Cloning and functional characterization of the fatty acid elongase 1 (FAE1) gene from high erucic Crambe abyssinica cv. Prophet.

A genomic fatty acid elongation 1 (FAE1) clone was isolated from Crambe abyssinica. The genomic clone corresponds to a 1521-bp open reading frame, which encodes a protein of 507 amino acids. In yeast cells expression of CrFAE led to production of new very long chain monounsaturated fatty acids such as eicosenoic (20:1(delta11)) and erucic (22:1(delta13)) acids. Seed-specific expression in Arabidopsis thaliana resulted in up to a 12-fold increase in the proportion of erucic acid. On the other hand, in transgenic high-erucic Brassica carinata plants, the proportion of erucic acid was as high as 51.9% in the best transgenic line, a net increase of 40% compared to wild type. These results indicate that the CrFAE gene encodes a condensing enzyme involved in the biosynthesis of very long-chain fatty acids utilizing monounsaturated and saturated acyl substrates, with a strong capability for improving the erucic acid content.