A p53-like transcription factor, BbTFO1, contributes to virulence and oxidative and thermal stress tolerances in the insect pathogenic fungus, Beauveria bassiana

The p53-like transcription factor (TF) NDT80 plays a vital role in the regulation of pathogenic mechanisms and meiosis in certain fungi. However, the effects of NDT80 on entomopathogenic fungi are still unknown. In this paper, the NDT80 orthologue BbTFO1 was examined in Beauveria bassiana, a filamentous entomopathogenic fungus, to explore the role of an NDT80-like protein for fungal pest control potential. Disruption of BbTFO1 resulted in impaired resistance to oxidative stress (OS) in a growth assay under OS and a 50% minimum inhibitory concentration experiment. Intriguingly, the oxidation resistance changes were accompanied by transcriptional repression of the two key antioxidant enzyme genes cat2 and cat5. ΔBbTFO1 also displayed defective conidial germination, virulence and heat resistance. The specific supplementation of BbTFO1 reversed these phenotypic changes. As revealed by this work, BbTFO1 can affect the transcription of catalase genes and play vital roles in the maintenance of phenotypes associated with the biological control ability of B. bassiana.