Method for the production of γ-linolenic acid and/or stearidonic acid in transgenic Brassicaceae and Linaceae

A method of producing γ-linolenic acid (18:3Δ6,9,12) or stearidonic acid (18:4Δ6,9,12,15) or a method of producing γ-linolenic acid (18:3Δ6,9,12) and stearidonic acid (18:4Δ6,9,12,15) in a transgenic plant, wherein the transgenic plant comprises at least 10% by weight of oleic acid based on the total fatty acid content and wherein the method comprises:

• a) introducing, into a plant, a nucleic acid sequence which codes for a Δ6-desaturase,
• b) expressing, in the plant, the nucleic acid sequence which codes for a Δ6-desaturase, and
• c) growing and harvesting the plant,
• wherein the nucleic acid sequence which codes for a Δ6-desaturase comprises:
• i) the nucleic acid sequence of SEQ ID NO:
• 1,
• ii) a nucleic acid sequence which, as the result of the degeneracy of the genetic code, can be derived from the amino acid sequence of SEQ ID NO:
• 2, or
• iii) a nucleic acid sequence which codes for a polypeptide having at least 95% homology with the amino acid sequence of SEQ ID NO:
• 2 and having Δ6-desaturase activity,
• wherein the Δ6-desaturase encoded by said nucleic acid sequence has a substrate specificity for α-linolenic acid which is more than 20 times higher than the substrate specificity for linoleic acid,
• and wherein the plant is selected from the group consisting of plants of the family Brassicaceae or Linaceae, soya, oilseed rape, and sunflower.