Poster: Intercellular Signaling

Abs # 799: Phospholipid Signaling in Plant Response to H2O2: the Oleate-Stimulated Phospholipase D and Phosphatidic Acid Increase Arabidopsis Resistance to H2O2-Induced Cell Death

Presenter:	Wang, Xuemin , wangs@ksu.edu
Authors	Wang, Xuemin  (A)   Zhang, Wenhua  (A)   Qin, Chunbo  (A)   Wang, Cunxi  (A)   Gudrum, Olafsdottir  (A)   Wood, Tara  (A)
Affiliations:	(A): Kansas State University

Hydrogen peroxide (H2O2) is a pivotal signaling molecule involved in various stress responses, but cellular components mediating plant response to H2O2 are not well defined. Hydrolysis of common membrane phospholipids occurs under many stress conditions, but the cellular functions of such hydrolysis are not fully understood. Here we show that the plasma membrane-bound, oleate-stimulated phospholipase D, PLDdelta, and its lipid product phosphatidic acid (PA) play a protective role in Arabidopsis response to H2O2-promoted cell death and stress damages. The Arabidopsis genome has 12 PLD genes, and knockout of PLDdelta abolishes specifically the oleate-stimulated PLD activity. H2O2 treatment of Arabidopsis cells activates PLD activity, and ablation of PLDdelta results in the loss of the H2O2–induced activation of PLD. PLDdelta-null leaves and cells display increased sensitivity to H2O2-induced programmed cell death and display increased susceptibility to stress. Further manipulation indicates that the PLDdelta-derived PA functions to antagonize the effect of H2O2 on promoting cell death and that PA may mediate the effect by altering protein phosphorylation. Results from this study suggest that PLDdelta and its resultant PA play a positive role in plant stress tolerance and survival.