A screen for plant genes induced by flagellin and repressed by pathogen effectors identifies a cell wall-associated kinase involved in immunity

ROSLI, HERNÁN GUILLERMO; ZHEN, YI; POMBO, MARINA ALEJANDRA; BOMBARELY AURELIANO; FEI, ZHANGJUN; COLLMER, ALAN; MARTIN, GREGORY

Buenos Aires

Simposio; 32nd New Phytologist Symposium; 2013

Microbe-associated molecular patterns (MAMPs) such as those present in bacterial flagellin are powerful inducers of the innate immune response in plants. Pathogens deliver virulence proteins, termed effectors, into the plant cell where they interfere with the immune response and promote disease. Here we describe a high-throughput screen using RNA-Seq and virus-induced gene silencing (VIGS) to identify tomato genes whose expression is enhanced by the flagellin MAMP flgII-28 but reduced by host intracellular activities of the Pseudomonas syringae pv. tomato (Pst) type III effectors AvrPto and AvrPtoB. Gene ontology terms for this category of flagellin-induced, repressed by effectors (FIRE) genes showed it to be enriched for genes encoding certain subfamilies of protein kinases and transcription factors. Thirty-three of the 110 protein kinase-encoding FIRE genes were subjected to VIGS and their involvement in pattern-triggered immunity was tested with a simple leaf-based assay. Silencing of one FIRE gene, encoding a cell wall-associated kinase (SlWak1), compromised the immune response resulting in enhanced growth of Pst and extensive disease symptoms. By relying on the pathogen to define a subset of host genes this experimental approach identified candidates for playing an important role in the plant immune system.