Induced systemic resistance by plant growth-promoting rhizobacteria.

Abstract

Rhizobacteria are present in large numbers on the root surface, where plant exudates and lysates provide nutrients. Selected strains of beneficial, plant growthpromoting rhizobacteria (PGPR) trigger a plant-mediated induced systemic resistance (ISR) response that is effective against a broad spectrum of plant pathogens. To study the molecular basis of ISR, an Arabidopsis thaliana-based model was developed, using PGPR strain Pseudomonas fluorescens WCS417r as the inducing agent. Genetic dissection of the ISR signalling pathway revealed that ISR is regulated by a defence pathway in which the phytohormones jasmonic acid and ethylene play key roles.