USE OF TRANSGENIC PLANTS AND MUTANTS TO STUDY THE REGULATION AND FUNCTION OF LIPID-COMPOSITION

Mutants and transgenic plants with altered expression of genes implica ted in lipid metabolism are providing fresh insights into the regulati on and function of lipid composition. To date, several genes encoding fatty acid desaturases, acyltransferases, a thioesterase, a lipid tran sfer protein and an isoform of acyl-carrier protein have been introduc ed into transgenic plants. Despite the fact that some of these transge nic plants had large alterations in lipid composition, they showed sur prisingly little phenotypic variation from wild-type plants. Although detailed analyses of these plants are just beginning, several theories regarding the roles of particular genes in various plant processes, s uch as cold tolerance and transfer of lipids between membranes, have b een either substantiated or discarded on the basis of the data already obtained. In addition, constructs that contain the promoter regions o f genes implicated in lipid metabolism fused to reporter genes have be en introduced into transgenic plants and are providing some clues as t o how lipid composition is regulated.