Delta-5 desaturase and its use in making polyunsaturated fatty acids

1. A polynucleotide operably linked to a heterologous nucleic acid sequence comprising:

(a) a nucleotide sequence encoding a polypeptide having delta-5 desaturase activity, wherein the polypeptide has an amino acid sequence of at least 90% amino acid identity, based on the Clustal W method of alignment provided by the MegAlign™ v6.1 program of the DNASTAR LASERGENE bioinformatics computing suite (default parameters: GAP PENALTY=20, GAP LENGTH PENALTY=0.2, Delay Divergen Seqs(%)=30, DNA Transition Weight=0.5, Protein Weight Matrix=Gonnet Series, DNA Weight Matrix=IUB), when compared to an amino acid sequence as set forth in SEQ ID NO:2;

(b) a nucleotide sequence encoding a polypeptide having delta-5 desaturase activity, wherein the nucleotide sequence has at least 90% sequence identity, based on the Basic Local Alignment Search Tool (“BLASTN”) method of alignment provide by the National Center for Biotechnology Information (default parameters: short queries=automatically adjust parameters for short input sequences, expect threshold=10, and filter=low complexity regions), when compared to a nucleotide sequence as set forth in SEQ ID NO:1 or SEQ ID NO:3; or

(c) a complement of the nucleotide sequence of (a) or (b), wherein the complement and the nucleotide sequence consist of the same number of nucleotides and are 100% complementary.

2. The polynucleotide of claim 1 wherein the nucleotide sequence comprises SEQ ID NO:1 or SEQ ID NO:3.

3. The polynucleotide of claim 1 , wherein the amino acid sequence of the polypeptide of step (a) comprises

(a) SEQ ID NO:2; or

(b) an amino acid sequence that differs from the amino acid sequences in (a) by at least one conservative amino acid substitution.

4. A recombinant DNA construct comprising the polynucleotide of claim 1 , 2 , or 3 operably linked to at least one regulatory sequence.

5. A cell comprising in its genome the recombinant DNA construct of claim 4 .

6. The cell of claim 5 wherein said cell is selected from the group consisting of plants and yeast.

7. A method for transforming a cell, comprising transforming a cell with the recombinant DNA construct of claim 4 and selecting those cell transformed with the recombinant DNA construct.

8. A method for producing a transformed plant comprising transforming a plant cell with the recombinant DNA construct of claim 4 and regenerating a plant from the transformed plant cell, wherein the transformed plant comprises the recombinant DNA construct.

9. The method of claim 8 wherein the plant is a soybean plant.

10. A transgenic seed comprising in its genome the recombinant DNA construct of claim 4 .

11. A transgenic seed obtained from the transformed plant made by the method of claim 8 , wherein the transgenic seed comprises the recombinant DNA construct.

12. A method for making long-chain polyunsaturated fatty acids in a plant cell comprising:

(a) transforming a cell with the recombinant DNA construct of claim 4 ; and

(b) selecting those transformed cells that make long-chain polyunsaturated fatty acids.

13. An oilseed plant comprising in its genome the recombinant DNA construct of claim 4 .

14. The oilseed plant of claim 13 , wherein the oilseed plant is selected from the group consisting of soybean, Brassica species, sunflower, maize, cotton, flax and safflower.

15. A transgenic progeny plant obtained from the plant made by the method of claim 8 , wherein the progeny plant comprises the recombinant DNA construct.

16. A polynucleotide operably linked to a heterologous nucleic acid sequence which encodes a delta-5 desaturase as set forth in SEQ ID NO:2 wherein at least one codon is codon-optimized for expression in Yarrowia sp.

17. A method for producing an altered level of at least one polyunsaturated fatty acid in a seed of an oilseed plant comprising:

(a) transforming an oilseed plant cell with the recombinant DNA construct of claim 4 and at least one additional recombinant DNA construct comprising an isolated polynucleotide, operably linked to at least one regulatory sequence, encoding a polypeptide selected from the group consisting of a delta-4 desaturase, a delta-5 desaturase, a delta-6 desaturase, a delta-8 desaturase, a delta-12 desaturase, a delta-15 desaturase, a delta-17 desaturase, a delta-9 desaturase, a delta-9 elongase, a C14/16 elongase, a C16/18 elongase, a C18/20 elongase and a C20/22 elongase;

(b) regenerating a transgenic oilseed plant from the transformed cell of step (a); and

(c) selecting a transgenic seed obtained from the transgenic oilseed plant of step (b) having an altered level of at least one polyunsaturated fatty acids when compared to the level in a seed obtained from a nontransformed oilseed plant.

18. The method of claim 17 wherein the oilseed plant is selected from the group consisting of soybean, Brassica species, sunflower, maize, cotton, flax, and safflower.

19. An oilseed plant comprising:

(a) the recombinant DNA construct of claim 4 ; and

(b) at least one additional recombinant DNA construct comprising an isolated polynucleotide, operably linked to at least one regulatory sequence, encoding a polypeptide selected from the group consisting of a delta-4 desaturase, a delta-5 desaturase, a delta-6 desaturase, a delta-8 desaturase, a delta-12 desaturase, a delta-15 desaturase, a delta-17 desaturase, a delta-9 desaturase, a delta-9 elongase, a C14/16 elongase, a C16/18 elongase, a C18/20 elongase and a C20/22 elongase.

20. The oilseed plant of claim 19 , wherein the oilseed plant is selected from the group consisting of soybean, Brassica species, sunflower, maize, cotton, flax and safflower.

21. A transgenic seed obtained from the oilseed plant of claim 19 , wherein the transgenic seed comprises the recombinant DNA construct.

22. A transgenic seed obtained from the oilseed plant of claim 20 , wherein the transgenic seed comprises the recombinant DNA construct.