Silencing the β-glucan recognition protein enhanced the pathogenicity of Cordyceps fumosorose against Hyphantria cunea Drury larvae

The β-glucan recognition protein (βGRP) plays a crucial role in pathogen recognition by insects, thereby activating their innate immunity. However, the immune response of βGRP in Hyphantria cunea Drury (Lepidoptera: Noctuidae), an invasive pest of forests and agriculture, to pathogens remains unclear. In this study, we identified a new isolate of the entomopathogenic fungus Cordyceps fumosorosea. We found C. fumosorosea exhibits significant pathogenicity against H. cunea larvae. Based on the transcriptome, we found that the βGRP genes of H. cunea can be induced to express after infection by C. fumosorosea. βGRP1 is primarily expressed in the fat body and significantly upregulated by 11.23-fold at 12 h post-infection with C. fumosorosea. Besides, molecular docking showed a potential binding interaction between βGRP1 protein and β-1,3-glucans, which is further confirmed by protein-carbohydrate binding assays. Additionally, the knockdown of βGRP1 through RNA interference increases the mortality of H. cunea larvae following C. fumosorosea infection. Taken together, our study underscores the critical role of βGRP1 in the immune response to C. fumosorosea infection and suggests an integrated pest management strategy that combines entomopathogenic fungi with RNA interference technology as an effective approach for controlling H. cunea.