Changes in Kennedy pathway intermediates associated with increased triacylglycerol synthesis in oil-seed rape

The rates of triacylglycerol synthesis in maturing oil-seed rape (Brassica napus cv Shiralee) were manipulated by light/dark treatments. Under conditions of high lipid accumulation the amounts of the Kennedy pathway intermediates, phosphatidate and particularly, diacylglycerol were increased significantly. At the same time there were no significant changes in the activities of the four pathway enzymes, of which diacylglycerol acyltransferase had the lowest detectable activity. The alteration in carbon flux was accompanied by some changes in the acyl quantity of the diacylglycerol pool but not in that of other intermediates. The results provide additional evidence for our proposal that diacylglycerol acyltransferase can exert significant flux control at times of high lipid accumulation in oil-seed rape.