Compositions and methods for engineering oil content in plants

1. A transgenic plant transformed with

(i) a first expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to a nucleotide sequence encoding an Arabidopsis diacylglycerol actyltransferase 1 (DGAT1) protein,

(ii) a second expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to a plant or yeast glycerol 3-phosphate dehydrogenase 1 (GPD1) protein, and

(iii) a third expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to the nucleotide sequence set forth in SEQ ID NO: 3 encoding monoacylglycerol O-acyltransferase 1 (MGAT1) protein,

wherein overexpression of said DGAT1, GPD1, and MGAT1 proteins in said transgenic plant results in increased total seed oil content per transgenic plant and increased seed yield per transgenic plant as compared to a control plant of the same species lacking said first, second, and third expression cassettes and grown under identical growth conditions.

2. The transgenic plant of claim 1 , wherein said nucleotide sequence encoding said Arabidopsis diacylglycerol actyltransferase 1 (DGAT1) protein is SEQ ID NO: 1.

3. The transgenic plant of claim 1 , wherein said nucleotide sequence encoding said plant or yeast glycerol 3-phosphate dehydrogenase 1 (GPD1) protein is SEQ ID NO: 2.

4. The transgenic plant of claim 1 , wherein said transgenic plant is further transformed with a fourth expression cassette comprising

(i) a heterologous plant-expressible seed-specific promoter operably linked to a nucleotide sequence encoding a plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein, or

(ii) an RNA interference (RNAi) suppressor construct comprising a heterologous plant-expressible seed-specific promoter operably linked to a nucleic acid sequence encoding an RNAi suppressor of expression of endogenous plant Sugar Dependent 1 (SDP1) protein in said transgenic plant,

wherein overexpression of said PDCT1 protein or reduction in the expression of said endogenous plant SDP1 protein in said transgenic plant by said RNAi suppressor results in increased total transgenic seed oil content per transgenic plant and increased seed yield per transgenic plant as compared to a control plant of the same species lacking said fourth expression cassette and grown under identical growth conditions.

5. The transgenic plant of claim 4 , wherein said nucleotide sequence encoding said plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein is SEQ ID NO: 4; or

wherein said RNAi suppressor construct has the nucleotide sequence set forth in SEQ ID NO: 13.

6. The transgenic plant of claim 1 , wherein said total seed oil content per transgenic plant is increased by at least 15% as compared to said control plant.

7. The transgenic plant of claim 1 , wherein said seed yield, as measured in weight of seed, per transgenic plant is increased by at least 50% as compared to said control plant.

8. The transgenic plant of claim 1 , wherein said glycerol-3-phosphate dehydrogenase 1 (GPD1) protein is from a yeast genus selected from the group consisting of Cryptococcus, Torulopsis, Pityrosporum, Brettanomyces, Candida, Kloeckera, Trigonopsis, Trichosporon, Rhodotorula, Sporobolomyces, Bullera, Saccharomyces, Debaromyces, Lipomyces, Hansenula, Endomycopsis, Pichia and Hanseniaspora.

9. The transgenic plant of claim 4 , wherein the plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein is from a plant genus selected from the group consisting of Arabidopsis, Tropaeolum, Brassica, Glycine, Linum, Helianthus, Camelina, Arachis, Ricinus, Cuphea, Crambe and Gossipium.

10. The transgenic plant of claim 1 , wherein said transgenic plant is selected from the group consisting of Arabidopsis thaliana, Borago species, Canola species, Ricinus species, Theobroma species, Zea species, Gossypium species, Crambe species, Cuphea species, Linum species, Lesquerella species, Limnanthes species, Linola species, Tropaeolum species, Oenothera species, Olea species, Elaeis species, Arachis species, rapeseed species, Carthamus species, Glycine species, Soja species, Helianthus species, Nicotiana species, Vermonia species, Triticum species, Hordeum species, Oryza species, Avena species, Sorghum species and Secale species.

11. The transgenic plant of claim 1 , wherein said transgenic plant is selected from the group consisting of Borago officinalis, Brassica campestris, Brassica napus, Brassica rapa, Camelina species, Cannabis sativa, Carthamus tinctorius, Cocos nucifera, Crambe abyssinica, Cuphea species, Elaeis guinensis, Elaeis oleifera, Glycine max, Gossypium hirsutum, Gossypium barbadense, Gossypium herbaceum, Helianthus annuus, Linum usitatissimum, Oenothera biennis, Olea europaea, Oryza sativa, Ricinus communis, Sesamum indicum, Triticum species, Zea mays , walnut species and almond species.

12. A method of making a transgenic plant with increased total seed oil content and increased seed yield, said method comprising:

transforming plant cells with

(i) a first expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to a nucleotide sequence encoding an Arabidopsis diacylglycerol actyltransferase 1 (DGAT1) protein,

(ii) a second expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to a plant or yeast glycerol 3-phosphate dehydrogenase 1 (GPD1) protein, and

(iii) a third expression cassette comprising a heterologous plant-expressible seed-specific promoter operably linked to the nucleotide sequence as set forth in SEQ ID NO: 3 encoding the monoacylglycerol O-acyltransferase 1 (MGAT1) protein to produce transformed cells;

generating transformed plants from the transformed cells; and

selecting a transgenic plant from the transformed plants, wherein the selected transgenic plant overexpresses said DGAT1, GPD1 and MGAT1 proteins and exhibits increased total seed oil content per transgenic plant and increased seed yield per transgenic plant as compared to a control plant of the same species lacking said first, second, and third expression cassettes and grown under identical growth conditions.

13. The method of claim 12 , wherein said nucleotide sequence encoding said Arabidopsis diacylglycerol actyltransferase 1 (DGAT1) protein is SEQ ID NO: 1, or

wherein said nucleotide sequence encoding said plant or yeast glycerol 3-phosphate dehydrogenase 1 (GPD1) protein has the nucleotide sequence is SEQ ID NO: 2.

14. The method of claim 12 , wherein total seed oil content per transgenic plant is increased by at least 15% as compared to said control plant; and

wherein seed yield, as measured in weight of seed, per transgenic plant is increased by at least 50% as compared to said control plant.

15. The method of claim 12 , wherein said selected transgenic plant is further transformed with a fourth expression cassette comprising

(i) a nucleic acid molecule comprising a heterologous plant-expressible seed-specific promoter operably linked to a nucleotide sequence encoding a plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein, or

(ii) an RNA interference (RNAi) suppressor construct comprising a heterologous plant-expressible seed-specific promoter operably linked to a nucleic acid sequence encoding an RNAi suppressor of expression of endogenous plant Sugar Dependent 1 (SDP1) protein in said transgenic plant,

wherein overexpression of said PDCT1 protein or reduction in the expression of said endogenous plant SDP1 protein in said transgenic plant by said RNAi suppressor results in increased total seed oil content per transgenic plant and increased seed yield per transgenic plant as compared to a control plant of the same species lacking said fourth expression cassette and grown under identical growth conditions.

16. The method of claim 15 , wherein said nucleotide sequence encoding said plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein is SEQ ID NO: 4, or

wherein said RNAi suppressor construct has the nucleotide sequence set forth in SEQ ID NO: 13.

17. The method of claim 12 , wherein said glycerol-3-phosphate dehydrogenase 1 (GPD1) protein is from a yeast genus selected from the group consisting of Cryptococcus, Torulopsis, Pityrosporum, Brettanomyces, Candida, Kloeckera, Trigonopsis, Trichosporon, Rhodotorula, Sporobolomyces, Bullera, Saccharomyces, Debaromyces, Lipomyces, Hansenula, Endomycopsis, Pichia and Hanseniaspora.

18. The method of claim 15 , wherein the plant phosphatidylcholine diacylglycerol cholinephosphotransferase 1 (PDCT1) protein is from a plant genus selected from the group consisting of Arabidopsis, Tropaeolum, Brassica, Glycine, Linum, Helianthus, Camelina, Arachis, Ricinus, Cuphea, Crambe and Gossipium.

19. The method of claim 12 , wherein said transgenic plant is selected from the group consisting of Arabidopsis thaliana, Borago species, Canola species, Ricinus species, Theobroma species, Zea species, Gossypium species, Crambe species, Cuphea species, Linum species, Lesquerella species, Limnanthes species, Linola species, Tropaeolum species, Oenothera species, Olea species, Elaeis species, Arachis species, rapeseed species, Carthamus species, Glycine species, Soja species, Helianthus species, Nicotiana species, Vermonia species, Triticum species, Hordeum species, Oryza species, Avena species, Sorghum species and Secale species.

20. The method of claim 12 , wherein said transgenic plant is selected from the group consisting of Borago officinalis, Brassica campestris, Brassica napus, Brassica rapa, Camelina species, Cannabis sativa, Carthamus tinctorius, Cocos nucifera, Crambe abyssinica, Cuphea species, Elaeis guinensis, Elaeis oleifera, Glycine max, Gossypium hirsutum, Gossypium barbadense, Gossypium herbaceum, Helianthus annuus, Linum usitatissimum, Oenothera biennis, Olea europaea, Oryza sativa, Ricinus communis, Sesamum indicum, Triticum species, Zea mays , walnut species and almond species.