ABSTRACT Colletotrichum asianum, the cause of mango anthracnose, is a major threat to mango production worldwide. However, the mechanisms underlying plant invasion by C. asianum are poorly understood. Mini‐chromosomes are increasingly recognised as indispensable components in the virulence of plant‐pathogenic fungi. Here, we identify CaMutA, a secreted glycoside hydrolase 71 effector encoded on a mini‐chromosome, as a critical pathogenicity factor that suppresses plant immune responses and is essential for infection by C. asianum. CaMutA directly interacts with the mango chitinase MiChi1. When heterologously expressed in Arabidopsis thaliana , MiChi1 confers enhanced resistance against multiple pathogens, suggesting its role in plant defence, a process that CaMutA subverts. Together, our findings uncover that a mini‐chromosome‐encoded effector can subvert plant immunity by directing the ubiquitin‐mediated degradation of conserved defence‐related chitinases. This study thus identifies promising targets for controlling mango anthracnose.
Rui Wang, Tong-Tong Zhu, Rong Huang et al.· Molecular plant pathology· 0 citations
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
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