TOWARDS THE GENETIC-ENGINEERING OF TRIACYLGLYCEROLS OF DEFINED FATTY-ACID COMPOSITION - MAJOR CHANGES IN ERUCIC-ACID CONTENT AT THE SN-2 POSITION AFFECTED BY THE INTRODUCTION OF A 1-ACYL-SN-GLYCEROL-3-PHOSPHATE ACYLTRANSFERASE FROM LIMNANTHES DOUGLASII INTO OIL SEED RAPE

A cDNA encoding a 1-acyl-sn-glycerol-3-phosphate acyltransferase from Limnanthes douglasii was introduced into oil seed rape (Brassica napus ) under the control of a napin promoter. Seed triacylglycerols from tr ansgenic plants were analysed by reversed-phase HPLC and trierucin was detected at a level of 0.4% and 2.8% in two transgenic plants but was not found in untransformed rape seed. Total fatty acid composition an alysis of seeds from these selected plants revealed that the erucic ac id content was no higher than the maximum found in the starting popula tion. Analysis of fatty acids at the sn-2 position showed no erucic ac id in untransformed rape but in the selected transgenic plants 9% (mol /mol) and 28.3% (mol/mol) erucic acid was present, These results concl usively demonstrate that the gene from L. douglasii encodes a 1-acyl-s n-glycerol-3-phosphate acyltransferase which can function in rape and incorporate erucic acid at the sn-2 position of triacylglycerols in se ed, Additional modifications may further increase levels of trierucin.