Education Ministry Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
Comp Biochem Physiol A Mol Integr Physiol. 2013 Jun;165(2):254-62. doi: 10.1016/j.cbpa.2013.03.016. Epub 2013 Mar 16.
Pheromone-binding proteins (PBPs), a sub-family of odorant-binding proteins, are thought primarily to bind and transport the sex pheromones in moths. Considering multiple components of sex pheromone and multiple PBP genes exist in a single species, PBPs may contribute to the discrimination of different sex pheromone components. However, so far this discrimination is still unclear. Our previous ligand-binding assays showed that Spodoptera litura PBP1 (SlitPBP1) did not exhibit an obvious binding specificity among different sex pheromone components. In this study, binding specificity of the other two PBPs in S. litura (SlitPBP2 and SlitPBP3) was further investigated. As a result, SlitPBP2 was capable of binding all four sex pheromone components with similar affinities; whereas SlitPBP3 showed very weak binding affinities to them except Z9,E12-14:Ac. Similar results were also obtained from studied pheromone analogs, to which SlitPBP2 showed much stronger affinities than SlitPBP3. However, both SlitPBP2 and SlitPBP3 exhibited overall weaker affinities to sex pheromones and their analogs than SlitPBP1. In addition, quantitative real time PCR showed that three SlitPBP genes exhibited a very different sex-biased expression in adult antenna with male-biased for SlitPBP1 and SlitPBP2 while female-biased for SlitPBP3. Finally, ligand-binding assays indicated that the two SlitPBPs showed a similar pH-dependent conformational change as reported SlitPBP1, but these three SlitPBPs showed different behavior across a pH range or something similar. Taken together, our data suggest that in S. litura PBP1 and PBP2 may play critical roles in the perception of female sex pheromones, but do not show an obvious discriminative ability among different sex pheromone components; whereas PBP3 may have other functions.
信息素结合蛋白(PBPs)是气味结合蛋白的一个亚家族,其主要作用被认为是结合和运输蛾类的性信息素。考虑到单一物种中存在多种性信息素成分和多个 PBP 基因,PBPs 可能有助于不同性信息素成分的区分。然而,到目前为止,这种区分仍然不清楚。我们之前的配体结合分析表明,斜纹夜蛾 PBP1(SlitPBP1)在不同性信息素成分之间没有表现出明显的结合特异性。在本研究中,进一步研究了斜纹夜蛾中另外两种 PBP(SlitPBP2 和 SlitPBP3)的结合特异性。结果表明,SlitPBP2 能够以相似的亲和力结合所有四种性信息素成分;而 SlitPBP3 除了 Z9,E12-14:Ac 之外,对它们的结合亲和力非常弱。类似的结果也在研究的信息素类似物中得到,SlitPBP2 对它们的亲和力比 SlitPBP3 强得多。然而,SlitPBP2 和 SlitPBP3 对性信息素及其类似物的总体亲和力均弱于 SlitPBP1。此外,实时定量 PCR 显示,三个 SlitPBP 基因在成年触角中表现出非常不同的性别偏倚表达,SlitPBP1 和 SlitPBP2 呈雄性偏倚,而 SlitPBP3 呈雌性偏倚。最后,配体结合分析表明,这两个 SlitPBPs 表现出与已报道的 SlitPBP1 相似的 pH 依赖性构象变化,但这三个 SlitPBPs 在 pH 范围内或类似情况下表现出不同的行为。综上所述,我们的数据表明,在斜纹夜蛾中,PBP1 和 PBP2 可能在雌性性信息素的感知中发挥关键作用,但在不同性信息素成分之间没有表现出明显的区分能力;而 PBP3 可能具有其他功能。