绿盲蝽气味结合蛋白AlucOBP7的表达及气味结合特性

Expression and binding specificity analysis of odorant binding protein AlucOBP7 from Apolygus lucorum (Hemiptera:Miridae)

气味结合蛋白(odorant binding proteins,OBPs)在昆虫嗅觉识别中起着重要的作用,尤其是在运输外界脂溶性气味分子通过嗅觉感器淋巴液到达嗅觉受体(olfactory receptors,ORs)的过程中发挥关键作用。明确OBPs在昆虫同外界进行信息交流过程中的作用有利于阐明昆虫嗅觉识别的机制,同时可为利用干扰昆虫嗅觉识别来进行害虫防治奠定理论基础。本研究克隆了一个绿盲蝽Apolygus lucorum(Meyer-Dür)气味结合蛋白AlucOBP7基因(GenBank登录号:JQ675724),并进行了原核表达,以1-NPN为荧光探针采用荧光竞争结合实验研究了AlucOBP7蛋白和10种棉花挥发物及6种性信息素类似物的结合能力。结果表明:在10种棉花挥发物中,AlucOBP7能够和2-己酮及水杨酸甲酯有效结合,结合常数分别为55.13μmol/L和28.26μmol/L。在6种盲蝽性信息素类似物中,4-氧代-反-2-己烯醛和AlucOBP7具有较强的结合能力,结合常数为23.14μmol/L。丁酸乙酯、丁酸丁酯及己酸己酯也能够和AlucOBP7有效结合,但结合能力中等,结合常数分别为30.58,39.26和35.81μmol/L。初步推测,AlucOBP7可能是绿盲蝽性信息素结合蛋白(pheromone binding proteins,PBPs),并在感受性信息素和植物挥发物的过程中发挥双重功能。

Odorant binding proteins （OBPs） are widely involved in olfactory perception and play a key role in transporting hydrophobic odorants across the sensillum lymph to the olfactory receptors （ORs）. Understanding the roles of insect OBPs in chemical communication would help us elucidate the mechanism of insect olfaction perception and lay the theoretical basis for controlling the target pests by interfering with insect chemoreception. In this study, a novel OBP gene AlucOBP7 （GenBank accession no.： JQ675724） was identified from the green plant bug, Apolygus lucorum （Meyer-Dür）, and then the recombinant AlucOBP7 was prokaryotically expressed in Escherichia coli and purified. Fluorescence competitive binding assays were conducted to explore the binding properties of AlucOBP7 with 10 cotton volatiles and 6 sex pheromone analogs using a fluorescence probe, N-phenyl-1-naphthylamine （1-NPN）. The results revealed that for the 10 cotton volatiles, AlucOBP7 showed certain binding abilities with 2-hexanone and methylis salicylas, with the dissociation constants of 55.13 μmol/L and 28.26 μmol/L, respectively. For the 6 sex pheromone analogs, the AlucOBP7 had a strong binding affinity with 4-oxo-（E）-2-hexenal, with the dissociation constant of 23.14 μmol/L. Ethyl butyrate, butyl butanoate and hexyl hexanoate showed moderate binding abilities with AlucOBP7, and their dissociation constants were 30.58, 39.26 and 35.81 μmol/L, respectively. We so inferred that AlucOBP7 may be a pheromone binding protein of the green plant bug and play dual roles in the perception of sex pheromone and plant volatiles.