Wang Qian, Wen Xiaojian, Lu Yi, Wen Junbao
Beijing Key Laboratory for Forest Pests Control, College of Forestry, Beijing Forestry University, Beijing, China.
Front Physiol. 2021 Apr 20;12:661310. doi: 10.3389/fphys.2021.661310. eCollection 2021.
The tree-of-heaven root weevil () and the tree-of-heaven trunk weevil () are closely related species that monophagously feed on the same host plant, the (Mill) Swingle, at different locations. However, the mechanisms of how they select different parts of the host tree are unclear. As chemosensory systems play important roles in host location and oviposition, we screened candidate chemosensory protein genes from the transcriptomes of the two weevils at different developmental stages. In this study, we identified 12 candidate chemosensory proteins (CSPs) of and , three EscrCSPs, and one EbraCSPs, respectively, were newly identified. The qRT-PCR results showed that EscrCSP7/8a/9 and EbraCSP7/8/9 were significantly expressed in adult antennae, while EscrCSP8a and EbraCSP8 shared low sequence identity, suggesting that they may respond to different odorant molecule binding. Additionally, EbraCSP6 and EscrCSP6 were mainly expressed in antennae and proboscises and likely participate in the process of chemoreception. The binding simulation of nine volatile compounds of the host plant to EscrCSP8a and EbraCSP8 indicated that (1R)-(+)-alpha-pinene, (-)-beta-caryophyllene, and beta-elemen have higher binding affinities with EscrCSP8a and lower affinities with EbraCSP8. In addition, there were seven, two, and one EbraCSPs mainly expressed in pupae, larvae, and eggs, respectively, indicating possible developmental-related roles in . We screened out several olfactory-related possible CSP genes in and and simulated the binding model of CSPs with different compounds, providing a basis for explaining the niche differentiation of the two weevils.
臭椿根象甲（）和臭椿干象甲（）是亲缘关系密切的物种，它们单食性地以同一寄主植物臭椿（Mill）Swingle为食，但取食寄主树的不同部位。然而，它们如何选择寄主树不同部位的机制尚不清楚。由于化学感应系统在寄主定位和产卵中起重要作用，我们从这两种象甲不同发育阶段的转录组中筛选了候选化学感应蛋白基因。在本研究中，我们分别鉴定出了臭椿根象甲和臭椿干象甲的12个候选化学感应蛋白（CSPs），其中新鉴定出3个EscrCSPs和1个EbraCSPs。qRT-PCR结果表明，EscrCSP7/8a/9和EbraCSP7/8/9在成虫触角中显著表达，而EscrCSP8a和EbraCSP8的序列同一性较低，这表明它们可能对不同的气味分子结合做出反应。此外，EbraCSP6和EscrCSP6主要在触角和喙中表达，可能参与化学感受过程。寄主植物的9种挥发性化合物与EscrCSP8a和EbraCSP8的结合模拟表明，(1R)-(+)-α-蒎烯、(-)-β-石竹烯和β-榄香烯与EscrCSP8a的结合亲和力较高，与EbraCSP8的亲和力较低。此外，分别有7个、2个和1个EbraCSPs主要在蛹、幼虫和卵中表达，表明它们在臭椿干象甲中可能具有与发育相关的作用。我们在臭椿根象甲和臭椿干象甲中筛选出了几个与嗅觉相关的可能的CSP基因，并模拟了CSPs与不同化合物的结合模型，为解释这两种象甲的生态位分化提供了依据。
