Molecular and Functional Characterization of Odorant-Binding Protein Genes in an Invasive Vector Mosquito, Aedes albopictus

Aedes albopictus is a major vector of dengue and Chikungunya viruses. Olfaction plays a vital role in guiding mosquito behaviors and contributes to their ability to transmit pathogens. Odorant-binding proteins (OBPs) are abundant in insect olfactory tissues and involved in the first step of odorant reception. While comprehensive descriptions are available of OBPs from Aedes aegypti, Culex quinquefasciatus and Anopheles gambiae, only a few genes from Ae. albopictus have been reported. In this study, twenty-one putative AalbOBP genes were cloned using their homologues in Ae. aegypti to query an Ae. albopictus partial genome sequence. Two antenna-specific OBPs, AalbOBP37 and AalbOBP39, display a remarkable similarity in their overall folding and binding pockets, according to molecular modeling. Binding affinity assays indicated that AalbOBP37 and AalbOBP39 had overlapping ligand affinities and are affected in different pH condition. Electroantennagrams (EAG) and behavioral tests show that these two genes were involved in olfactory reception. An improved understanding of the Ae. albopictus OBPs is expected to contribute to the development of more efficient and environmentally-friendly mosquito control strategies.白纹伊蚊（Aedes albopictus）是登革病毒与基孔肯雅病毒的主要传播媒介。嗅觉在调控蚊虫行为、助力其传播病原体的过程中发挥至关重要的作用。气味结合蛋白（Odorant-binding proteins, OBPs）大量富集于昆虫嗅觉组织，参与气味识别的初始步骤。当前针对埃及伊蚊（Aedes aegypti）、致倦库蚊（Culex quinquefasciatus）及冈比亚按蚊（Anopheles gambiae）的OBPs已有全面的研究阐释，但关于白纹伊蚊的相关OBP基因仅见少量报道。本研究以埃及伊蚊的OBP同源基因为检索探针，对白纹伊蚊的部分基因组序列进行比对分析，成功克隆得到21个推定的AalbOBP基因。分子建模结果显示，两种触角特异性气味结合蛋白AalbOBP37与AalbOBP39在整体折叠结构与配体结合口袋方面呈现出极高的相似性。结合亲和力实验表明，AalbOBP37与AalbOBP39具有重叠的配体结合谱，且其结合活性受不同pH环境的影响。触角电图（Electroantennagrams, EAG）检测与行为学实验证实，这两个基因参与了嗅觉识别过程。深入解析白纹伊蚊OBPs的功能机制，有望为开发更高效且环境友好的蚊虫防控策略提供理论支撑。