Pathogen-induced reactive oxygen species (ROS) act as key signaling molecules in plant immunity, but their integration with epigenetic regulation remains unclear. Here, we identify the rice (Oryza sativa) histone deacetylase OsHDA705 as a redox sensor that coordinates immunity through oxidative post-translational modifications (PTMs). Pathogen-induced ROS oxidizes OsHDA705 at cysteine 256 (C256), blocking its deacylase activity. This oxidation promotes hyperacylation of the transcription factor OsIPA1 and histones, thereby activating defense gene expression. We further show that the catalase OsCATB functions as a redox mediator, reducing oxidized OsHDA705 to restore its deacetylase activity, thereby re-establishing the suppression of immunity. The fungal pathogen Ustilaginoidea virens hijacks this process via the secreted effector UvSE1, which physically interacts with the host catalase OsCATB to boost its ROS-scavenging activity, thereby reducing the oxidation level of OsHDA705. Genetic disruption of the OsCATB-OsHDA705 module enhances broad-spectrum disease resistance. Our findings reveal a pathogen strategy to reprogram the host's redox-epigenetic regulation and establish reversible histone deacetylase oxidation as a molecular switch regulating immune transcription in plants.
Yuan Fang, Rui Wang, Yuhang Duan et al.· The Plant Cell· 0 citations
Rice (Oryza sativa) is highly susceptible to a variety of devastating fungal diseases. However, whether these phylogenetically distinct fungal pathogens employ conserved effectors to disrupt common immune hubs remains unclear. Here, we identify a conserved virulence strategy in which multiple rice-infecting fungal pathogens employ a subtilisin-like protease effector, SBT1, to suppress host immunity. Upon secretion into plant cells, SBT1 directly targets the key immune signaling component OsMAPKKKα and mediates its degradation in a proteolytic activity-dependent manner. OsMAPKKKα acts in a linear signaling cascade: it is phosphorylated and stabilized by OsRLCK185 at Thr493, and subsequently phosphorylates OsMKK4 to activate downstream MAPK signaling. By degrading OsMAPKKKα, SBT1 disrupts the chitin-triggered immune signaling transduced through the OsCERK1–OsRLCK185–OsMAPKKKα–OsMKK4 module. Importantly, host-induced gene silencing (HIGS) targeting SBT1 confers broad-spectrum resistance against multiple fungal pathogens. Our study unveils a previously unexplored pathogen strategy wherein a secreted effector protease dismantles a central signaling node, and identifies OsMAPKKKα as a promising target for engineering disease-resistant crops.
Yuan Fang, Zhaoyun Wang, Wenjing Li et al.· Science Advances· 0 citations
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