Larval Metabolic and Physiological Mechanisms Underlying Resistance to Chinese Sacbrood Virus in Apis cerana

CSBV is a major pathogen threatening the health of A. cerana, but the mechanisms underlying natural resistance in its larval host remain poorly understood. To elucidate this, we established resistant (R) and susceptible (S) larval phenotypes through controlled CSBV inoculation and combined untargeted metabolomics with biochemical assays. Metabolomic profiling revealed a markedly disrupted metabolic state in S larvae, with 8272 differential metabolites compared to controls, versus a more moderate response in R larvae 4208 metabolites. Key pathways, including galactose and glycerophospholipid metabolism, were significantly perturbed. Crucially, R larvae exhibited a profoundly enhanced antioxidant defense in the gut, with activities of catalase, glutathione S-transferase, and superoxide dismutase being 2.5-fold, 1.5-fold, and 2.0-fold higher, respectively, than in S larvae. Our findings demonstrate that CSBV resistance is linked to a modulated metabolic response and a robust, activated antioxidant system, providing new insights into host-pathogen interactions and potential strategies for safeguarding pollinator health.