() Could Inhibit the Proliferation of Nucleopolyhedrovirus through Promoting Apoptosis.

β-1,3-glucan recognition proteins (βGRPs) as pattern recognition receptors (PRRs) play an important role in recognizing various pathogens and trigger complicated signaling pathways in insects. In this study, we identified a β-1,3-glucan recognition protein gene named , which showed differential expression, from a previous transcriptome database. The full-length cDNA sequence was 1244 bp, containing an open reading frame (ORF) of 1128 bp encoding 375 amino acids. was strongly expressed in the larval stages and highly expressed in the midgut of larvae in particular. After BmNPV infection, the expression of was reduced significantly in the midgut. Furthermore, a significant increase in the copy number of BmNPV was observed after the knockdown of in 5th instar larvae, while the overexpression of suppressed the proliferation of BmNPV in BmN cells. Subsequently, the expression analysis of several apoptosis-related genes and observation of the apoptosis morphology demonstrated that overexpression of facilitated apoptosis induced by BmNPV in BmN cells. Moreover, positively regulated the phosphatase and tensin homolog gene (), while expression of the inhibitor of apoptosis gene () was negatively regulated by BmβGRP4. Hence, we hypothesize that BmNPV infection might suppress and facilitate to inhibit cell apoptosis by downregulating the expression of to escape host antiviral defense. Taken together, these results show that may play a role in response to BmNPV infection and lay a foundation for studying its functions.