Physiological and Molecular Characterization of Allyl Isothiocyanate Adaptation in the Formosan Subterranean Termite,...

The Formosan subterranean termite, Coptotermes formosanus is a globally distributed species that feeds on lignocellulose and causes substantial economic losses annually. Currently control strategy heavily relies on chemical pesticides, raising concerns about environmental impacts associated with their extensive use. Allyl isothiocyanate (AITC), a plant-derived compound, has demonstrated potent insecticidal activity against insect pests. However, its physiological and molecular effects in C. formosanus remain poorly understood. In this study, transcriptome data were used to identify antioxidant, detoxification, and neural-related genes, followed by phylogenetic analysis. C. formosanus was treated with AITC at LC₅₀ for 24 h, after which enzyme activities and gene expression profiles were assessed. AITC exposure significantly increased the activities of glutathione S-transferase (GST), carboxylesterase (CarE), acetylcholinesterase (AChE), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), accompanied by differential regulation of corresponding gene families. POD genes showed coordinated transcriptional and enzymatic induction, whereas SOD genes displayed isoform-specific responses with strong induction of mitochondrial CfSOD2 homologs. The detoxification-related genes CfGSTS1 and CfGSTO1 were significantly upregulated. Molecular docking and dynamics simulations further indicated dynamic interaction between AITC and CfGSTS1, providing structural evidence for a potential interaction that may be relevant to AITC detoxification. Together, these findings advance our understanding of the physiological and molecular responses of C. formosanus to AITC exposure and provide a basis for further evaluation of AITC as a potential alternative termite control agent.