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气味结合蛋白(odorant binding proteins,OBPs)在昆虫对寄主气味的感受中起重要作用,但有关Minus-C OBP及其功能的报道很少。本研究通过基因组数据分析并利用RACE技术,克隆和鉴定了二化螟Chilo suppressalis(Walker)的一个Minus-C OBP基因,命名为CsupOBP1(GenBank登录号:KC492498)。CsupOBP1基因的开放阅读框长423 bp,编码141个氨基酸,其中N端的18个氨基酸为预测的信号肽序列,成熟蛋白序列中具有4个保守的半胱氨酸位点。实时定量PCR分析显示,该基因在幼虫头部及成虫雌雄足、翅和雄性触角等化感组织中高表达,其中在雄虫触角内的表达量显著高于雌虫触角。利用荧光竞争结合实验对CsupOBP1重组蛋白与38种化合物的结合特性的测定表明,重组CsupOBP1与β-紫罗兰酮的结合能力最强(Ki=9.53μmol/L)。触角电位测定表明,二化螟成虫可对β-紫罗兰酮产生显著的触角电生理反应,但雄虫反应明显强于雌虫,与结合试验及雄虫触角中CsupOBP1的表达量显著高于雌虫触角的测定结果相一致。鉴于β-紫罗兰酮是水稻等植物中普遍存在的一种芳香气味组分,推测CsupOBP1可能通过对该气味的结合和运输,从而在二化螟对寄主植物的嗅觉定向中起作用。
Odorant binding proteins (OBPs) play an important role in insect’s perception of host odor, but few reports on Minus-C OBP and its function. In this study, a Minus-C OBP gene of Chilo suppressalis (Walker) was cloned and identified by Genome Data Analysis and RACE technology and named as CsupOBP1 (GenBank accession number: KC492498). The open reading frame of CsupOBP1 gene is 423 bp in length and encodes 141 amino acids, of which 18 amino acids at the N terminal end are the predicted signal peptide sequences and 4 conserved cysteine residues in the mature protein sequence. Real-time quantitative PCR analysis showed that the gene was highly expressed in sensory tissues such as male and female feet, wings and male antennae of larvae, and the expression level in male antennae was significantly higher than that of female antennae. The binding characteristics of CsupOBP1 recombinant protein to 38 compounds were demonstrated by fluorescence competition binding assay. The binding ability of recombinant CsupOBP1 to β-ionone was the strongest (Ki = 9.53μmol / L). Antennal potentials showed that adult adults of Sesamia inferens could produce significant electrophysiological responses to β-ionone, but the male responses were significantly stronger than those of females. The binding assay and the expression of CsupOBP1 in male antennae were significantly higher than those in females Determination of antennae consistent. Since β-ionone is a common aromatic component in plants such as rice, it is speculated that CsupOBP1 may play a role in the olfactory orientation of the stem borer to host plants by binding and transporting the odor.