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Two Subunits of the Rpd3 Histone Deacetylase Complex of Cochliobolus heterostrophus Are Essential for Nitrosative Stress Response and Virulence, and Interact With Stress-Response Regulators ChHog1 and ChCrz1

Summary

Scientists discovered that two proteins called ChPho23 and ChSds3 help a fungus that causes corn disease survive attacks by the plant’s immune system. These proteins work together with other cellular signals to help the fungus protect itself from harmful nitrogen-based compounds. When these proteins are removed, the fungus becomes weaker and less able to infect corn plants, suggesting these proteins could be potential targets for developing new fungicides.

Background

Southern corn leaf blight (SCLB) caused by Cochliobolus heterostrophus is a destructive maize disease. Reactive nitrogen species derived from nitric oxide exhibit antimicrobial activities against pathogens, but the regulatory mechanisms underlying adaptation to nitrosative stress remain largely unexplored in C. heterostrophus.

Objective

To identify and characterize components of the Rpd3 histone deacetylase complex involved in nitrosative stress response and virulence in C. heterostrophus, and to elucidate their interactions with stress-response regulators ChHog1 and ChCrz1.

Results

ChPho23 and ChSds3 were identified as essential components of the Rpd3 complex required for vegetative growth, conidiation, and virulence. Both proteins directly interact with ChHog1, which in turn interacts with the transcription factor ChCrz1. ChCrz1 regulates expression of nitrosative stress response genes ChGSNOR and ChFHB. Deletion mutants showed increased sensitivity to nitrosative stress and significantly reduced virulence on maize leaves.

Conclusion

ChPho23 and ChSds3 are crucial for fungal growth, conidiation, nitrosative stress response, and virulence in C. heterostrophus through their interactions with ChHog1 and ChCrz1. These findings provide insights into Rpd3 complex-Hog1-Crz1 signaling and could inform strategies for controlling southern corn leaf blight.
  • Published in:Molecular Plant Pathology,
  • Study Type:Experimental Study,
  • Source: PMID: 40773473, DOI: 10.1111/mpp.70131
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