Inhibition of insect olfactory behavior by an airborne antagonist of the insect odorant receptor co-receptor subunit.
Inhibition of insect olfactory behavior by an airborne antagonist of the insect odorant receptor co-receptor subunit.
复制标题
DOI：
10.1371/journal.pone.0177454
复制
发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Luetje CW
中科院分区：
文献类型：
--
作者：
Kepchia D;Moliver S;Chohan K;Phillips C;Luetje CW
对多变的环境化学感觉线索的反应是昆虫生存所必需的。气味受体（OR）家族是一类重要的检测挥发性分子的受体；引导昆虫寻找食物、配偶和产卵地点。ORs是气味门控离子通道，由一个可变的气味特异性亚基和一个保守的气味受体共受体（Orco）亚基组成，其化学计量未知。Orco亚基具有一个变构位点，调节剂可以结合并非竞争性地抑制Orco的气味激活。在这项研究中，我们表征了几种卤素取代的苯噻吩甲酰胺Orco拮抗剂结构。采用双电极电压钳电生理法测定黑腹果蝇和致倦库蚊卵母细胞中表达的Orco拮抗剂活性。一种化合物OX1w也被证明可以抑制一组冈比亚按蚊（Anopheles gambiae）被不同气味剂激活的嗅觉激活。接下来，我们询问Orco拮抗剂OX1w是否会影响昆虫的嗅觉行为。黑腹果蝇幼虫趋化试验被用来解决这个问题。在封闭的实验室内，幼虫被高度稀释的乙酸乙酯强烈吸引。对乙酸乙酯的吸引依赖于Orco，也需要气味特异性亚基Or42b。在实验室内加入气载Orco拮抗剂OX1w可消除幼虫对乙酸乙酯的趋化性。Orco拮抗剂不是感觉行为的一般抑制剂，因为来自光源的行为排斥不受影响。这是第一次证明空气中的Orco拮抗剂可以改变昆虫的嗅觉行为。这些结果提示了一种新的昆虫防治方法，并强调了开发更有效的Orco拮抗剂的必要性。
Response to volatile environmental chemosensory cues is essential for insect survival. The odorant receptor (OR) family is an important class of receptors that detects volatile molecules; guiding insects towards food, mates, and oviposition sites. ORs are odorant-gated ion channels, consisting of a variable odorant specificity subunit and a conserved odorant receptor co-receptor (Orco) subunit, in an unknown stoichiometry. The Orco subunit possesses an allosteric site to which modulators can bind and noncompetitively inhibit odorant activation of ORs. In this study, we characterized several halogen-substituted versions of a phenylthiophenecarboxamide Orco antagonist structure. Orco antagonist activity was assessed on ORs from Drosophila melanogaster flies and Culex quinquefasciatus mosquitoes, expressed in Xenopus laevis oocytes and assayed by two-electrode voltage clamp electrophysiology. One compound, OX1w, was also shown to inhibit odorant activation of a panel of Anopheles gambiae mosquito ORs activated by diverse odorants. Next, we asked whether Orco antagonist OX1w could affect insect olfactory behavior. A Drosophila melanogaster larval chemotaxis assay was utilized to address this question. Larvae were robustly attracted to highly diluted ethyl acetate in a closed experimental chamber. Attraction to ethyl acetate was Orco dependent and also required the odorant specificity subunit Or42b. The addition of the airborne Orco antagonist OX1w to the experimental chamber abolished larval chemotaxis towards ethyl acetate. The Orco antagonist was not a general inhibitor of sensory behavior, as behavioral repulsion from a light source was unaffected. This is the first demonstration that an airborne Orco antagonist can alter olfactory behavior in an insect. These results suggest a new approach to insect control and emphasize the need to develop more potent Orco antagonists.