Lysophosphatidic Acid Acyltransferase from Coconut Endosperm Mediates the Insertion of Laurate at the sn-2 Position of Triacylglycerols in Lauric Rapeseed Oil and Can Increase Total Laurate Levels

摘要

Expression of a California bay laurel (Umbellularia californica) 12:0-acyl-carrier protein thioesterase, bay thioesterase (BTE), in developing seeds of oilseed rape (Brassica napus) led to the production of oils containing up to 50% laurate. In these BTE oils, laurate is found almost exclusively at the sn-1 and sn-3 positions of the triacylglycerols (T.A. Voelker, T.R. Hayes, A.C. Cranmer, H.M. Davies [1996] Plant J 9: 229–241). Coexpression of a coconut (Cocos nucifera) 12:0-coenzyme A-preferring lysophosphatitic acid acyltransferase (D.S. Knutzon, K.D. Lardizabal, J.S. Nelsen, J.L. Bleibaum, H.M. Davies, J.G. Metz [1995] Plant Physiol 109: 999–1006) in BTE oilseed rape seeds facilitates efficient laurate deposition at the sn-2 position, resulting in the acccumulation of trilaurin. The introduction of the coconut protein into BTE oilseed rape lines with laurate above 50 mol % further increases total laurate levels.