The OsAGO2-miR11337-5p-OsLRR Module Confers Rice Resistance to Rhizoctonia solani by Modulating Vitamin B6 Biosynthesis.

Argonaute (AGO) proteins play a pivotal role in small RNA (sRNA)-mediated RNA silencing and plant immunity. However, their roles in rice defense against sheath blight remain largely unknown. In this study, we found that the osago2 mutant exhibited enhanced resistance to Rhizoctonia solani (R. solani). Small RNA sequencing revealed that miR11337-5p, an OsAGO2-associated sRNA, was significantly upregulated upon R. solani infection. OsLRR, which encodes a leucine-rich repeat protein, was identified as the direct target of miR11337-5p. Functional analyses demonstrated that miR11337-5p negatively regulated rice resistance to R. solani, whereas OsLRR positively regulated rice resistance to rice sheath blight. Furthermore, OsLRR interacted with OsPDX1.1 (pyridoxal 5'-phosphate synthase subunit), a key vitamin B6 biosynthesis protein, and enhanced its protein stability. We further confirmed that vitamin B6 regulated plant immunity via a dual mechanism: direct inhibition of R. solani pathogenicity and induction of systemic immunity. Together, these findings reveal a novel immune mechanism mediated by the OsAGO2-miR11337-5p-OsLRR module, providing new insights into plant protection via vitamin B6 regulation.