Isolation of a native strain of Clonostachys rosea with insecticidal, antiphytopathogenic, and endophytic activities.

Clonostachys rosea is a promising biocontrol fungus with multitrophic activity, yet effective native isolates with broad-spectrum potential remain limited. Here, we report the isolation and characterization of a novel soil-derived C. rosea strain, GY24, which exhibits potent entomopathogenic, antiphytopathogenic, and endophytic properties. Morphological and phylogenetic analyses confirmed its taxonomic identity, and optimal growth and sporulation were achieved on Oatmeal agar (OMA) medium. GY24 displayed high compatibility with chemical insecticides and strong tolerance to osmotic and cell wall stress, although it was sensitive to heat and UV exposure. In virulence assays against Galleria mellonella, GY24 caused up to 97% mortality within 84 h (LT₅₀ = 51.78 h), with characteristic mycosis symptoms and hyphal outgrowth. In dual-culture assays, GY24 significantly inhibited key phytopathogens, including Fusarium graminearum, Alternaria alternata, and Bipolaris maydis, and suppressed F. graminearum infection in cherry tomato fruit. Furthermore, GY24 established endophytic colonization in wheat, promoting plant growth and enhancing resistance to Fusarium-induced root rot. GY24-treated wheat displayed increased chlorophyll and lycopene levels and elevated superoxide dismutase (SOD) and catalase (CAT) activities, indicating improved photosynthetic performance and oxidative stress resilience. Collectively, these findings highlight the scientific significance of strain GY24 as a multitrophic biocontrol agent with integrated insecticidal, antifungal, and plant-beneficial functions. Its broad-spectrum activity and compatibility with agrochemicals make it a strong candidate for sustainable crop protection and integrated pest and disease management strategies.