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A Zn2-Cys6 transcription factor, TgZct4, reprograms antioxidant activity in the fungus Trichoderma guizhouense to defend against oxidative stress

Summary

Trichoderma guizhouense is a fungus used to protect plants from harmful pathogens. Researchers discovered that a special protein called TgZct4 acts like a master switch that activates the fungus’s defense system against harmful reactive oxygen molecules. When the fungus encounters stress, TgZct4 turns on genes that produce protective enzymes called catalases and superoxide dismutases, helping the fungus survive. This discovery could help scientists create even more effective biological pest control products.

Background

Trichoderma guizhouense is a biocontrol fungus with strong viability and notable resistance to oxidative stress. While fungi have evolved strategies to cope with oxidative stress, the mechanisms governing antioxidant response specificity remain poorly understood. This study characterizes a previously unidentified antioxidant-related Zn2-Cys6 transcription factor, TgZct4, in T. guizhouense.

Objective

To identify and characterize novel transcription factors involved in oxidative stress response in T. guizhouense, particularly those mediating resistance to hydrogen peroxide. To determine the role of TgZct4 in regulating antioxidant defense mechanisms and understand how it reprograms cellular responses to both low and high concentrations of H2O2.

Results

TgZct4 expression positively correlates with H2O2 concentrations and localizes to the nucleus under oxidative stress. Deletion of Tgzct4 resulted in 31.89% increased inhibition rates at 10 mM H2O2 compared to wild-type. TgZct4 regulates catalase genes TgCat1 and TgCat2, with TgCat2 being a direct target. The catalases provide protection against oxidative stress independently or in conjunction with each other.

Conclusion

TgZct4 functions as a key positive regulator of antioxidant response in T. guizhouense through reprogramming of classic antioxidant enzymes including catalases, superoxide dismutases, and peroxidases. This work reveals novel mechanisms of fungal stress tolerance and provides insights for potential genetic enhancement of this biocontrol agent.
  • Published in:Communications Biology,
  • Study Type:Experimental Research,
  • Source: PMID: 41094151, DOI: 10.1038/s42003-025-08864-5
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