Functional Characteristics, Electrophysiological and Antennal Immunolocalization of General Odorant-Binding Protein 2 in Tea Geometrid, Ectropis obliqua.

As one of the main lepidopteran pests in Chinese tea plantations, Warren (tea geometrids) can severely decrease yields of tea products. The olfactory system of the adult tea geometrid plays a significant role in seeking behaviors, influencing their search for food, mating partners, and even spawning grounds. In this study, a general odorant-binding protein (OBP) gene, , was identified in the antennae of using reverse transcription quantification PCR (RT-qPCR). Results showed that was more highly expressed in the antennae of males than in females relative to other tissues. The recombinant GOBP2 protein was prepared in and then purified through affinity chromatography. Ligand-binding assays showed that GOBP2 had a strong binding affinity for some carbonyl-containing tea leaf volatiles (e.g., ()-2-hexenal, methyl salicylate, and acetophenone). Electrophysiological tests confirmed that the male moths were more sensitive to these candidate tea plant volatiles than the female moths. Immunolocalization results indicated that GOBP2 was regionally confined to the sensilla trichoid type-II in the male antennae. These results indicate that GOBP2 may be primarily involved in the olfactory activity of male moths, influencing their ability to sense tea leaf volatiles. This study provides a new perspective of insect GOBPs and implies that olfactory function can be used to prevent and control the tea geometrid.