Poster: Lipids & related molecules

Abs # 303: N-acylethanolamines. Lipid mediators of plant growth and development

Presenter:	Motes, Christy M., cmmotes@noble.org
Authors	Motes, Christy M. (A)   Teaster, Neal  (B)   Chapman, Kent D. (B)   Blancaflor, Elison B. (A)
Affiliations:	(A): The Samuel Roberts Noble Foundation (B): University of North Texas

N-Acylethanolamines (NAEs) are lipid mediators derived from the hydrolysis of the membrane phospholipid, N-acylphosphatidylethanolamine (NAPE). In animal systems, this reaction constitutes part of the “endocannabinoid” signaling pathway, which regulates a variety of physiological processes, including cell proliferation, immune cell signaling, neurotransmission, and embryo development. NAEs have been identified and quantified in a variety of plant tissues, and are particularly prevalent in desiccated seeds; however, these NAEs are metabolized to barely detectable levels during imbibition. Here we show that sustained levels of NAE12:0 have profound effects on Arabidopsis root growth and development. Light and electron microscopic analysis of Arabidopsis roots reveal that the effects of NAE12:0 also are apparent at the cellular level. NAE12:0 is a potent inhibitor of phospholipase D alpha and has been shown to prevent ABA induced stomatal closure. Interestingly, antisense suppressed PLD alpha seedlings recovered slowly from exogenous NAE application. In mammalian systems, NAE-mediated responses are reversed by antagonists of cannabinoid receptors. We are testing whether specific plant processes, which are influenced by NAE such as ABA induced stomatal closure and seedling development, can be reveresed by similar antagonists. Collectively, our data point to a possible role for NAEs as negative regulators of seed germination, seedling growth and ABA mediated responses, and emphasize the importance of understanding the metabolic regulation of the levels of this endogenous class of lipid mediators (Supported by NASA NAG2-1518 to EBB, USDA-NRICGP agreement number 2002-35318-12571 to KDC and the Noble Foundation).