Characterization\nof Four Carboxylesterases Involved\nin Detoxification of β‑Cypermethrin, λ‑Cyhalothrin,\nand Malathion in <i>Helicoverpa armigera</i>

Helicoverpa armigera Hübner\n(Lepidoptera: Noctuidae) is a globally devastating pest and has evolved\nwith varying levels of resistance to a broader spectrum of insecticides.\nCarEs are major enzymes involved in insecticide detoxification and\nmetabolic resistance. Four <i>CarE</i> genes were identified\nand cloned from H. armigera, and the\nexpression pattern analyses indicated that they were predominantly\nexpressed in the detoxifying tissues and larval feeding periods. The\ninsecticide inductive assays further suggested that these <i>CarE</i> genes with expressions were significantly upregulated\nafter <i>beta</i>-cypermethrin, <i>lambda</i>-cyhalothrin,\nmalathion, and chlorpyrifos exposures. The purified recombinant proteins\nof both CarE016B and CarE016C by bacterial expression exhibited significantly\nhigher catalytic efficiency toward α-naphthyl acetate and also\nshowed relatively stronger binding with both β-cypermethrin\nand λ-cyhalothrin compared to the CarE006C and CarE015A. In\nvitro metabolism assay with HPLC suggests that CarE016B and CarE016C\nhave the ability to metabolize β-cypermethrin, λ-cyhalothrin,\nand malathion with varying hydrolase activities. GC-MS/MS analysis\nidentified 3-phenoxybenzaldehyde (3-PBAld) as the metabolite of both\nβ-cypermethrin and λ-cyhalothrin. Homology modeling and\nmolecular docking analyses further indicate that these three types\nof insecticides could be anchored into the active pocket of both CarEs.\nCollectively, these results demonstrate that both CarE016B and CarE016C\nplay a critical role in the detoxification of pyrethroid and organophosphate\ninsecticides in H. armigera. This study\nprovides the foundations for a comprehensive understanding of the\nrole of the CarEs family in insecticide detoxification and resistance\nin H. armigera.