This research will determine how desaturation of membrane lipid fatty acids is regulated. Because it has not been possible to characterize most of the membrane-bound enzymes which catalyze fatty acid desaturation by conventional methods, the small family of genes encoding the desaturases will be cloned. The cloned genes and antibodies against the products of these genes will then be used to measure the amount of desaturase gene products and to examine the effect on membrane lipid composition of quantitative variation in the amount of desaturase in transgenic plants. The proposed approach will exploit a unique collection of mutants of Arabidopsis with alterations in fatty acid desaturation to facilitate the isolation and characterization of the family of desaturase genes. Fatty acid unsaturation is a determinant of the quality and economic value of the product from oilseed species. Because of the importance of nutritional fatty acids from plants in human health it would be advantageous to be able to control the degree of unsaturation of the lipids in the harvested tissue of crop species so that they can be tailored to meet our nutritional needs. This could be extremely cost effective. Many conceivable mechanisms of understanding of how the desaturases act, how they are regulated, and having the relevant genes in hand. Inasmuch as the same enzymes appear to regulate both membrane and storage lipid composition, the goals of this proposal represent tangible steps in this direction.
