Tissue Expression and Characterization of Eogystia hippophaecolus (Lepidoptera: Cossidae) Odorant Receptors

Eogystia hippophaecolus (Hua, Chou, Fang et Chen) is a drilling pest that damages sea buckthorn, leading to substantial ecological and economic losses in areas where sea buckthorn is cultivated in China. Pheromone lures are widely used to monitor and trap male moths; however, the olfactory recognition mechanisms in male moths require further investigation. In this study, we characterized odorant receptor genes using phylogenetics, gene expression, sequence analyses and molecular docking. A phylogenetic analysis using the maximum likelihood method revealed that odorant receptor co-receptor (EhipOrco) genes clustered with other lepidopteran Orco genes, while pheromone receptor (EhipPR) genes clustered with other lepidopteran PR genes, suggesting that these genes have similar functions. The expression levels of 27 odorant receptor (EhipOR) genes in five tissues of male adults were analyzed using qPCR. Nine EhipOR genes were specifically expressed in the antennae, while several EhipOR genes were highly expressed in the head, feet, and external genitalia. As determined using molecular docking, EhipPR1–3 bound strongly to the primary sex pheromone components of E. hippophaecolus. Additionally, EhipPR1–3 demonstrated a strong binding affinity for longifolene among sea buckthorn volatiles. This study provides a foundation for future functional research on EhipORs and the olfactory recognition mechanisms of E. hippophaecolus.