Suppression of host defense in compatible plant– Pseudomonas syringae interactions

Despite impressive advances in the study of plant resistance to pathogens, little is known about the molecular basis of plant susceptibility to virulent pathogens. Recent progress in susceptible plant– Pseudomonas syringae interactions has provided a glimpse into the battles fought between plants and bacterial pathogens. A key step for pathogenesis appears to be the suppression of host defenses. Suppression of host defenses, including basal defense, gene-for-gene resistance and nonhost resistance, is a key step for pathogenesis. Defense suppression is mediated by bacterial effector proteins, which are secreted through the type III secretion system, and by coronatine, a bacterial toxin that structurally and functionally mimics methyl jasmonate, a plant defense signaling molecule.