PLC2 REGULATES MAMP-TRIGGERED IMMUNITY BY MODULATING ROS PRODUCTION IN ARABIDOPSIS.

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

Buenos Aires

Congreso; Reunión conjunta de Sociedades de Biociencias; 2017

Sociedades de biociencias de Argentina (SAIC, SAIB, SAB, etc)

The activation of phosphoinositide-specific phospholipaseC (PI-PLC) is one of the earliest responses triggered bythe recognition of several microbe-associated molecular patterns(MAMPs) in plants. The Arabidopsis PI-PLC gene family is composedof nine members. Previous studies suggested a role for PLC2in MAMP-triggered immunity (MTI) as it is rapidly phosphorylated invivo upon treatment with the bacterial MAMP flg22. Here weanalyzed the role of PLC2 in plant immunity using an artificial microRNAto silence PLC2 expression in Arabidopsis. We found thatPLC2-silenced plants are more susceptible to the type III secretionsystem-deficient bacterial strain Pseudomonas syringae pv. tomato(Pst) DC3000 hrcC-and to the non-adapted pea powdery mildewErysiphe pisi. However, PLC2-silenced plants display normal susceptibilityto virulent and avirulent P. syringae strains. Ion leakageanalysis showed that silenced lines conserve typical hypersensitiveresponse features. In response to flg22, PLC2-silenced plantsmaintain wild-type MAPK activation and PHI1, WRKY33 and FRK1immune marker gene expression.In leaf disc using peroxidase/luminolbased method we found that silenced lines have reduced reactiveoxygen species (ROS) production. ROS -dependent responsessuch as callose deposition and stomatal closure were analyzed byoptical microscopy showing a compromised response in the silencedlines. FLAG-tagged immunoprecipitation of NADPH oxidase(RbohD) showed that PLC2 was associated, suggesting its potentialregulation of a branch of MTI and non-host resistance that involvesearly ROS-regulated processes. We are currently analyzing whetherPLC2 is specific for flg22 responses or it is also involved in the perceptionof other MAMPs such as chitin or Elf18. Additionally, we arealso measuring Ca2+ cytosolic increases upon MAMPs treatments inPLC2-silenced lines using transgenic plants expressing an aequorinreporter.