Perception of a bacterial quorum sensing signal activates a tripartite plant immune strategy

How sessile plants perceive QS for defense is unclear. Here, we show that Arabidopsis thaliana perceives 2'-aminoacetophenone (2’-AA), a volatile QS signal from Pseudomonas aeruginosa, through cell surface pattern recognition receptor (PRR) complexes, resulting in multistrategic defense and disease resistance.

The 2’-AA-induced plant immunity requires chemical and genetic specificity. 2’-AA binds to the cytoplasmic domain of BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1) and induces the formation of PRR complexes that initiate the plant immune responses. 2’-AA stimulates plant exudation of acetic acid, a volatile compound that effectively quenches QS and inhibits P. aeruginosa virulence. Plants exposed to 2’-AA reshaped the root microbiome by suppressing the abundant Pseudomonad taxa with increased bacterial diversity.