OsGF14d promotes oxidation of BSR-D1 to regulate rice blast resistance

Post-translational modifications are crucial for regulating biological processes and stress responses in plants, yet oxidative modifications-particularly on methionine residues-remain largely unknown in the context of plant immunity. Previously, we identified the rice (Oryza sativa L.) transcription factor Broad-spectrum resistance Digu 1 (BSR-D1) as a key player in broad-spectrum blast resistance. Here, we report a mechanism by which a 14-3-3 protein, OsGF14d, interacts with BSR-D1 and promotes its oxidation at methionine 187 (M187) upon Magnaporthe oryzae infection. This oxidation enhances BSR-D1's DNA-binding affinity and transcriptional activity toward genes involved in hydrogen peroxide (H₂O₂) degradation, thereby modulating redox homeostasis and disease outcomes. Strikingly, knockout of OsGF14d increased H₂O₂ accumulation and strongly enhanced blast resistance without compromising plant growth. We further demonstrate that OsGF14d facilitates BSR-D1 oxidation through an acidic microenvironment created by residues Glu9, Glu50, and Glu51. Mutating M187 disrupted oxidative activation and diminished transcriptional output, underscoring the functional importance of this modification. Our findings reveal a regulatory layer in plant immunity, wherein pathogen-induced oxidative modification fine-tunes transcription factor activity. This study also positions OsGF14d as a promising target for breeding disease-resistant crops with maintained yield.