From omics to enhanced fungal virulence: Overexpression of a putative secreted protein improves Beauveria bassiana biocontrol potential against the insect pests Piezodorus guildinii and Tenebrio molitor

The entomopathogenic fungus Beauveria bassiana is widely used as a biocontrol agent, but its efficacy varies depending on the target insect species . Piezodorus guildinii , a major soybean pest, exhibits low susceptibility to B. bassiana . Thus, biocontrol of this pest requires improving virulence of B. bassiana . Here, we used genomic and transcriptomic analyses to identify novel genes associated with the enhanced virulence of B. bassiana strain ILB308 when exposed to the insect epicuticular hydrocarbon n-pentadecane. Comparative analysis with the lower-virulence strain ILB205 revealed differentially expressed genes (DEGs) linked to genetic information process pathways and immune evasion. Among these DEGs, we identified BbCBM9_1 , a secreted carbohydrate-binding protein, as a candidate virulence factor. Overexpression of BbCBM9_1 in ILB205 led to enhanced virulence against P. guildinii and Tenebrio molitor , as well as improved conidial germination, tolerance to oxidative and cell wall stress, and increased growth in nutrient-rich and glycerol-supplemented media. This demonstrates that the enhanced virulence observed in ILB308 grown on n-pentadecane can be replicated by overexpressing an associated gene in a low-virulence strain. Our study, highlights the potential of integrating transcriptomics and targeted genetic modifications to optimize fungal biocontrol agents for improved pest management.