SN-1-ACYLGLYCEROL-3-PHOSPHATE ACYLTRANSFERASE OF ESCHERICHIA-COLI CAUSES INSERTION OF CIS-11 EICOSENOIC ACID INTO THE SN-2 POSITION OF TRANSGENIC RAPESEED OIL

The plsC gene of Escherichia coli encoding sn-1-acylglycerol-3-phospha te acyltransferase was modified by inserting an endoplasmic reticulum retrieval signal to its 3' end and introduced into rapeseed (Brassica napus L.) plants under the control of a napin promotor In developing s eeds from transgenic plants an sn-1-acylglycerol-3-phosphate acyltrans ferase activity was detectable which showed substrate specificities ty pical of the E. coli enzyme. Moreover, seed oil from the transformants unlike that from untransformed plants contained substantial amounts o f triacylglycerol species esterified with very-long-chain fatty acids at each glycerol position. Analysis of fatty acids at the sn-2 positio n of triacylglycerol showed hardly any very-long-chain fatty acids in untransformed plants, but in certain transformants these fatty acids w ere present, namely about 4% erucic acid and 9% eicosenoic acid. These data demonstrate that the bacterial acyltransferase can function in d eveloping rapeseed and alters the stereochemical composition of transg enic rape seed oil by directing very-long-chain fatty acids, especiall y cis-11 eicosenoic acid, to its sn-2 position.