ABSTRACT
Many unusual fatty acids present in the seed oils of non-food plants are modified at the ?12 position either by the addition of epoxy or hydroxy groups or by the formation of triple (acetylenic) bonds or conjugated double bonds. The introduction of these functionalities into C18 fatty acids is catalyzed by a family of divergent forms of the fatty-acid ?12-desaturase (FAD2) enzyme. Genes encoding these enzymes have now been cloned from a variety of organisms and expressed in transgenic oilseeds. However,the accumulation of the intended fatty acids in transgenic plants has been relatively disappointing,and the mechanisms of these unusual fatty acids biosynthesis and transferring from phosphatidylcholine into storage triacylglycerols still need to be elucidated.
