Department of Biology, Baylor University, Waco, TX 76706, USA.
Chem Senses. 2022 Jan 1;47. doi: 10.1093/chemse/bjac032.
Insects rely on olfactory receptors to detect and respond to diverse environmental chemical cues. Detection of semiochemicals by these receptors modulates insect behavior and has a direct impact on species fitness. Volatile organic compounds (VOCs) are released by animals and plants and can provide contextual cues that a blood meal host or nectar source is present. One such VOC is linalool, an enantiomeric monoterpene, that is emitted from plants and bacteria species. This compound exists in nature as one of two possible stereoisomers, (R)-(-)-linalool or (S)-(+)-linalool. In this study, we use a heterologous expression system to demonstrate differential responsiveness of a pair of Anopheline odorant receptors (Ors) to enantiomers of linalool. The mosquitoes Anopheles gambiae and Anopheles stephensi encode single copies of Or29 and Or53, which are expressed in the labella of An. gambiae. (S)-(+)-linalool activates Or29 orthologs with a higher potency than (R)-(-)-linalool, while the converse is observed for Or53 orthologs. The conservation of these receptors across a broad range of Anopheline species suggests they may function in the discrimination of linalool stereoisomers, thereby influencing the chemical ecology of mosquitoes. One potential application of this knowledge would be in the design of novel attractants or repellents to be used in integrated pest management practices.
昆虫依赖嗅觉受体来检测和响应各种环境化学线索。这些受体对信息素的检测调节昆虫的行为，直接影响物种的适应能力。挥发性有机化合物（VOCs）由动物和植物释放，可以提供存在血餐宿主或花蜜来源的上下文线索。一种这样的 VOC 是芳樟醇，一种对映单萜，它是从植物和细菌物种中释放出来的。这种化合物在自然界中存在两种可能的立体异构体，（R）-（-）-芳樟醇或（S）-（+）-芳樟醇。在这项研究中，我们使用异源表达系统来证明一对按蚊气味受体（Ors）对芳樟醇对映体的反应差异。蚊子冈比亚按蚊和斯蒂芬斯按蚊分别编码 Or29 和 Or53 的单个拷贝，它们在冈比亚按蚊的唇瓣中表达。（S）-（+）-芳樟醇对 Or29 同源物的激活作用比（R）-（-）-芳樟醇更强，而对于 Or53 同源物则观察到相反的情况。这些受体在广泛的按蚊物种中的保守性表明它们可能在芳樟醇对映异构体的识别中发挥作用，从而影响蚊子的化学生态学。这方面知识的一个潜在应用可能是设计新型的引诱剂或驱避剂，用于综合害虫管理实践。
