The Pseudomonas syringae effector AvrPtoB targets abscisic acid signaling pathway to promote its virulence in Arabidopsis

Abstract

Phytohormones play an essential role in plant immune responses. Many phytopathogens secret effector proteins to promote infection and plant hormone signaling pathways are considered to be the potential targets of effectors. Here we found that abscisic acid (ABA) signaling was activated rapidly upon infection with Pseudomonas syringae pv. tomato (Pst). Pst secretes the effector AvrPtoB to target ABA 8′-hydroxylase CYP707As for degradation in Arabidopsis thaliana. CYP707As hydroxylate ABA to an inactive form. The degradation of CYP707As resulted in ABA accumulation and compromised plant immune responses. Our study demonstrated that Pst could hijack the key components of Arabidopsis ABA signaling pathway to cause disease.