PLC2 Regulates MAMP-Triggered Immunity by Modulating ROS Production in Arabidopsis

ALVAREZ, MARIA ELENA; LAMATTINA, LORENZO; COUTO, DANIEL; LAXALT, ANA M; ANDERSSON, MATS X.; SCUFFI, DENISE; D'AMBROSIO, JUAN MARTÍN; ZIPFEL, CYRIL; MUNNIK, TEUN; FABRO, GEORGINA

PLANT PHYSIOLOGY.

AMER SOC PLANT BIOLOGISTS

Año: 2017

0032-0889

Theactivation of phosphoinositide-specific phospholipase C (PI-PLC) is one of theearliest responses triggered by recognition of several microbe-associatedmolecular patterns (MAMPs) in plants. The Arabidopsis PI-PLC gene family iscomposed of nine members. Previous studies suggested a role for the PLC2 inMAMP-triggered immunity (MTI) as it is rapidly phosphorylated in vivo upon treatment with thebacterial MAMP flg22. In this study, we analyzed the role of PLC2 in plant immunity using an artificial microRNA to silence thePLC2 expression in transgenic plants. We found that PLC2-silenced plants were more susceptible to the type III secretion system-deficient strain Pseudomonas syringae pv. tomato(Pst) DC3000 hrcC- (Pst DC3000 hrcC-)and to the non-adaptedpea powdery mildew Erysiphe pisi.However, PLC2-silenced plants had normalsusceptibility to virulent (Pst DC3000) and avirulent (Pst DC3000AvrRPM1) P. syringae strains,conserving some typical HR features. In response to flg22, the PLC2-silenced plants maintain wild typeMAPK activation and PHI1, WRKY33 and FRK1 gene expression, but reduced reactive oxygen species (ROS)-dependentresponses such as callose deposition and stomatal closure. Accordingly, thegeneration of ROS uponflg22 treatment was compromised in the PLC2-defficientplants suggesting an effect of PLC2 in a branch ofMTI and non-host resistance that involves early ROS-regulated processes.Consistently, PLC2 associates with RBOHD, evidencing a putative regulation ofthe Arabidopsis NADPH oxidase by PLC2.