Pathogen exploitation of an abscisic acid- and jasmonate-inducible MAPK phosphatase and its interception by <i>Arabidopsis</i> immunity

Abstract

Significance Pathogens cause disease by deploying virulence effectors that interfere with various host targets, whereas plants counteract pathogen virulence when invoking a potent immunity known as effector-triggered immunity (ETI). Little is known about the mechanism underlying this molecular battle between plant immunity and pathogen virulence. We find that the phytohormones abscisic acid and jasmonate (JA), the signaling pathways of which are often exploited by pathogens, transcriptionally activate a common family of protein phosphatases that suppress immune-associated MAP kinases. We demonstrate that a bacterial pathogen exploits the JA-mediated suppression of MAP kinases by using a JA-mimic, whereas ETI blocks JA signaling to counteract this bacterial virulence. Our results highlight suppression and protection of MAP kinases as a molecular battle between pathogens and plants.