绿盲蝽气味结合蛋白AlucOBP8的结合特性分析

气味结合蛋白(odorant binding proteins,OBPs)是参与昆虫嗅觉感知过程的一类重要蛋白,其功能之一是结合运输外界气味分子通过淋巴液到达神经元树突。本文克隆了一个绿盲蝽Apolygus lucorum(Meyer-Dür)气味结合蛋白AlucOBP8(GenBank登录号JQ675725)并进行了原核重组表达。组织表达谱分析表明,AlucOBP8基因主要在雌雄成虫触角表达。采用荧光竞争结合试验,研究了重组蛋白AlucOBP8与7种性信息素类似物和33种植物挥发物的结合能力。结果显示,7种性信息素类似物均不能与AlucOBP8有效结合,而植物挥发物中只有葎草烯(α-caryophyllene)和十二醛(dodecyl aldehyde)与AlucOBP8表现出较强的结合,结合常数分别为8.74和9.99 μmol/L。绿盲蝽雌雄成虫对这两种化合物的趋向结果表明,十二醛对绿盲蝽雄成虫具有显著的驱避作用。初步推断AlucOBP8为普通气味结合蛋白并参与寄主普通挥发气味的识别过程。

Binding Specificity Analysis of Odorant Binding Protein AlucOBP8 of Apolygus lucorum (Meyer-Dür)

Odorant binding proteins (OBPs), an important class of proteins, are involved in the process of insect olfactory perception. One of OBP’s functions is to bind and transport odor molecules through the lymph to reach neuronal dendrites. In the present study, we cloned an OBP gene of Apolygus lucorum (Meyer-Dür) (GenBank No.JQ675725) and named AlucOBP8. The quantitative real-time PCR (qRT-PCR) analysis demonstrated that the AlucOBP8 was mainly expressed in the antennae of both male and female adult bugs. The fluorescence competitive binding assays were conducted to measure the binding abilities of recombinant AlucOBP8 to seven sex pheromone analogs and thirty-three plant volatiles. The results revealed that AlucOBP8 could not bind to sex pheromone analogs. Only two plant volatiles, α-caryophyllene and dodecyl aldehyde showed strong binding affinities and the dissociation constant were 8.74 and 9.99 μmol/L, respectively. We measured the taxis selection of A. lucorum to α-caryophyllene and dodecyl aldehyde by using Y tube olfactometer. The results showed that dodecyl aldehyde had significantly repellent action on A. lucorum adult males. We suspected that the AlucOBP8 might be a general odorant binding protein to play roles in odor recognition of host plant volatiles.