Evolution of insect olfactory receptors.
Evolution of insect olfactory receptors.
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DOI：
10.7554/elife.02115
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发表时间：
2014-03-26
期刊：
影响因子：
7.7
通讯作者：
Grosse-Wilde E
中科院分区：
文献类型：
--
作者：
Missbach C;Dweck HK;Vogel H;Vilcinskas A;Stensmyr MC;Hansson BS;Grosse-Wilde E
嗅觉检测过多的行为相关的气味分子，参与嗅觉的基因家族在不同的动物门表现出高度的多样性。昆虫使用嗅觉（OR）或离子型受体（IR）以及在某些情况下味觉受体（GR）来检测挥发性分子。虽然IR在原口门的嗅觉器官中表达，但OR被假设为对陆生昆虫生活方式的适应。本文研究了无翅刺尾虫Lepismachilisy-signata（Archaeognatha）、火毛热蝉Thermobiastritica（Zygentoma）和新翅目叶虫Phylliumsiccifolium（Phasmatodea）的嗅觉系统。OR和嗅觉辅助受体（Orco）是非常高的概率缺乏Lepismachilis，在Thermobia我们已经确定了三个Orco候选人，并在Phyllium一个完全发达的OR/Orco为基础的系统。我们认为，ORs并没有出现作为一个适应陆地生活方式，但后来在昆虫进化中演变，与Orco出现之前的ORs。http://dx.doi.org/10.7554/eLife.02115.001检测化学信号对昆虫来说可能是生死攸关的问题，许多昆虫使用三个受体蛋白家族来检测各种气味。这些受体家族之一的成员，嗅觉受体，与另一种蛋白质形成复合物，嗅觉辅助受体对定位和稳定受体以及实际功能都是必不可少的。甲壳类动物与昆虫有着共同的祖先，由于它们没有嗅觉受体，因此有人提出这些受体是在史前昆虫从海洋迁移到陆地上生活时进化出来的。根据这一观点，嗅觉受体的进化是因为这些祖先需要能够检测漂浮在空气中而不是溶解在水中的气味分子。以前对昆虫嗅觉受体的研究主要集中在有翅膀的昆虫身上。Missbach等人现在已经使用了广泛的技术来研究进化上更古老的无翅昆虫群体如何探测气味。由于所有被调查的群体都是在不同的时间从一个共同的祖先进化而来的，这些实验可以跟踪嗅觉受体的历史发展。在与飞行昆虫更密切相关的无翅物种中，有证据表明存在多种辅助感受器，但不是嗅觉感受器本身。在最基础的昆虫中，没有发现嗅觉受体系统的任何部分，这表明在昆虫从水迁移到陆地很久之后，主要的嗅觉受体独立于辅助受体进化。Missbach等人认为，嗅觉受体的发展要晚得多，大约在维管植物传播和昆虫发展飞行能力的时候。DOI：http://dx.doi.org/10.7554/eLife.02115.002网站
The olfactory sense detects a plethora of behaviorally relevant odor molecules; gene families involved in olfaction exhibit high diversity in different animal phyla. Insects detect volatile molecules using olfactory (OR) or ionotropic receptors (IR) and in some cases gustatory receptors (GRs). While IRs are expressed in olfactory organs across Protostomia, ORs have been hypothesized to be an adaptation to a terrestrial insect lifestyle. We investigated the olfactory system of the primary wingless bristletail Lepismachilis y-signata (Archaeognatha), the firebrat Thermobia domestica (Zygentoma) and the neopteran leaf insect Phyllium siccifolium (Phasmatodea). ORs and the olfactory coreceptor (Orco) are with very high probability lacking in Lepismachilis; in Thermobia we have identified three Orco candidates, and in Phyllium a fully developed OR/Orco-based system. We suggest that ORs did not arise as an adaptation to a terrestrial lifestyle, but evolved later in insect evolution, with Orco being present before the appearance of ORs. DOI: http://dx.doi.org/10.7554/eLife.02115.001 Detecting chemical cues can be a matter of life or death for insects, and many employ three families of receptor proteins to detect a broad range of odors. Members of one of these receptor families, the olfactory receptors, form a complex with another protein, the olfactory coreceptor that is essential for both positioning and stabilizing the receptor, as well as the actual function. Crustaceans share a common ancestor with insects, and since they do not have olfactory receptors it has been proposed that these receptors evolved when prehistoric insects moved from the sea to live on land. According to this idea, olfactory receptors evolved because these ancestors needed to be able to detect odor molecules floating in the air rather than dissolved in water. Previous research on insect olfactory receptors has focused on insects with wings. Missbach et al. have now used a wide range of techniques to investigate how evolutionarily older wingless insect groups detect scents. As all investigated groups evolved from a common ancestor at different times these experiments allow tracking of the historical development of olfactory receptors. In the wingless species that is more closely related to the flying insects there was evidence of the presence of multiple coreceptors but not the olfactory receptors themselves. In the most basal insects no evidence for any part of the olfactory receptor-based system was found. This indicates that the main olfactory receptors evolved independently of the coreceptor long after the migration of insects from water to land. Missbach et al. suggest that olfactory receptors instead developed far later, around the time when vascular plants spread and insects developed the ability to fly. DOI: http://dx.doi.org/10.7554/eLife.02115.002