Abstract:  【Aim】 This study aims to clone three pheromone binding protein (PBP) genes from the litchi fruit borer, Conopomorpha sinensis, and to analyze their sequences and expression characteristics, so as to provide essential basis for better use of sex pheromone for control. 【Methods】 The full-length cDNA of three PBP genes were cloned from the antennae of C. sinensis adults by transcriptome and RACE-PCR technique after extracting total RNA. The putative amino acid sequences were analyzed by bioinformatics software. The software I-TASSER was used to simulate 3D models, the software TM-align was used in protein homology modeling and the software COACH was used to speculate the binding sites. The expression profiles of the three genes in different developmental stages (larval and pupal stages), and different tissues of the 3 d-old female and male adults (antennae, head without antennae, thorax, abdomen, legs and wings) were analyzed by real-time PCR. 【Results】 Three PBP genes were cloned from the antennae of C. sinensis adults. They were named CsinPBP1, CsinPBP2 and CsinPBP3, and deposited under GenBank accession numbers MF093145, MF093146 and MF093147, respectively. Bioinformatic analysis revealed that the encoded proteins of the three genes have typical characteristics of odor binding proteins. Phylogenetic analysis revealed that CsinPBP1 has 72% amino acid sequence identity with PBP of Yponomeuta cagnagellus, CsinPBP2 has 55% amino acid sequence identity with PBP1 of Plutella xylostella, and CsinPBP3 has 39% amino acid sequence identity with PBP3 of Sesamia inferens. Software simulation analysis revealed that the 3D structures of CsinPBP1, CsinPBP2 and CsinPBP3 were the most similar with GOBP2 of Bombyx mori (PDB: 2wc6A), PBP1 of Amyetois transitetella (PDB: 4inxA) and PBP of B. mori (PDB: 2p70A), and were predicted to have 10, 7 and 8 binding sites, respectively. Expression profiling revealed that the three genes were only expressed in adult antennae, but neither in larval and pupal stages nor in other adult tissues including the head without antennae, thorax, abdomen, legs and wings. The relative expression levels of CsinPBP1, CsinPBP2 and CsinPBP3 in the antennae of male adults were 1.94, 28.19 and 32.94 times as high as those in the antennae of male adults, respectively. 【Conclusion】 Three PBP genes were cloned in C. sinensis. Their sequence and expression analysis suggest that they are related to sex pheromone sensing in males.

Key words: Conopomorpha sinensis, pheromone binding protein, gene cloning, sequence analysis, software simulation, expression profile