A Phytophthora capsici virulence effector associates with NPR1 and suppresses plant immune responses

Salicylic acid (SA) plays a crucial regulatory role in plant immunity. NPR1 (non-expressor of pathogenesis related-1) is a SA receptor and plays a pivotal role in SA signaling. However, pathogen effectors which target NPR1 to promote infection have rarely been reported. Here, we identified a Phytophthora capsici effector RxLR48 that associates with NPR1, facilitates P. capsici infection and is required for pathogen virulence. Furthermore, we demonstrated that RxLR48 promotes NPR1’s nuclear localization and inhibits its proteasome-mediated degradation, suggesting that RxLR48 suppresses SA signaling by targeting the central regulator NPR1. In addition, we showed that RxLR48 also suppresses pattern-triggered immunity (PTI). Together, our research indicates that P. capsici suppresses plant immunity by targeting SA and PTI pathways.