated at the onset of leaf
chlorosis. The highest leaf TAG levels detected at this stage
corresponded to a 65-fold increase compared to similar aged leaves
in plant 21 during seed setting and a 130-fold increase compared to
similar leaves of flowering wild-type plants (Table 34; FIG.
18).
[1524] The increased TAG in this plant coincided with elevated
oleic acid levels. Unlike plant 4, leaf TAG levels in the other two
primary transformants and wild-type tobacco did not increase, or
only marginally increased, after flowering and during chlorosis.
The lower leaves of plants 4 and 29 exhibited reduced TAG levels
upon senescence. In all plants, linoleic acid levels dropped while
.alpha.-linolenic acid levels were increased with progressing leaf
age.
[1525] Consistent with the increased TAG levels, total lipid levels
in leaves of plants 4 and 29 during seed setting were further
elevated compared to similar leaves of both plants during flowering
(Tables 33 and 35). The highest total lipid level detected in plant
4 on a dry weight basis was 15.8%, equivalent to a 7.6- and
11.2-fold increase compared to similar leaves of plant 21 and
wild-type plants, respectively. Whilst the fatty acid composition
of total lipid in the leaves of the wild type plant and plant 21
were similar, significant differences were observed in plants 4 and
29. These changes mirrored those found in TAG of both primary
transformants.
[1526] Intriguingly, leaves of plants 4 and 29 before and during
seed setting were characterized by a glossy surface, providing a
phenotypic change that can serve as a phenotype that is easily
scored visually, which could aid the timing of harvest for maximal
oil content.
[1527] In summary, leaves of plants 4 and 29 rapidly accumulated
TAG during flowering up till seed setting. At the latter stage, the
majority of leaves exhibited TAG levels between 7% and 13% on a dry
weight basis, compared to 0.1%-0.2% for line 21. These observed TAG
levels and total lipid levels far exceed the levels achieved by
Andrianov et al., (2010) who reported up to a maximum of 5.8% and
6.8% TAG in leaves of N. tabacum upon constitutive expression of
the A. thaliana DGAT1 and inducible expression of the A. thaliana
LEC2 genes.
TABLE-US-00031 TABLE 30 Percentage TAG (% weight of leaf dry
weight) and oleic acid levels (% of total fatty acids) in the TAG
isolated from leaves of selected primary tobacco plants transformed
with pJP3503 Development Plant No. % TAG (DW) % C18:1.sup..DELTA.9
stage of plant Wild type 0.06 2.3 Budding Wild type 0.1 1.3
Flowering 3 0.05 1.5 Budding 4 1.29 10.2 Budding 11 0.21 7.4
Flowering 15 0.23 4.5 No buds 21 0.01 1.9 No buds 27 0.19 3.3
Budding 29 1.15 10.4 No buds
TABLE-US-00032 TABLE 31 TAG levels (% weight of leaf dry weight)
and fatty acid composition of TAG isolated from wild-type and three
selected tobacco plants transformed with pJP3503, before and during
flowering. The data shown are averages and standard deviations of
2-3 independent repeats. Before flowering Flowering Wild type Plant
21 Plant 4 Plant 29 Wild type Plant 21 Plant 4 Plant 29 %/leaf DW
0.1 0.0 3.1 .+-. 0.3 4.1 .+-. 0.3 0.1 0.1 .+-. 0.0 7.3 .+-. 0.3 6.9
.+-. 0.5 C14:0 0.6 0.6 .+-. 0.2 0.1 .+-. 0.0 0.2 .+-. 0.0 0.5 0.4
.+-. 0.0 0.1 .+-. 0.0 0.1 .+-. 0.0 C16:0 9.1 15.9 .+-. 0.3 42.0
.+-. 0.5 34.9 .+-. 0.7 7.5 15.0 .+-. 0.7 33.1 .+-. 1.0 24.8 .+-.
1.4 C16:1.sup..DELTA.3t 0.0 0.4 .+-. 0.1 0.1 .+-. 0.0 0.2 .+-. 0.0
0.4 0.2 .+-. 0.0 0.1 .+-. 0.0 0.2 .+-. 0.0 C16:1.sup..DELTA.9 0.3
0.6 .+-. 0.0 3.3 .+-. 0.2 1.5 .+-. 0.1 0.3 0.6 .+-. 0.0 3.3 .+-.
0.2 1.2 .+-. 0.1 C16:3.sup..DELTA.7, 12, 15 3.7 0.8 .+-. 0.1 0.1
.+-. 0.0 0.2 .+-. 0.0 3.6 0.8 .+-. 0.1 0.1 .+-. 0.0 0.2 .+-. 0.0
C18:0 3.2 4.6 .+-. 0.4 3.0 .+-. 0.1 5.6 .+-. 0.3 2.4 3.4 .+-. 0.0
3.3 .+-. 0.1 4.6 .+-. 0.1 C18:1.sup..DELTA.9 2.3 1.2 .+-. 0.2 10.6
.+-. 0.3 10.6 .+-. 0.2 1.3 1.2 .+-. 0.2 19.1 .+-. 1.8 22.1 .+-. 2.7
C18:1.sup..DELTA.11 0.1 0.1 .+-. 0.0 2.2 .+-. 0.2 1.2 .+-. 0.1 0.1
0.1 .+-. 0.0 2.1 .+-. 0.0 0.9 .+-. 0.0 C18:2.sup..DELTA.9, 12 26.9
20.4 .+-. 1.1 20.7 .+-. 0.7 30.0 .+-. 1.0 23.7 19.5 .+-. 0.8 25.3
.+-. 0.6 34.7 .+-. 1.0 C18:3.sup..DELTA.9, 12, 15 52.6 54.0 .+-.
0.8 15.9 .+-. 0.5 11.5 .+-. 1.3 59.3 57.5 .+-. 0.4 10.8 .+-. 0.5
7.1 .+-. 0.6 C20:0 0.3 0.6 .+-. 0.0 1.0 .+-. 0.0 2.1 .+-. 0.2 0.3
0.4 .+-. 0.0 1.3 .+-. 0.0 2.0 .+-. 0.1 C20:1.sup..DELTA.11 0.1 0.0
0.0 0.2 .+-. 0.1 0.1 0.1 .+-. 0.0 0.1 .+-. 0.0 0.3 .+-. 0.0
C20:2.sup..DELTA.11, 14 0.2 0.2 .+-. 0.0 0.0 0.1 .+-. 0.0 0.2 0.3
.+-. 0.0 0.0 0.1 .+-. 0.0 C20:3.sup..DELTA.11, 14, 17 0.2 0.2 .+-.
0.0 0.0 0.0 0.1 0.2 .+-. 0.0 0.0 0.0 C22:0 0.1 0.2 .+-. 0.0 0.5
.+-. 0.0 1.0 .+-. 0.1 0.0 0.2 .+-. 0.0 0.7 .+-. 0.0 1.0 .+-. 0.0
C24:0 0.4 0.1 .+-. 0.1 0.4 .+-. 0.0 0.9 .+-. 0.1 0.3 0.1 .+-. 0.0
0.5 .+-. 0.0 0.7 .+-. 0.1
TABLE-US-00033 TABLE 32 Polar lipid levels (% weight of leaf dry
weight) and fatty acid composition of polar lipids of leaf tissue
from selected tobacco plants transformed with pJP3503, before and
during flowering. Data shown are the average and standard
deviations of 2-3 independent repeats, except for plant 21 (before
flowering). Before flowering Flowering Plant 21 Plant 4 Plant 29
Plant 21 Plant 4 Plant 29 %/leaf DW 2.0 3.3 .+-. 0.4 2.5 .+-. 0.4
1.7 .+-. 0.0 2.4 .+-. 0.0 1.7 .+-. 0.1 C14:0 0.0 0.0 0.0 0.0 0.0
0.0 C16:0 12.0 18.7 .+-. 0.6 12.7 .+-. 0.4 12.7 .+-. 0.0 16.2 .+-.
0.2 11.8 .+-. 0.2 C16:1.sup..DELTA.3t 1.6 0.5 .+-. 0.1 1.4 .+-. 0.1
1.4 .+-. 0.0 1.1 .+-. 0.2 1.4 .+-. 0.1 C16:1.sup..DELTA.9 0.1 2.0
.+-. 0.1 0.7 .+-. 0.1 0.1 .+-. 0.0 1.8 .+-. 0.1 0.5 .+-. 0.0
C16:3.sup..DELTA.7, 12, 15 7.5 2.4 .+-. 0.2 3.8 .+-. 0.1 6.3 .+-.
0.0 1.0 .+-. 0.1 3.7 .+-. 0.3 C18:0 2.1 1.1 .+-. 0.0 0.9 .+-. 0.1
2.5 .+-. 0.1 1.3 .+-. 0.0 1.4 .+-. 0.0 C18:1.sup..DELTA.9 1.1 5.6
.+-. 0.5 4.1 .+-. 0.0 1.0 .+-. 0.1 11.9 .+-. 1.1 9.2 .+-. 0.9
C18:1.sup..DELTA.11 0.1 2.2 .+-. 0.1 1.0 .+-. 0.1 0.1 .+-. 0.0 2.1
.+-. 0.1 0.6 .+-. 0.0 C18:2.sup..DELTA.9, 12 12.5 19.8 .+-. 1.0
19.7 .+-. 1.4 13.6 .+-. 0.1 27.6 .+-. 0.6 28.8 .+-. 0.5
C18:3.sup..DELTA.9, 12, 15 62.3 46.8 .+-. 0.6 55.1 .+-. 0.8 61.3
.+-. 0.1 36.0 .+-. 1.1 41.6 .+-. 0.6 C20:0 0.3 0.3 .+-. 0.0 0.2
.+-. 0.0 0.3 .+-. 0.0 0.4 .+-. 0.0 0.4 .+-. 0.0 C20:1.sup..DELTA.11
0.0 0.0 0.0 0.0 0.0 0.0 C20:2.sup..DELTA.11, 14 0.1 0.0 0.0 0.1
.+-. 0.0 0.0 0.0 C20:3.sup..DELTA.11, 14, 17 0.1 0.0 0.0 0.1 .+-.
0.0 0.0 0.0 C22:0 0.2 0.2 .+-. 0.0 0.2 .+-. 0.0 0.2 .+-. 0.0 0.3
.+-. 0.0 0.3 .+-. 0.0 C24:0 0.2 0.2 .+-. 0.0 0.3 .+-. 0.0 0.2 .+-.
0.0 0.3 .+-. 0.0 0.3 .+-. 0.0
TABLE-US-00034 TABLE 33 Total lipid levels (% weight of leaf dry
weight) and fatty acid composition of total lipids in leaves from
tobacco plants transformed with pJP3503, just before and during
flowering. Data shown are the average of 2-3 leaf samples. Before
flowering Flowering Plant 21 Plant 4 Plant 29 Plant 21 Plant 4
Plant 29 %/leaf DW 2.4 .+-. 0.2 6.9 .+-. 0.5 4.9 .+-. 1.1 2.0 .+-.
0.1 9.8 .+-. 0.3 8.8 .+-. 0.3 C14:0 0.1 .+-. 0.0 0.1 .+-. 0.0 0.1
.+-. 0.0 0.1 .+-. 0.0 0.1 .+-. 0.0 0.1 .+-. 0.0 C16:0 12.1 .+-. 0.1
27.6 .+-. 1.2 20.7 .+-. 0.6 12.7 .+-. 0.1 26.9 .+-. 0.9 20.2 .+-.
1.2 C16:1.sup..DELTA.3t 2.1 .+-. 0.2 0.4 .+-. 0.0 0.9 .+-. 0.1 2.7
.+-. 0.4 0.8 .+-. 0.1 0.7 .+-. 0.1 C16:1.sup..DELTA.9 0.0 2.6 .+-.
0.2 1.0 .+-. 0.1 0.0 2.9 .+-. 0.1 1.0 .+-. 0.0 C16:3.sup..DELTA.7,
12, 15 6.9 .+-. 0.3 1.3 .+-. 0.1 2.1 .+-. 0.1 5.6 .+-. 0.2 0.4 .+-.
0.0 0.9 .+-. 0.1 C18:0 2.2 .+-. 0.1 1.9 .+-. 0.0 2.8 .+-. 0.1 2.6
.+-. 0.1 2.6 .+-. 0.1 3.6 .+-. 0.1 C18:1.sup..DELTA.9 1.1 .+-. 0.2
7.5 .+-. 0.5 6.6 .+-. 0.0 1.1 .+-. 0.2 16.2 .+-. 1.5 17.8 .+-. 2.0
C18:1.sup..DELTA.11 0.2 .+-. 0.0 2.1 .+-. 0.1 1.1 .+-. 0.1 0.2 .+-.
0.0 2.0 .+-. 0.0 0.8 .+-. 0.0 C18:2.sup..DELTA.9, 12 13.8 .+-. 1.5
21.4 .+-. 0.7 26.5 .+-. 1.6 14.1 .+-. 0.5 27.3 .+-. 0.4 35.9 .+-.
0.5 C18:3.sup..DELTA.9, 12, 15 60.6 .+-. 1.4 33.6 .+-. 1.5 36.0
.+-. 1.0 58.5 .+-. 1.2 18.3 .+-. 0.5 15.5 .+-. 0.6 C20:0 0.3 .+-.
0.0 0.7 .+-. 0.0 1.0 .+-. 0.1 0.3 .+-. 0.0 1.0 .+-. 0.0 1.5 .+-.
0.0 C20:1.sup..DELTA.11 0.0 0.0 0.1 .+-. 0.0 0.0 0.1 .+-. 0.0 0.3
.+-. 0.0 C20:2.sup..DELTA.11, 14 0.1 .+-. 0.0 0.0 0.1 .+-. 0.0 0.2
.+-. 0.0 0.0 0.0 C20:3.sup..DELTA.11, 14, 17 0.1 .+-. 0.0 0.0 0.0
0.3 .+-. 0.0 0.6 .+-. 0.0 0.8 .+-. 0.0 C22:0 0.2 .+-. 0.0 0.3 .+-.
0.0 0.5 .+-. 0.1 1.3 .+-. 0.1 0.3 .+-. 0.0 0.2 .+-. 0.0 C24:0 0.2
.+-. 0.0 0.3 .+-. 0.0 0.5 .+-. 0.0 0.3 .+-. 0.0 0.5 .+-. 0.0 0.6
.+-. 0.0
TABLE-US-00035 TABLE 34 TAG levels (% weight of leaf dry weight)
and fatty acid composition of TAG isolated from different aged
leaves, post flowering, of three selected tobacco plants
transformed with pJP3503. Plant: .sup.a Wild type Plant 21 Plant 4
Plant 29 Leaf stage .sup.b G YG G YG G YG Y G YG Y .sup.c (%/leaf
DW 0.1 0.1 0.1 0.2 9.5 13.0 10.7 7.0 7.1 2.1 C14:0 0.5 0.3 0.4 0.3
0.2 0.1 0.1 0.2 0.2 0.3 C16:0 7.5 14.8 8.9 14.9 31.1 33.3 38.0 25.7
33.0 38.5 C16:1.sup..DELTA.3t 0.4 0.3 0.3 0.2 0.1 0.1 0.1 0.2 0.2
0.3 C16:1.sup..DELTA.9 0.3 0.2 0.2 0.2 3.0 3.1 2.4 1.2 1.1 0.7
C16:3.sup..DELTA.7, 12, 15 3.6 0.6 3.2 1.2 0.1 0.1 0.1 0.3 0.3 0.2
C18:0 2.4 3.3 2.7 3.9 3.2 2.8 2.8 4.6 4.5 4.1 C18:1.sup..DELTA.9
1.3 0.8 2.3 0.7 17.6 21.2 21.7 16.4 11.1 10.7 C18:1.sup..DELTA.11
0.1 0.1 0.1 0.1 2.1 1.8 1.5 0.9 0.8 0.7 C18:2.sup..DELTA.9, 12 23.7
17.5 24.3 15.2 28.2 22.0 17.0 36.5 32.6 24.6 C18:3.sup..DELTA.9,
12, 15 59.3 60.9 56.4 62.2 11.3 12.8 13.2 9.5 11.9 14.8 C20:0 0.3
0.4 0.3 0.5 1.4 1.2 1.3 2.1 2.1 2.1 C20:1.sup..DELTA.11 0.1 0.1 0.1
0.0 0.1 0.1 0.1 0.3 0.2 0.1 C20:2.sup..DELTA.11, 14 0.2 0.2 0.2 0.1
0.1 0.0 0.0 0.1 0.1 0.0 C20:3.sup..DELTA.11, 14, 17 0.1 0.2 0.1 0.1
0.0 0.0 0.0 0.0 0.0 0.0 C22:0 0.0 0.1 0.1 0.1 0.8 0.7 0.9 1.2 1.2
1.5 C24:0 0.3 0.2 0.2 0.2 0.7 0.5 0.7 0.9 0.8 1.4 .sup.a Leaf
samples were taken from wild type at flowering stage and from the
three pJP3503 primary transformants during seed setting. .sup.b
leaf stages by colour indicated by `G`, green; `YG`, yellow-green;
`Y`, yellow .sup.c very old leaf
TABLE-US-00036 TABLE 35 Total lipid yield (% weight of leaf dry
weight) and fatty acid composition of total lipid isolated from
differently aged leaves of wild-type and three selected tobacco
plants transformed with pJP3503. Plant: Wild type Plant 21 Plant 4
Plant 29 Leaf stage .sup.a G .sup.b G .sup.c YG G YG G YG Y G YG Y
%/leaf DW 2.4 1.8 1.4 2.3 2.1 11.6 15.8 13.0 10.1 8.8 3.7 C14:0 0.1
0.2 0.1 0.2 0.1 0.2 0.1 0.1 0.1 0.1 0.2 C16:0 11.6 11.9 16.0 11.9
13.7 26.6 30.0 34.6 21.0 28.0 29.4 C16:1.sup..DELTA.3t 4.1 6.3 3.2
3.1 2.0 0.5 0.4 0.5 0.8 0.6 0.9 C16:1.sup..DELTA.9 0.0 0.0 0.0 0.0
0.0 3.0 2.9 2.3 1.2 1.1 0.7 C16:3.sup..DELTA.7, 12, 15 6.7 5.3 3.6
5.6 5.3 0.4 0.3 0.3 1.0 0.9 1.5 C18:0 2.4 2.9 4.1 3.0 3.2 2.9 2.6
2.8 3.7 4.0 3.7 C18:1.sup..DELTA.9 1.4 1.2 0.9 1.4 0.5 15.8 20.2
20.8 13.6 10.2 11.3 C18:1.sup..DELTA.11 0.5 0.9 0.4 0.4 0.2 2.1 1.9
1.5 0.9 0.7 0.7 C18:2.sup..DELTA.9, 12 16.0 15.5 16.5 15.6 12.4
28.9 233 18.6 34.6 33.4 26.8 C18:3.sup..DELTA.9, 12, 15 54.4. 51.4
52.3 57.0 60.9 16.7 15.8 15.3 19.1 17.1 20.3 C20:0 0.5 0.6 0.8 0.4
0.5 1.2 1.0 1.3 1.6 1.7 1.6 C20:1.sup..DELTA.11 0.1 0.0 0.0 0.0 0.0
0.1 0.1 0.1 0.2 0.2 0.1 C20:2.sup..DELTA.11, 14 0.1 0.1 0.1 0.1 0.1
0.0 0.0 0.0 0.1 0.1 0.0 C20:3.sup..DELTA.11, 14, 17 0.1 0.1 0.1 0.1
0.1 0.0 0.0 0.0 0.0 0.0 0.0 C22:0 0.3 0.4 0.5 0.2 0.3 0.7 0.7 0.9
0.9 1.1 1.3 C24:0 0.3 0.3 0.4 0.2 0.3 0.6 0.5 0.7 0.7 0.8 1.2
.sup.a samples taken from plants harbouring multiple seed pods
unless indicated otherwise, .sup.b before flowering, .sup.c during
flowering
Analysis of Tobacco Plants Transformed with pJP3502
[1528] For the transformation with pJP3502 ("3 gene construct"),
the sucrose level in the MS agar medium was reduced to half the
standard level until sufficient calli were established, which aided
the recovery of transformants expressing WRI1. Forty-one primary
transformants were obtained from the transformation with pJP3502
and transferred to the greenhouse. Leaf samples of different age
were collected at either flowering or seed setting stages (Table
36). The plants look phenotypically normal except for three
transformants, originating from the same callus in the
transformation procedure and therefore likely to be from the same
transformation event, which were slightly smaller and displayed a
glossy leaf phenotype similar to that observed for plant 4 with
pJP3503 (above) but less in extent.
[1529] Leaf disk samples of primary transformants were harvested
during flowering and TAG was quantified visualized by iodine
staining after TLC. Selected transgenic plants displaying increased
TAG levels compared to the wild type controls were further analyzed
in more detail by TLC and GC. The highest TAG level in young green
leaves was detected in line 8.1 and corresponded to 8.3% TAG on a
dry weight basis or an approximate 83-fold increase compared to
wild type leaves of the same age (Table 36). Yellow-green leaves
typically contained a higher oil content compared to younger green
leaves with maximum TAG levels observed in line 14.1 (17.3% TAG on
a dry weight basis). Total lipid content and fatty acid composition
of total lipid in the leaves was also quantitated (Table 37).
[1530] Seed (T1 seed) was collected from the primary transformants
at seed maturity and some were sown to produce T1 plants. These
plants were predicted to be segregating for the transgene and
therefore some null segregants were expected in the T1 populations,
which could serve as appropriate negative controls in addition to
known wild-type plants which were grown at the same time and under
the same conditions. 51 T1 plants, derived from primary
transformant 14.1 which had a single-copy T-DNA insertion, which
were 6-8 weeks of age and 10-25 cm in height were analysed together
with 12 wild-type plants. The plants appeared phenotypically
normal, green and healthy, and did not appear smaller than the
corresponding wild-type plants. Leaf samples of about 1 cm diameter
were taken from fully expanded green leaves. 30 of the T1 plants
showed elevated TAG levels in the leaves, of which 8 plants showed
high levels of TAG, about double the level of TAG compared to the
primary transformant 14.1 at the same stage of plant development.
These latter plants are likely to be homozygous for the transgenes.
The level of TAG and the TAG fatty acid composition in leaves of
selected T1 plants were measured by loading lipid isolated from
about 5 mg dry weight of leaf tissue onto each TLC lane, the data
is shown in Table 38.
TABLE-US-00037 TABLE 36 TAG levels (% weight of leaf dry weight)
and fatty acid composition of TAG isolated from green leaves from
ten selected tobacco plants transformed with pJP3502. Line 2.1a 8.1
8.1 10.1 10.1 10.2 10.2 13.4 14.1 14.1 14.2 14.2 14.3 14.3 19.1
19.1 19.2 19.2 Stageb Y F Y F Y S Y F S Y S Y F Y F Y F Y TAG (%
dry weight) 2.5 8.3 7.2 6.2 11.8 6.4 7.6 5.7 4.6 17.3 2.5 12.6 3 2
5.1 5.5 4.3 3.2 C14:0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.1 0.2
0.1 0.1 0.2 0.1 0.1 0.2 0.1 C16:0 26.4 28.5 31.4 22.6 24.0 26.9
29.7 28 28.2 28.6 20.1 27.3 19.4 30.4 23.2 34.5 25.4 36.7 C16:1
.DELTA.3 0.4 0.3 0.4 0.3 0.3 0.3 0.4 0.3 0.3 0.4 0.5 0.3 0.2 0.0
0.3 0.4 0.3 0.2 C16:1 .DELTA.9 0.6 1.8 1.0 1.4 1.1 1.4 1.0 2 1.7
1.6 1.1 1.3 2.2 2.9 1.4 0.9 1.3 0.8 C16:3 .DELTA.7, 12, 15 0.3 0.4
0.4 0.3 0.4 0.3 0.4 0.2 0.3 0.2 0.5 0.3 0.3 0.1 0.2 0.3 0.4 0.3
C18:0 7.1 3.8 4.0 3.8 3.5 4 4.0 4.2 4.1 4.1 4.5 3.9 3.3 3.0 4 4.2
4.3 4.3 C18:1 .DELTA.9 9.6 18.1 11.2 33.1 25.1 21.3 10.4 24.8 18.6
25.8 16.1 17.3 14 1.9 25.5 8.5 20.2 10.4 C18:1 .DELTA.11 0.5 1.2
0.8 1.3 0.8 1 0.7 1.2 1.1 1.0 0.8 0.8 1 0.7 1.3 0.6 1.4 0.7 C18:2
.DELTA.9, 12 31.3 30.5 32.0 28 31.3 32.3 37.3 25.8 30.7 24.3 37.3
33.8 35.5 15.3 33.5 30.1 33.5 20.8 C18:3 .DELTA.9, 12, 15 17.9 10.8
13.2 5.9 10.2 8.1 10.2 8.8 9.4 9.8 14.6 10.2 21.5 44.0 6.5 15.7 8.5
21.1 C20:0 3 2 2.3 1.5 1.6 2 2.5 2 2.4 2.0 2.1 2.2 1.2 0.9 1.7 2.2
2 2.0 C20:1 .DELTA.11 0.3 0.3 0.3 0.3 0.0 0.3 0.3 0.3 0.4 0.0 0.5
0.0 0.3 0.0 0.4 0.0 0.4 0.2 C20:2 .DELTA.11, 14 0.1 0.1 0.1 o 0.1
0.1 0.1 o 0.1 0.1 o 0.1 0.1 0.0 0.1 0.0 0.1 0.0 C20:3 .DELTA.11,
14, 17 0 0 0.0 0 0.0 0 0.0 0 0 0.0 0 0.0 0 0.0 0 0.0 0 0.0 C22:0
1.6 1.2 1.7 0.8 1.0 1.2 1.8 1.1 1.5 1.1 1 1.4 0.5 0.3 0.9 1.4 1.1
1.2 C24:0 0.9 0.9 1.1 0.6 0.7 0.8 1.2 0.9 1.1 1.0 0.8 1.1 0.4 0.3
0.7 1.1 0.9 1.1 a very old plant containing only yellow leaves b
seed setting (`S`), flowering (`F`), yellow or yellowing leaves
(`Y`)
TABLE-US-00038 TABLE 37 Total lipid and fatty acid composition of
total lipid extracted from yellow leaves from selected tobacco
plants transformed with pJP3502 (DGAT1 + WRI1 + Oleosin) Line C14:0
C16:0 C16:d3 16:1w13t C16:1 C16:3 C18:0 C18:1 C18:1d11 14.1 0.1
26.6 0.0 0.6 1.6 0.3 3.8 25.6 1.1 14.2 0.1 25.2 0.0 0.6 1.3 0.4 3.6
16.5 0.8 10.1 0.1 22.4 0.0 0.7 1.3 0.6 3.2 24.3 0.8 13.4 0.2 19.6
0.0 3.6 0.0 1.7 4.1 3.9 0.6 mg/ C18:3n3 100 Line C18:2 DW C20:0
C20:1d11 C20:2n6 C20:3n3 C22:0 C24:0 mg 14.1 25.2 11.0 1.8 0.3 0.1
0.0 1.0 0.9 23.4 14.2 35.1 11.6 1.9 0.3 0.1 0.0 1.5 1.0 15.5 10.1
31.9 11.4 1.5 0.3 0.0 0.0 0.9 0.6 9.7 13.4 34.6 27.7 1.6 0.3 0.0
0.0 1.5 0.8 2.0
TABLE-US-00039 TABLE 38 TAG levels (% weight of leaf dry weight)
and fatty acid composition of TAG isolated from green leaves from
selected tobacco T1 plants transformed with pJP3502. Line No. 16:0
16:1 18:0 18:1d9 18:1d11 18:2 18:3n3 20:0 22:0 24:0 % TAG 4.1 23.3
0.9 3.3 11.3 1.5 44.8 10.7 1.9 1.4 0.9 3.7 4.2 22.4 0.9 3.1 13.3
1.5 44.3 10.5 1.8 1.3 0.9 6.1 4.3 24.2 1.0 3.4 14.9 1.6 41.8 9.0
1.9 1.3 0.9 4.0 6.1 24.6 0.9 3.9 16.5 1.4 33.4 14.4 2.1 1.5 1.3 3.5
6.2 22.8 0.8 3.8 18.6 1.4 32.7 15.1 2.1 1.5 1.1 3.4 6.3 26.6 1.0
4.2 16.2 1.5 31.0 15.6 2.3 1.6 0.0 2.3 8.1 27.0 1.0 4.8 18.3 1.5
27.1 15.9 2.6 1.9 0.0 1.5 8.2 24.2 1.0 4.3 19.0 1.4 27.6 16.7 2.5
1.8 1.5 2.2 8.3 26.5 1.3 4.8 22.0 1.7 24.9 16.2 2.6 0.0 0.0 1.2
13.1 33.7 1.3 5.0 7.4 1.3 34.2 14.2 2.8 0.0 0.0 1.2 13.2 29.1 1.1
4.4 7.2 1.3 37.2 17.1 2.6 0.0 0.0 1.6 13.3 34.3 0.0 5.5 6.9 0.0
36.4 13.7 3.2 0.0 0.0 0.8 21.1 27.4 0.7 4.2 8.5 1.2 37.1 15.4 2.4
1.6 1.4 2.1 21.2 29.7 0.9 4.5 9.1 1.3 36.3 15.9 2.3 0.0 0.0 1.6
21.3 27.1 0.8 4.3 12.7 1.4 37.1 13.0 2.2 1.4 0.0 2.4 29.1 27.2 0.8
4.3 12.8 1.1 34.9 14.4 2.1 1.4 1.0 3.9 29.2 26.9 1.0 4.1 14.7 1.2
35.3 13.0 2.0 1.2 0.8 3.8 29.3 25.7 1.4 4.1 18.4 1.2 35.7 11.0 1.6
1.0 0.0 3.7 23.1 29.9 0.9 4.3 8.1 1.2 35.0 18.4 2.1 0.0 0.0 1.6
23.2 30.8 1.0 4.8 9.3 1.3 33.5 17.2 2.3 0.0 0.0 1.5 23.3 29.2 0.9
4.3 9.1 1.3 36.2 15.2 2.3 1.5 0.0 2.3 49.1 27.0 0.9 3.9 5.8 1.4
43.8 11.0 2.5 2.1 1.5 2.4 49.2 27.5 0.9 3.8 7.1 1.5 44.7 10.2 2.4
2.0 0.0 2.2
[1531] Genetic constructs suitable for transformation of
monocotyledonous plants are made by exchanging the Arath-SSU
promoters in pJP3502 and pJP3503 for promoters more active in
monocots. Suitable promoters include constitutive viral promoters
from monocot viruses or promoters that have demonstrated to
function in a transgenic context in monocot species (e.g., the
maize Ubi promoter described by Christensen et al., 1996).
Similarly, the CaMV-35S promoters in pJP3502 and pJP3503 are
exchanged for promoters that are more active in monocot species.
These constructs are transformed into wheat, barley and maize using
standard methods.
Miscanthus Species
[1532] Genetic constructs for Miscanthus species transformation are
made by exchanging the Arath-SSU promoters in pJP3502 and pJP3503
for promoters more active in Miscanthus. Suitable promoters include
constitutive viral promoters, a ubiquitin promoter (Christensen et
al., 1996) or promoters that have demonstrated to function in a
transgenic context in Miscanthus. Similarly, the CaMV-35S promoters
in pJP3502 and pJP3503 are exchanged for promoters that are more
active in Miscanthus. New constructs are transformed in Miscanthus
by a microprojectile-mediated method similar to that described by
Wang et al., 2011.
Switchgrass (Panicum virgatum)
[1533] Genetic constructs for switchgrass transformation are made
by exchanging the Arath-SSU promoters in pJP3502 and pJP3503 for
promoters more active in switchgrass. Suitable promoters include
constitutive viral promoters or promoters that have demonstrated to
function in a transgenic context in switchgrass (e.g., Mann et al.,
2011). Similarly, the CaMV-35S promoters in pJP3502 and pJP3503 are
exchanged for promoters that are more active in switchgrass. New
constructs are transformed in switchgrass by an
Agrobacterium-mediated method similar to that described by Chen et
al., 2010 and Ramamoorthy and Kumar, 2012.
Sugarcane
[1534] Genetic constructs for sugarcane transformation are made by
exchanging the Arath-SSU promoters in pJP3502 and pJP3503 for
promoters more active in sugarcane. Suitable promoters include
constitutive viral promoters or promoters that have demonstrated to
function in a transgenic context in sugarcane (e.g., the maize Ubi
promoter described by Christensen et al., 1996). Similarly, the
CaMV-35S promoters in pJP3502 and pJP3503 are exchanged for
promoters that are more active in sugarcane. New constructs are
transformed in sugarcane by a microprojectile-mediated method
similar to that described by Bower et al., 1996.
Elephant Grass
[1535] Genetic constructs for Pennisetum purpureum transformation
are made by exchanging the Arath-SSU promoters in pJP3502 and
pJP3503 for promoters more active in elephant grass. Suitable
promoters include constitutive viral promoters or promoters that
have demonstrated to function in a transgenic context in Pennisetum
species such as P. glaucum like (e.g. the maize Ubi promoter
described by Christensen et al., 1996). Similarly, the CaMV-35S
promoters in pJP3502 and pJP3503 are exchanged for promoters that
are more active in Pennisetum species. New constructs are
transformed in P. purpureum by a microprojectile-mediated method
similar to that described by Girgi et al., 2002.
Lolium
[1536] Genetic constructs for Lolium perenne and other Lolium
species transformation are made by exchanging the Arath-SSU
promoters in pJP3502 and pJP3503 for promoters more active in
ryegrass. Suitable promoters include constitutive viral promoters
or promoters that have demonstrated to function in a transgenic
context in Lolium species (e.g. the maize Ubi promoter described by
Christensen et al., 1996). Similarly, the CaMV-35S promoters in
pJP3502 and pJP3503 are exchanged for promoters that are more
active in Pennisetum species. New constructs are transformed in
Lolium perenne by a silicon carbide-mediated method similar to that
described by Dalton et al., 2002 or an Agrobacterium-mediated
method similar to that described by Bettany et al., 2003.
[1537] pJP3502 and pJP3503 are modified to seed-specific expression
genetic constructs by exchanging the CaMV-35S and Arath-SSU
promoters (except the selectable marker cassette) with
seed-specific promoters active in the target species.
Canola
[1538] Genetic constructs for Brassica napus transformation are
made by exchanging the CaMV-35S and Arath-SSU promoters in pJP3502
and pJP3503 for promoters more active in canola. Suitable promoters
include promoters that have previously been demonstrated to
function in a transgenic context in Brassica napus (e.g., the A.
thaliana FAE1 promoter, Brassica napus napin promoter, Linum
usitatissimum conlinin1 and conlinin2 promoters). New constructs
are transformed in B. napus as previously described.
Soybean (Glycine max)
[1539] A genetic construct is made by cloning the PspOMI fragment
from a synthesised DNA fragment having the nucleotide sequence
shown in SEQ ID NO:415 (Soybean synergy insert; FIG. 19A) into a
binary vector such as pORE04 at the NotI site. This fragment
contains Arath-WRI1 expressed by a Arath-FAE1 promoter, Arath-DGAT1
expressed by a Linus-Cnl2 promoter, Musmu-MGAT2 expressed by
Linus-Cnl1 and Arath-GPAT4 expressed by Linus-Cnl1. A further
genetic construct is made by exchanging the GPAT coding region for
an oleosin coding region. A further genetic construct is made by
deleting the MGAT expression cassette.
[1540] A genetic construct, pJP3569 (FIG. 21), was generated by
cloning the SbfI-PstI fragment from the DNA molecule having the
nucleotide sequence shown in SEQ ID NO:415 into the PstI site of
pORE04. This construct contained (i) a coding region encoding the
A. thaliana WRI1 transcription factor, codon optimised for G. max
expression, and expressed from the G. max kunitz trypsin inhibitor
3 (Glyma-KTi3) promoter, (ii) a coding region encoding the
Umbelopsis ramanniana DGAT2A (codon optimised as described by
Lardizabal et al., 2008) and expressed from the G. mar
alpha-subunit beta-conglycinin (Glyma-b-conglycinin) promoter and
(iii) a coding region encoding the M. musculus MGAT2, codon
optimised for G. mar expression. A second genetic construct,
pJP3570, was generated by cloning the SbfI-SwaI fragment of the DNA
molecule having the nucleotide sequence shown in SEQ ID NO:415 into
pORE04 at the EcoRV-PstI sites to yield a binary vector containing
genes expressing the A. thaliana WRI1 transcription factor and U.
ramanniana DGAT2A enzyme. Similarly, a third genetic construct,
pJP3571, was generated by cloning the AsSI fragment of the DNA
molecule having the nucleotide sequence shown in SEQ ID NO:415 into
the AsiSI site of pORE04 to yield a binary vector containing a gene
encoding the U. ramanniana DGAT2A enzyme. A fourth genetic
construct, pJP3572, was generated by cloning the NotI fragment of
the DNA molecule having the nucleotide sequence shown in SEQ ID
NO:415 into pORE04 at the NotI site to yield a binary vector
containing a gene expressing the A. thaliana WRI1 transcription
factor. A fifth genetic construct, pJP3573, was generated by
cloning the SwaI fragment of the DNA molecule having the nucleotide
sequence shown in SEQ ID NO:415 into pORE04 at the EcoRV site to
yield a binary vector containing the gene encoding M. musculus
MGAT2.
[1541] A sixth genetic construct, pJP3580, is generated by
replacing the M. musculus MGAT2 with the Sesamum indicum oleosin
gene.
[1542] Each of these six constructs are used to transform soybean,
using the methods as described in Example 6. Transgenic plants
produced by the transformation with each of the constructs,
particularly pJP3569, produce seeds with increased oil content.
Sugarbeet
[1543] The vectors pJP3502 and pJP3503 (see above) as used for the
transformation of tobacco are used to transform plants of sugarbeet
(Beta vulgaris) by Agrobacterium-mediated transformation as
described by Lindsey & Gallois (1990). The plants produce
greatly increased levels of TAG in their leaves, similar in extent
to the tobacco plants produced as described above. Transgenic
sugarbeet plants are harvested while the leaves are still green or
preferably green/yellow just prior to beginning of senescence or
early in that developmental process, i.e., and while the sugar
content of the beets is at a high level and after allowing
accumulation of TAG in the leaves. This allows the production of
dual-purpose sugarbeets which are suitable for production of both
sugar from the beets and lipid from the leaves; the lipid may be
converted directly to biodiesel fuel by crushing the leaves and
centrifugation of the resultant material to separate the oil
fraction, or the direct production of hydrocarbons by pyrolosis of
the leaf material.
[1544] Promoters that are active in the root (tuber) of sugarbeet
are also used to express transgenes in the tuber.
Example 21. Stable Transformation of Solanum tuberosum with Oil
Increase Genes
[1545] pJP3502, the intermediate binary expression vector described
in the previous example, was modified by first excising one SSU
promoter by AscI+NcoI digestion and replacing it with the potato
B33 promoter flanked by AscI and NcoI to generate pJP3504. The SSU
promoter in pJP3504 along with a fragment of the A. thaliana WRL1
gene was replaced at the PspOMI sites by a potato B33 promoter with
the same A. thaliana WRL1 gene fragment flanked by NotI-PspOMI to
generate pJP3506. The pJP3347 was added to pJP3506 as described in
the above example to generate pJP3507. This construct is shown
schematically in FIG. 20. Its sequence is given in SEQ ID NO:413.
The construct is used to transform potato (Solanum tuberosum) to
increase oil content in tubers.
Example 22. GPAT-MGAT Fusion Enzymes
[1546] The enzyme activity of GPAT-MGAT enzyme fusions is tested to
determine whether this would increase the accessibility of the
GPAT-produced MAG for MGAT activity. A suitable linker region was
first synthesised and cloned into a cloning vector. This linker
contained suitable sites for cloning the N-terminal (EcoRI-ZraI)
and C-terminal coding regions (NdeI-SmaI or NdeI-PstI).
TABLE-US-00040 (SEQ ID NO: 414)
atttaaatgcggccgcgaattcgtcgattgaggacgtccctactagacct
gctggacctcctcctgctacttactacgattctctcgctgtgcatatggt
cagtcatgccegggcctgcaggcggccgcatttaaat
[1547] A GPAT4-MGAT2 fusion (GPAT4 N-terminus and MGAT2 C-terminus)
was made by first cloning a DNA fragment encoding the A. thaliana
GPAT4, flanked by MfeI and ZraI sites and without a C-terminal stop
codon, into the EcoRI-ZraI sites. The DNA fragment encoding the M.
musculus MGAT2, flanked by NdeI-PstI sites, was then cloned into
the NdeI-PstI sites to generate a single GPAT4-MGAT2 coding
sequence. The fused coding sequence was then cloned as a NotI
fragment into pYES2 to generate pYES2::GPAT4-MGAT2 and the
constitutive binary expression vector pJP3343 to generate
pJP3343::GPAT4-MGAT2.
[1548] Similarly, a MGAT2-GPAT4 fusion (MGAT2 N-terminus and GPAT4
C-terminus) was made by first cloning the DNA fragment encoding M.
musculus MGAT2, flanked by EcoRI and ZraI sites without a
C-terminal stop codon, into the EcoRI-ZraI sites. The DNA fragment
encoding the A. thaliana GPAT4, flanked by NdeI-PstI sites, was
then cloned into the NdeI-PstI sites to generate a single
MGAT2-GPAT4 coding sequence. The fused coding sequence was then
cloned as a NotI fragment into pYES2 to generate pYES2::MGAT2-GPAT4
and the constitutive binary expression vector pJP3343 to generate
pJP3343::MGAT2-GPAT4.
[1549] The yeast expression vectors are tested in yeast S.
cerevisiae and the binary vectors are tested in N. benthamiana and
compared for oil content and composition with single-coding region
controls.
Example 23. Discovery of Novel WRL1 Sequences
[1550] Three novel WRL1 sequences are cloned into pJP3343 and other
suitable binary constitutive expression vectors and tested in N.
benthamiana. These include the genes encoding Sorbi-WRL1 (from
Sorghum bicolor; SEQ ID NO:334), Lupan-WRL1 (from Lupinus
angustifolius; SEQ ID NO:335) and Ricco-WRL1 (from Ricinus
communis; SEQ ID NO:336). These constructs are tested in comparison
with the Arabidopsis WRI1-encoding gene in the N. benthamiana leaf
assay.
[1551] As an initial step in the procedure, a partial cDNA fragment
corresponding to the WRL1 was identified in the developing seed EST
database of Lupinus angustifolius (NA-080818_Plate14f06.b1, SEQ ID
NO:277). A full-length cDNA (SEQ ID NO:278) was subsequently
recovered by performing 5'- and 3'-RACE PCR using nested primers
and cDNAs isolated from developing seeds of Lupinus angustifolius.
The full length cDNA was 1729 bp long, including a 1284 bp protein
coding sequence encoding a predicted polypeptide of 428 amino acids
(SEQ ID NO:337). The entire coding region of the full length lupin
WRL1 cDNA was then PCR amplified using forward and reverse primers
which both incorporated EcoRI restriction sites to facilitate the
cloning into the pJP3343 vector under the control of a 35S promoter
in the sense orientation. A. tumefaciens strain AGL1 harbouring the
pJP3343-LuangWRL1 was infiltrated in N. benthamiana leave tissues
as described in Example 1. Leaf discs transiently expressing the
pJP3343-LuangWRL1 were then harvested and analysed for oil
content.
Example 24. Silencing of the CGI-58 Homologue N. tabacum
[1552] James et al. (2010) have reported that the silencing of the
A. thaliana CGI-58 homologue resulted in up to 10-fold TAG
accumulation in leaves, mainly as lipid droplets in the cytosol.
Galactolipid levels were also found to be higher, whereas levels of
most major phospholipid species remained unchanged. Interestingly,
TAG levels in seeds were unaffected and, unlike other TAG
degradation mutants, no negative effect on seed germination was
observed.
[1553] Three full length and two partial transcripts were found in
the N. benthamiana transcriptome showing homology to the A.
thaliana CGI-58 gene. A 434 bp region present in all five
transcripts was amplified from N. benthamiana isolated leaf RNA and
cloned via LR cloning (Gateway) into the pHELLSGATE12 destination
vector. The resulting expression vector designated pTV46 encodes a
hairpin RNA (dsRNA) molecule for reducing expression of the tobacco
gene encoding the homologue of CG1-58 and was used to transform N.
tabacum as described in Example 1, yielding 52 primary
transformants.
[1554] Primary transformants displaying increased TAG levels in
their vegetative tissues are crossed with homozygous lines
described in Example 20.
Example 25. Silencing of the N. Tabacum ADP-Glucose
Pyrophosphorylase (AGPase) Small Subunit
[1555] Sanjaya et al. (2011) demonstrated that silencing of the
AGPase small subunit in combination with WRI over-expression
further increases TAG accumulation in A. thaliana seedlings while
starch levels were reduced. An AGPase small subunit has been cloned
from flower buds (Kwak et al., 2007). The deduced amino acid
sequence showed 87% identity with the A. thaliana AGPase. A 593 bp
fragment was synthesized and cloned into pHELLSGATE12 via LR
cloning (Gateway) resulting in the binary vector pTV35.
Transformation of N. tabacum was done as described in Example 1 and
yielded 43 primary transformants.
[1556] Primary transformants displaying a reduction in total leaf
starch levels are crossed with homozygous lines described in
Examples 20 and 21. In addition, primary transformants are crossed
with homozygous lines that are the result of a crossing of the
lines described in 20 and 21.
Example 26. Production and Use of Constructs for Gene Combinations
Including an Inducible Promoter
[1557] Further genetic constructs are made using an inducible
promoter system to drive expression of at least one of the genes in
the combinations of genes as described above, particularly in
pJP3503 and pJP3502. In the modified constructs, the WRI1 gene is
expressed by an inducible promoter such as the Aspergillus niger
alcA promoter in the presence of an expressed Aspergillus niger
alcR gene. Alternatively, a DGAT is expressed using an inducible
promoter. This is advantageous when maximal TAG accumulation is not
desirable at all times during development. An inducible promoter
system or a developmentally-controlled promoter system, preferably
to drive the transcription factor such as WRI1, allows the
induction of the high TAG phenotype at an appropriate time during
development, and the subsequent accumulation of TAG to high
levels.
[1558] TAG can be further increased by the co-expression of
transcription factors including embryogenic transcription factors
such as LEC2 or BABY BOOM (BBM, Srinivasan et al., 2007). These are
expressed under control of inducible promoters are described above
and super-transformed on transgenic lines or co-transformed with
WRI and DGAT.
[1559] pJP3590 is generated by cloning a MAR spacer as a AalI
fragment into the AaiII site of pORE04. pJP3591 is generated by
cloning a second MAR spacer as an KpnI fragment into the KpnI site
of pJP3590. pJP3592 is generated by cloning the AsiSI-SmaI fragment
of the DNA molecule having the nucleotide sequence shown in SEQ ID
NO:416 (12ABFJYC_pJP3569_insert; FIG. 19B) into the AsiSI-EcoRV
sites of pJP3591. pJP3596 is generated by cloning a PstI-flanked
inducible expression cassette containing the alcA promoter
expressing the M. musculus MGAT2 and a Glycine max lectin
polyadenylation signal into an introduced SbfI site in pJP3592.
Hygromycin-resistant versions of both pJP3592 and pJP3596 (pJP3598
and pJP3597, respectively) are generated by replacing the NPTII
selectable marker gene with the HPH flanked gene at the FseI-AscI
sites.
[1560] These constructs are used to transform the same plant
species as described in Example 20. Expression from the inducible
promoter is increased by treatment with the inducer of the
transgenic plants after they have grown substantially, so that they
accumulate increased levels of TAG. These constructs are also
super-transformed in stably transformed constructs already
containing an oil-increase construct including the three-gene or
four-gene TDNA region (SEQ ID NO:411 and SEQ ID NO:412,
respectively). Alternatively, the gene expression cassettes from
the three-gene and four-gene constructs are cloned into the NotI
sites of pJP3597 and pJP3598 to yield a combined constitutive and
inducible vector system for high fatty acid and TAG synthesis,
accumulation and storage.
[1561] In addition to other inducible promoters, an alternative is
that gene expression can be temporally and spatially restricted by
using promoters that are only active during specific developmental
periods or in specific tissues. Endogenous chemically inducible
promoters are also used to limit expression to specific
developmental windows.
[1562] It will be appreciated by persons skilled in the art that
numerous variations and/or modifications may be made to the
invention as shown in the specific embodiments without departing
from the spirit or scope of the invention as broadly described. The
present embodiments are, therefore, to be considered in all
respects as illustrative and not restrictive.
[1563] The present application claims priority from U.S. 61/580,590
filed 27 Dec. 2011 and U.S. 61/718,563 filed 25 Oct. 2012, the
entire contents of both of which are incorporated herein by
reference.
[1564] All publications discussed and/or referenced herein are
incorporated herein in their entirety.
[1565] Any discussion of documents, acts, materials, devices,
articles or the like which has been included in the present
specification is solely for the purpose of providing a context for
the present invention. It is not to be taken as an admission that
any or all of these matters form part of the prior art base or were
common general knowledge in the field relevant to the present
invention as it existed before the priority date of each claim of
this application.
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Sequence CWU 0 SQTB SEQUENCE LISTING The patent application
contains a lengthy "Sequence Listing" section. A copy of the
"Sequence Listing" is available in electronic form from the USPTO
web site
(http://seqdata.uspto.gov/?pageRequest=docDetail&DocID=US20190203125A1).
An electronic copy of the "Sequence Listing" will also be available
from the USPTO upon request and payment of the fee set forth in 37
CFR 1.19(b)(3).
0 SQTB SEQUENCE LISTING The patent application contains a lengthy
"Sequence Listing" section. A copy of the "Sequence Listing" is
available in electronic form from the USPTO web site
(http://seqdata.uspto.gov/?pageRequest=docDetail&DocID=US20190203125A1).
An electronic copy of the "Sequence Listing" will also be available
from the USPTO upon request and payment of the fee set forth in 37
CFR 1.19(b)(3).
* * * * *
References