GH16 Glycoside Hydrolases Divergently Contribute to Fungal Development, Stress Tolerance, and Virulence of an Insect Fungal Pathogen

Fungal glycoside hydrolases (GHs) include β-glucanases and glycosyltransferases, which are involved in fungal cell wall metabolism and crucial for fungal development and adaptation to varied environments and host niches. However, many GHs in entomopathogenic fungi (EPF) have not been well characterized. Here, 13 detectably expressed members of the GH16 family were systemically and genetically characterized in the EPF Beauveria bassiana. Ten and nine proteins were differently involved in cell wall β-glucan metabolism and chitin assembly/metabolism, respectively. Eight to twelve members were differently associated with conidiation, conidial morphology, germination, response to cell wall/membrane stresses, and fungal virulence, in which contributions of nine members to conidial germination and/or stress response were correlated to their roles in virulence. Five virulence-related members were involved in evasion of insect immune defense response via reducing different pathogen-associated molecular patterns, β-1,3-glucan. As a result, GH16 members divergently contribute to fungal development, stress response, and virulence via orchestrating cell wall remodeling.