Suppression of miR2871 enhances rice resistance to bacterial blight by modulating cell wall biosynthesis.

MicroRNAs (miRNAs) are known to play critical roles in plant immunity. However, their roles and molecular mechanisms in coordinating plant immunity and growth remain poorly characterized. Here, we report a rice-specific miRNA, osa-miR2871a-3p (miR2871), negatively regulates rice resistance to Xanthomonas oryzae pv oryzae (Xoo) by modulating cell wall biosynthesis. We demonstrated that the transcription factor OsWRKY72 directly binds to the OsMIR2871 promoter and activates its expression. miR2871 suppresses cell wall biosynthesis by directly targeting OsGT43G, which encodes an endoplasmic reticulum-localized glycosyltransferase protein. Genetic and physiological analysis revealed that both miR2871-downregulating (STTM2871) and OsGT43G-overexpressing (GT43G-ox) plants exhibit enhanced resistance to Xoo by maintaining a high level of cellulose and lignin content. Furthermore, we suggested that OsGT43G stabilizes OsMYB63 through physical interactions, co-activating OsCesA4/7/9 expression to confer rice resistance to Xoo. Finally, phenotypic assays showed that STTM2871, GT43G-ox, and OsWRKY72 knockout (wrky72-ko) lines confer broad-spectrum resistance to Xoo without yield penalty. Collectively, our findings uncover a rice-specific miRNA and provide novel insights into the role of the OsWRKY72-miR2871-OsGT43G module in mediating rice's response to Xoo, which offers a new strategy to improve rice resistance to bacterial pathogens.