Abstract:

The oomycete pathogen Phytophthora sojae is a causal agent of soybean root rot. Upon colonization of soybeans, P. sojae secretes various RXLR effectors to suppress host immune responses, supporting successful infection. Previous research has demonstrated that the RXLR effector Avh94 functions as a virulence effector, but the molecular mechanism underlying its role in virulence remains unknown. Here, we demonstrate that Avh94 overexpression in plants and pathogens promotes Phytophthora infection. Avh94 interacts with soybean JAZ1/2, which is a repressor of jasmonic acid (JA) signaling. Avh94 stabilizes JAZ1/2 to inhibit JA signaling and silencing of JAZ1/2 enhances soybean resistance against P. sojae. Moreover, P. sojae lines overexpressing Avh94 inhibit JA signaling. Furthermore, exogenous application of methyl jasmonate improves plant resistance to Phytophthora. Taken together, these findings suggest that P. sojae employs an RXLR effector to hijack JA signaling and thereby promote infection.