The biosynthesis and roles of N-acylethanolamines in plants

Abstract

N -acylethanolamines (NAEs) are a group of lipid signaling molecules derived from the phospholipid precursor N -acylphosphatidylethanolamine (NAPE). NAEs can be processed by a wide range of metabolic processes including hydrolysis by fatty acid amide hydrolase (FAAH), peroxidation by lipoxygenases (LOX), and conjugation by glycosyl- and malonyl-transferases. The diversity of NAE metabolites points to participation in multiple downstream pathways for regulation and function. NAEs with acyl chains of 18C are typically the most predominant types in vascular plants. Whereas in nonvascular plants and some algae, the arachidonic acid-containing NAE, anandamide (a functional “endocannabinoid” in animal systems), was recently reported. A signaling role for anandamide and other NAEs is well established in vertebrates, while NAEs and their oxylipin metabolites are recently becoming appreciated for lipid mediator roles in vascular plants. Here, the NAE metabolism and function in plants are overviewed, with particular emphasis on processes described in vascular plants where most attention has been focused.