Abstract：
The chemosensory system plays an important role in the host plants location. Plagiodera versicolora (Coleoptera: Chrysomelidae) is a worldwide leaf-eating forest pest that feeds exclusively on salicaceous trees. There is no function study of odorant binding proteins (OBPs) in P. versicolora. In the current study, we found that PverOBP37 has a high expression in male and female antennae, heads, and legs by quantitative real-time PCR. The binding properties of PverOBP37 to 18 host plant volatiles were determined by fluorescence competition binding assays. The results showed that PverOBP37 could bind to the host plant volatile, o-cymene. Furthermore, four candidate key amino acid residues (F8, Y50, F103, and R107) of PverOBP37 to o-cymene were identified by molecular docking. The functional assay to confirm Y50, F103, and R107 mutations were key amino acid residues of PverOBP37 involved in the binding to o-cymene. Knockdown of PverOBP37 and Y-tube behavioral bioassays of mated females led to a significantly reduced attraction to o-cymene. This study not only revealed the molecular mechanism of PverOBP37 but also suggested that PverOBP37 is essential to detect host plant volatiles as cues to search for egg-laying sites in P. versicolora.
摘要：
化学感应系统在寄主植物的定位中起着重要作用。Plasgioderaversicolora（鞘翅目：Chrysomelidae）是一种世界性的食叶森林害虫，仅以水杨酸树为食。目前还没有对杂色假单胞菌气味结合蛋白(OBP)的功能进行研究。在目前的研究中,我们发现PverOBP37在男性和女性触角中高表达，头,和腿通过定量实时PCR。通过荧光竞争结合测定法确定PverOBP37与18种寄主植物挥发物的结合特性。结果表明,PverOBP37能与寄主植物挥发物结合,o-cymene.此外，通过分子对接鉴定了PverOBP37对邻甲基异丙基苯的四个候选关键氨基酸残基（F8，Y50，F103和R107）。确认Y50、F103和R107突变的功能测定是PverOBP37的关键氨基酸残基,其参与与邻-异丙基苯并甲苯的结合。击倒PverOBP37和交配雌性的Y管行为生物测定导致对o-cymene的吸引力显着降低。这项研究不仅揭示了PverOBP37的分子机制，而且还表明PverOBP37对于检测寄主植物挥发物是必不可少的，作为在P中寻找产卵位点的线索。
