The Catalase Gene Contributes to Oxidative Stress Tolerance, Microsclerotia Formation, and Virulence in the Entomopathogenic Fungus .

Catalases play a crucial role in the metabolism of reactive oxygen species (ROS) by converting HO into molecular oxygen and water. They also contribute to virulence and fungal responses to various stresses. Previously, the -deletion mutant (Δ) was generated using the split-marker method in . In this study, the gene was identified, and its function was evaluated. Under normal culture conditions, there were no significant differences in colony growth or dimorphic switching between Δ and the wild-type (WT) strains. However, under oxidative stress, the colony growth was inhibited, and the yeast-hyphal transition was suppressed in the Δ strain. Hyperosmotic stress did not differ significantly between the two strains. In the Δ strain, microsclerotia (MS) formation was delayed, resulting in less uniform MS size and a 76% decrease in MS yield compared to the WT strain. Moreover, the Δ strain exhibited diminished virulence. Gene expression analysis revealed up-regulation of Δ, , and in the Δ strain. These findings indicate that the gene in is essential for oxidative stress tolerance, MS formation, and virulence.