Bombyx mori Trehalase 2 Activates Energy Metabolism to Resist Fenpropathrin in Silkworm, Bombyx mori

The extensive use of pesticides poses a significant threat to sericulture, yet effective control strategies are still limited. Trehalose, the primary sugar in insect hemolymph, is a key player in abiotic stress responses and its metabolism is regulated by trehalase. Despite this, the role of the Bombyx mori trehalase 2 (BmTreh2) in the response to the pyrethroid insecticide remains unexplored. In this study, comparative analysis revealed significant differences in BmTreh2 expression among silkworm (Bombyx mori) strains with varying resistance levels to fenpropathrin, suggesting a potential role of this gene in fenpropathrin resistance. At the cellular level, overexpression of BmTreh2 increased tolerance to fenpropathrin, whereas RNAi-mediated knockdown of BmTreh2 decreased cell viability under fenpropathrin exposure. These results demonstrate that BmTreh2 plays a critical role in mediating fenpropathrin resistance. Furthermore, correlation analysis between BmTreh2 and key energy metabolism-related genes, including lactate dehydrogenase (LDH), alanine aminotransferase (ALT), malate dehydrogenase (MDH), and isocitrate dehydrogenase (IDH), revealed a significant positive correlation with MDH and IDH expression, and a negative correlation with LDH and ALT. This study elucidates key molecular mechanisms underlying silkworm resistance to fenpropathrin, establishing a theoretical framework for molecular breeding of resistant silkworm strains and informing integrated pest management strategies.