Abstract: 【Aim】 This study aims to study the function and ligand binding characteristics of pheromone binding proteins (PBPs) in the olfactory system of the yellow peach moth, Conogethes punctiferalis (Guenée). 【Methods】 A cDNA encoding pheromone binding protein of C. punctiferalis was cloned by RT-PCR and RACE. The expression pattern of the PBP gene in different sexes and developmental stages of C. punctiferalis was analyzed by real-time PCR, and the protein binding affinity was analyzed using fluorescence competitive binding assay. 【Results】 A novel PBP cDNA was obtained from C. punctiferalis and named as CpunPBP 1 (GenBank accession no. KP027486). Its open reading frame is 510 bp in length, encoding a protein of 169 amino acids with the predicted molecular weight of 19.12 kDa and theisoelectric point of 5.09. The 30 amino residues at the N-terminal hydrophobic region display the characteristics of a signal peptide. Protein signature analysis revealed that Cpun-PBP 1 shares the typical structural features of odorant binding proteins with other insects, including six conservative cysteine residues. Real-time quantitative PCR results indicated that CpunPBP1 was dominantly expressed in adult antennae, whereas scarcely expressed in egg stage and not expressed in larval and pupal stages. In addition, the recombinant protein of CpunPBP1 was prokaryotically expressed in Escherichia coli and purified. The binding affinity of CpunPBP1 to two sex pheromones and 14 plant volatiles showed that CpunPBP1 had a strong capability of binding two pheromone odorants (cis-10-hexadecenal and hexadecanoyl), with the binding constants of 7.32 and 9.39 μmol/L, respectively. Especially, CpunPBP1 could also bind with 8 plant volatiles, with the highest binding specificity to camphene (the binding constant: 3.76 μmol/L). 【Conclusion】 Based on these results, we inferred that CpunPBP1 play important roles in the process of discriminating odorants of pheromones and host plant volatiles of C. punctiferalis.

Key words: Conogethes punctiferalis, pheromone binding protein (PBP), gene cloning, expression pattern analysis, prokaryotic expression, fluorescence competitive binding assay