ABSTRACT
The B. napus β-ketoacyl-Acyl carrier protein reductase was down-regulated using antisense in order to study effects on seed lipid accumulation or leaf membrane biosynthesis. As part of the study, these workers developed a new assay and examined the relationship between the activity of the reductase, leaf expansion and overall fatty acid synthesis. Except for the brief period when storage material in seeds provides carbon for fatty acid synthesis during germination, photosynthesis produces the precursor molecules required. Glucose 6-phosphate can enter the plastid via a specific transporter and contribute to starch and fatty acid synthesis as well as being used for the oxidative pentose phosphate pathway. Acetyl-CoA carboxylase catalyses the first committed step in fatty acid synthesis. The lack of build-up of intermediates during fatty acid synthesis suggests that the condensing enzymes may be important for controlling overall flux. In most plants, oleate and palmitate are the major products of fatty acid synthesis in plastids.
