Uncovering roles of a glutathione S-transferase in the European honey bees, Apis mellifera

The European honey bee, Apis mellifera, is renowned for its honey production and vital role in pollinating a wide range of plants including both cultivated crops and wild flora. The contribution of honey bee is of paramount importance to the well-being of human societies and ecosystems. Unfortunately, in recent decades, honeybee health has been significantly challenged by various environmental stresses including diseases, limited nutrition, and xenobiotics. Numerous studies have provided significant insights into the acute toxicity, sublethal impacts and hormetic effects resulting from exposure to xenobiotics. Therefore, gaining a thorough understanding of the mechanisms underlying honeybee adaptation to xenobiotics becomes crucial. Glutathione S-transferases (GSTs) constitute a family of multifunctional enzymes that are ubiquitously present in both eukaryotes and prokaryotes, playing an important role in the detoxification of numerous endogenous and xenobiotic compounds. In this study, we structurally and functionally characterized an omega class GST enzyme, AmGSTO1 of honey bees with its roles in detoxification and antioxidative property. AmGSTO1 showed relatively higher expression in the fat body compared to other tissues in nurse bees. The antioxidative property of recombinant AmGSTO1 against known oxidative stress inducers was observed. The three-dimensional structure, enzyme kinetics, and substrate spectrum were also determined. Our results demonstrate that AmGSTO1 plays a significant role in the detoxifying of agrochemicals and secondary metabolites. Additionally, it has been observed to contribute to the alleviation of oxidative stress. Our findings conclusively suggest that AmGSTO1 is a crucial detoxification enzyme that plays a significant role in the xenobiotic adaptation of honeybees.