Department of Molecular and Cellular Biology, University of California, Davis, CA 95616.
Invasive Insect Biocontrol and Behavior Laboratory, Plant Science Institute, US Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705.
Proc Natl Acad Sci U S A. 2018 Jan 23;115(4):714-719. doi: 10.1073/pnas.1718284115. Epub 2018 Jan 8.
Pheromones and other semiochemicals play a crucial role in today's integrated pest and vector management strategies. These semiochemicals are typically discovered by bioassay-guided approaches. Here, we applied a reverse chemical ecology approach; that is, we used olfactory proteins to lead us to putative semiochemicals. Specifically, we used 7 of the top 10 odorant receptors (ORs) most expressed in the antennae of the southern house mosquito, , and which are yet to be deorphanized. We expressed these receptors in the oocyte recording system and challenged them with a panel of 230 odorants, including physiologically and behaviorally active compounds. Six of the ORs were silent either because they are not functional or a key odorant was missing. CquiOR36, which showed the highest transcript levels of all genes in female antennae, was also silent to all odorants in the tested panel, but yielded robust responses when it was accidentally challenged with an old sample of nonanal in ethanol. After confirming that fresh samples were inactive and through a careful investigation of all possible "contaminants" in the old nonanal samples, we identified the active ligand as acetaldehyde. That acetaldehyde is activating CquiOR36 was further confirmed by electroantennogram recordings from antennae of fruit flies engineered to carry CquiOR36. Antennae of female mosquitoes also responded to acetaldehyde. Cage oviposition and dual-choice assays demonstrated that acetaldehyde is an oviposition attractant in a wide range of concentrations and thus of potential practical applications.
信息素和其他化学生态物质在当今综合虫害和病媒管理策略中起着至关重要的作用。这些化学生态物质通常是通过生物测定指导的方法发现的。在这里，我们采用了反向化学生态学方法；也就是说，我们使用嗅觉蛋白来引导我们发现潜在的化学生态物质。具体来说，我们使用了 10 种在南方家蚊触角中表达量最高的气味受体（OR）中的 7 种，而这 7 种 OR 尚未被去孤儿化。我们将这些受体在卵母细胞记录系统中表达，并使用包括生理和行为活性化合物在内的 230 种气味物质对其进行了挑战。其中 6 种 OR 沉默，要么是因为它们没有功能，要么是因为缺少关键气味物质。在雌性触角中，CquiOR36 的转录水平最高，在测试的所有气味物质中也没有反应，但当用乙醇中的非那醇旧样本意外挑战时，它会产生强烈的反应。在确认新鲜样本不活跃并仔细调查旧非那醇样本中所有可能的“污染物”之后，我们确定了活性配体是乙醛。乙醛激活 CquiOR36 进一步通过携带 CquiOR36 的果蝇的触角电触角图记录得到证实。雌性蚊子的触角也对乙醛有反应。笼产卵和双选择试验表明，乙醛在广泛的浓度范围内是一种产卵引诱剂，因此具有潜在的实际应用价值。
