Laboratory of Insect Toxicology, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou, People's Republic of China.
J Chem Ecol. 2014 Mar;40(3):267-75. doi: 10.1007/s10886-014-0406-4. Epub 2014 Mar 14.
Insects have evolved many physiological and behavioral adaptations to recognize external complex chemicals. Olfaction plays an important role in perceiving volatile chemicals, utilizing them to locate host sites, conspecifics, and enemies. Chemosensory proteins (CSPs) are present in high concentrations within the sensory sensilla of insects and are endowed with a heterogeneous range of functions. However, direct evidence for the involvement of CSPs in olfactory function is still lacking. In this study, a fluorescence-based ligand binding assay using Bdor-CSP2 illustrated its ability to bind the majority of the selected ligands of different shapes and chemical structures that are ecologically significant, host plant volatiles of Bactrocera dorsalis. RNAi-mediated silencing coupled with electrophysiological tests showed lower electrophysiological responses to (3Z)-hex-3-en-1-ol, trans-2-hexenal, 6-methylhept-5-en-2-one, and 3-methylbutyl acetate in dsBdor CSP2 treated flies compared with the untreated controls. The reduced expression of Bdor-CSP2 by RNA interference was confirmed by semi-quantitative PCR, real-time quantitative PCR and Western blot, which suggested the RNAi-treatment was responsible for the observed reduction of antennal responses in EAG recordings. These data suggest that the expression of Bdor-CSP2 is necessary for the recognition of antennal responses to some plant host volatiles by B. dorsalis.
昆虫已经进化出许多生理和行为适应性，以识别外部复杂的化学物质。嗅觉在感知挥发性化学物质方面起着重要作用，利用这些化学物质来定位宿主场所、同种生物和敌人。化感感受蛋白（CSPs）在昆虫的感觉感器中高度集中存在，并具有多种功能。然而，CSPs 参与嗅觉功能的直接证据仍然缺乏。在这项研究中，使用 Bdor-CSP2 进行的基于荧光的配体结合测定表明，它能够结合大多数具有不同形状和化学结构的选定配体，这些配体在生态上具有重要意义，是 Bactrocera dorsalis 的寄主植物挥发物。RNAi 介导的沉默结合电生理测试表明，与未处理的对照相比，dsBdor CSP2 处理的果蝇对（3Z）-己-3-烯-1-醇、反式-2-己烯醛、6-甲基庚-5-烯-2-酮和 3-甲基丁酸乙酯的电生理反应较低。半定量 PCR、实时定量 PCR 和 Western blot 证实了 Bdor-CSP2 的 RNA 干扰表达降低，这表明 RNAi 处理是导致 EAG 记录中触角反应减少的原因。这些数据表明，Bdor-CSP2 的表达对于 B. dorsalis 识别某些植物寄主挥发物的触角反应是必要的。
