Olfactory and gustatory receptor genes in fig wasps: Evolutionary insights from comparative studies
Olfactory and gustatory receptor genes in fig wasps: Evolutionary insights from comparative studies
复制标题
无花果黄蜂的嗅觉和味觉受体基因：比较研究的进化见解
DOI：
10.1016/j.gene.2022.146953
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发表时间：
2022-10-15
期刊：
影响因子：
3.5
通讯作者：
Compton，Stephen G.
中科院分区：
文献类型：
--
作者：
Yu，Hui;Nong，Xiaojue;Compton，Stephen G.
榕小蜂化学感受机制在其与传粉榕树的共同进化关系中具有重要意义。我们使用的转录组序列的25个无花果小蜂在6个属，允许比较的方法来进化的关键分子组成部分的无花果小蜂化学感受：他们的气味（OR）和味觉（GR）受体基因。我们总共鉴定了311个OR和47个GR，每个物种记录了5 - 30个OR基因和1-4个GR基因。304个OR基因聚成18个邻位组，已知它们对表皮碳氢化合物（CHC）、信息素、酸、醇以及多种花香如桉树脑、芳樟醇和庚酮敏感。45个糖皮质激素受体基因聚为4个直链组，分别含有甜味受体、苦味受体、CO2受体和未知受体。除ORco（60.0%保守）和甜味受体（30.7%保守）外，其它大部分直链淀粉酶基因组的基因序列在种间差异很大。如低ω值所示，检测到气味和味觉基因的强纯化选择。在OR和GR正向组的基因座中均检测到正选择的标记。无花果黄蜂有相对较少的嗅觉，特别是味觉受体，反映了系统的自然历史。然而，不同物种之间的氨基酸序列差异显着，并与榕小蜂之间的系统发育关系是一致的。同一物种、不同宿主的一些直系同源群以及同一宿主的近缘种之间的ORs差异分别低至49.3%和9.8%，这意味着无花果小蜂可以迅速进化到新的生态环境。我们的研究结果提供了一个起点，了解无花果小蜂的化学感受系统的分子基础。
The mechanisms of chemoreception in fig wasps (Hymenoptera, Agaonidae) are of primary importance in their co-evolutionary relationship with the fig trees they pollinate. We used transcriptome sequences of 25 fig wasps in six genera that allowed a comparative approach to the evolution of key molecular components of fig wasp chemoreception: their odorant (OR) and gustatory (GR) receptor genes. In total, we identified 311 ORs and 47 GRs, with each species recording from 5 to 30 OR genes and 1–4 GR genes. 304 OR genes clustered into 18 orthologous groups known to be sensitive to cuticular hydrocarbons (CHC), pheromones, acids, alcohols and a variety of floral scents such as cineole, Linalool, and Heptanone. 45 GR genes clustered into 4 orthologous groups that contain sweet, bitter, CO2and undocumented receptors. Gene sequences in most orthologous groups varied greatly among species, except for ORco (60.0% conserved) and sweet receptors (30.7% conserved). Strong purifying selection of both odorant and gustatory genes was detected, as shown by low ω values. Signatures of positive selection were detected in loci from both OR and GR orthologous groups. Fig wasps have relatively few olfactory and especially gustatory receptors, reflecting the natural history of the system. Amino acid sequences nonetheless vary significantly between species and are consistent with the phylogenetic relationships among fig wasps. The differences in ORs within some orthologous groups from the same species, but different hosts and from closely related species from one host can reach as low as 49.3% and 9.8% respectively, implying the ORs of fig wasps can evolve rapidly to novel ecological environments. Our results provide a starting point for understanding the molecular basis of the chemosensory systems of fig wasps.