Insects have evolved highly sensitive olfactory sensory systems to detect plant hosts and mates, with plant volatiles playing an important role in informing insect behavior. Chemosensory proteins (CSPs) are thought to play a key role in this process, but in this respect, there is limited information on brown planthopper Nilaparvata lugens, one of the most destructive pests of rice. To expand our understanding of CSP function in N. lugens we explored expression profiles and binding characteristics of NlugCSP3. The ligands with higher binding affinity were also validated by molecular docking and behavioral assays. NlugCSP3 mRNA was expressed at relatively higher levels in antennae and abdomen of 3-day-old unmated macropterous males as well as in antennae of 3-day mated macropterous and brachypterous females. Fluorescence competitive binding assays revealed that 5 out of 25 candidate volatiles are strong binders (Ki < 10 μM). Behavioral assays revealed that nonadecane and 2-tridecanone, which have high binding affinities in fluorescence competition-binding assays, displayed strong attractiveness to N. lugens. Pursuing this further, molecular docking analysis identified key amino acid residues involved in binding volatile compounds. Overall, our data provide a base for further investigation of the potential physiological functions of CSP3 in Nilaparvata lugens, and extend the function of NlugCSP3 in chemoreception of N. lugens.

中文翻译：

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化学发光蛋白3（Nilaparvata lugens（Hemiptera：Delphacidae））的表达谱和生化分析。

昆虫已经进化出高度敏感的嗅觉系统，可以检测植物宿主和伴侣，而植物挥发物在告知昆虫行为方面起着重要作用。化学感觉蛋白（CSP）被认为在此过程中起关键作用，但就此而言，关于稻飞虱（Nilaparvata lugens）（水稻最具破坏性的一种）的信息有限。为了扩大我们在CSP功能的了解褐飞虱我们探讨的表达谱和NlugCSP3结合的特点。具有较高结合亲和力的配体也通过分子对接和行为分析进行了验证。NlugCSP3在3天大的未交配的大翅类雄性的触角和腹部，以及在3天交配的大翅类和短毛雌性的触角中，mRNA的表达水平相对较高。荧光竞争结合测定表明25种候选挥发物中有5种是强结合剂（Ki <10μM）。行为测定表明，在荧光竞争结合测定中具有高结合亲和力的十九烷和2-癸烷酮显示出对N. lugens的强烈吸引力。进一步地，分子对接分析确定了结合挥发性化合物的关键氨基酸残基。总体而言，我们的数据为进一步研究褐飞虱中CSP3的潜在生理功能提供了基础，并扩展NlugCSP3在发光猪笼草的化学感受中的功能。