Introduction

All organisms synthesize fatty acids, which are long-chain aliphatic carboxylic acids.  Fatty acids are used primarily as precursors for glycerolipids, a family of lipids containing a glycerol backbone that are essential components of cellular membranes.  In plants, this pathway is additionally important because some fatty acids are elongated in a related series of reactions to produce suberin and cuticular waxes.  These are critical protective compounds on leaf and stem surfaces.  Breakdown products of fatty acids are also widely used as intracellular signaling molecules as part of cellular responses to external stimuli.  Herbicide inhibition of either fatty acid synthesis or elongation prevents the production of these important molecules and thus is lethal to plants. 

This discussion of plant fatty acid synthesis and its herbicide inhibitors is divided into two sections: 

1. the synthesis of fatty acids up to 18-carbon chain lengths, and their elongation and modification to create lipids, waxes, and suberin; and
2. the herbicide inhibitors of fatty acid synthesis and elongation, and mechanisms of resistance.