The Transcription Factor OsWRKY30 Regulates Rice Resistance to Southern Rice Black Streaked Dwarf Virus Disease

WRKY transcription factors are important plant regulators that participate in diverse biotic and abiotic stress responses. However, their roles in resistance to Southern rice black-streaked dwarf virus (SRBSDV) remain unknown. Previous work demonstrated that the histone deacetylase gene OsHDA706 (LOC_Os06g37420) enhances SRBSDV resistance by promoting jasmonic acid (JA) biosynthesis. In this study, we first confirmed that the rice line GR216 exhibits strong resistance to SRBSDV through artificial inoculation. Knockout of OsHDA706 in GR216 led to typical SRBSDV symptoms, including dwarfing, dark-green wrinkled leaves, and inverted fibrous roots, confirming its role in antiviral defense. Using the RiceTFtarget database and yeast one-hybrid experiments, we identified OsWRKY30 (LOC_Os08g38990) as a potential upstream regulator of OsHDA706. Co-expression analysis based on the CARFI-Rice database revealed that the expression pattern of OsWRKY30 closely resembles that of several disease-resistance-related WRKY genes under biotic stress and hormone treatments. CRISPR-Cas9 knockout of OsWRKY30 in GR216 resulted in strong symptoms after inoculation with SRBSDV, supporting its involvement in antiviral immunity. RNA sequence (RNA-seq) analysis further showed that OsWRKY30 expression was significantly down-regulated in mutants after SRBSDV infection, and that defense response, stress response, and salicylic acid signaling pathways were significantly enriched in both wild-type and mutant plants. Hormone quantification revealed that JA levels were markedly higher in wild-type than in oswrky30 mutants. Collectively, these results demonstrate that OsWRKY30 positively regulates rice resistance to SRBSDV, likely by modulating JA biosynthesis. This study provides new insights into the molecular mechanisms of rice antiviral defense and offers valuable genetic resources for breeding SRBSDV-resistant cultivars.