Delta-15 desaturases suitable for altering levels of polyunsaturated fatty acids in oilseed plants and oleaginous yeast

摘要

The present invention relates to fungal Δ-15 fatty acid desaturases that are able to catalyze the conversion of linoleic acid (18:2, LA) to alpha-linolenic acid (18:3, ALA). Nucleic acid sequences encoding the desaturases, nucleic acid sequences which hybridize thereto, DNA constructs comprising the desaturase genes, and recombinant host plants and microorganisms expressing increased levels of the desaturases are described. Methods of increasing production of specific omega-3 and omega-6 fatty acids by over-expression of the Δ-15 fatty acid desaturases are also described herein.

主权项

1. A recombinant construct for altering the total fatty acid profile of mature seeds of an oilseed plant to produce an oil having an omega 3 to omega 6 ratio greater than 0.4, said construct comprising an isolated nucleic acid selected from the group consisting of:
(a) an isolated nucleic acid encoding all of the amino acid sequence as set forth in SEQ ID NOs: 2, 10 or 18; (b) an isolated nucleic acid encoding an amino acid sequence having at least 85% sequence identity based on the Clustal method of alignment with the amino acid sequences set forth in SEQ ID NOs: 2, 10 or 18; or (c) an isolated nucleic acid that is completely complementary to (a) or (b), wherein said isolated nucleic acid is operably linked to at least one regulatory sequence, and wherein said isolated nucleic acid of (a) or (b) encodes an amino acid sequence having Δ15 and Δ12 desaturase activity.