Methods and compositions for synthesis of long chain poly-unsaturated fatty acids in plants

A nucleic acid construct comprising one or more nucleotide sequences depicted in a SEQ ID NO:

• selected from the group consisting of SEQ ID NO:1 and SEQ ID NO:3 operably associated with an expression control sequence in a plant cell.

A nucleic acid construct comprising a nucleotide sequence which encodes a polypeptide comprising the amino acid sequence depicted in SEQ ID NO:2, wherein said nucleotide sequence is operably associated with a transcription or an expression control sequence functional in a plant cell, wherein said nucleotide sequence encodes a functionally active polypeptide which removes hydrogen atoms from carbons 6 and 7 as numbered from the carboxy terminus of a fatty acid molecule to form an unsaturated bond.

A nucleic acid construct comprising a nucleotide sequence which encodes a polypeptide comprising the amino acid sequence depicted in SEQ ID NO:4, wherein said nucleotide sequence is operably associated with a transcription or an expression control sequence functional in a plant cell, wherein said nucleotide sequence encodes a functionally active polypeptide which removes hydrogen atoms from carbons 5 and 6 as numbered from the carboxy terminus of a fatty acid molecule to form an unsaturated bond.

A nucleic acid construct comprising a nucleotide sequence which encodes a functionally active desaturase having the amino acid sequence depicted in a SEQ ID NO:

• selected from the group consisting of SEQ ID NO:4, and SEQ ID NO:2, wherein said nucleotide sequence is operably associated with a promoter functional in a plant cell.

A microbial or plant host cell comprising at least one copy of a DNA sequence which encodes at least one functionally active Mortierella alpina fatty acid desaturase having an amino acid sequence as depicted in SEQ NO:

• selected from the group consisting of SEQ ID NO:2 and SEQ ID NO:4, wherein said cell or parent of said cell was transformed with a vector comprising said DNA sequence, and wherein said DNA sequence is operably associated with an expression control sequence.

An isolated or purified polynucleotide comprising the nucleotide sequence depicted in SEQ ID NO:

• 1 or SEQ ID NO:
• 3.

An isolated or purified nucleotide sequence encoding the polypeptide depicted in SEQ ID NO:

• 2 or SEQ ID NO:
• 4.

A method for obtaining altered long chain polyunsaturated fatty acid biosynthesis in a plant, said method comprising growing a plant having cells which contain one or more transgenes encoding a transgene expression product having an amino acid sequence depicted in a SEQ ID NO:

• selected from the group consisting of SEQ ID NO:4 and SEQ ID NO:2 which desaturates a fatty acid molecule at carbon 6 or carbon 12 from the carboxyl end of said fatty acid molecule, wherein said one or more transgenes is operably associated with an expression control sequence, under conditions whereby said one or more transgenes is expressed, whereby long chain polyunsaturated fatty acid biosynthesis in said cells is altered.