Rice RLI1b normally binds to theSERK4promoter, maintaining plant development and regulating the SERK4-P3IP1-NRPD1a pathway. However, RGSV P3, a viral protein, competes with RLI1b forSERK4promoter binding, activatingSERK4expression. Once activated, SERK4 phosphorylates P3IP1, enhancing its E3 ligase activity. This leads to increased ubiquitination and degradation of NRPD1a, a key player in antiviral defense. Consequently, the accelerated degradation of NRPD1a results in the development of a pathogenic phenotype in rice, disrupting its natural defenses against viral infections. Thus, through competitive binding and pathway activation, RGSV P3 effectively manipulates plant physiology to promote viral pathogenesis.
