Abstract: 【Aim】 This study aims to clone two general odorant receptor genes, analyze their sequences and investigate their expression profiles in different tissues of adults of the cotton bollworm, Helicoverpa armigera. The findings will provide basic knowledge for further functional study of these two odorant receptor genes. 【Method】 We cloned the full-length cDNA sequences of two odorant receptor genes by PCR and RACE techniques. The structure prediction, sequence alignment and phylogenetic analysis of the coding products of these two odorant receptor genes were performed using different bioinformatics softwares. The expression profiles of these two genes in different tissues were investigated by using semi-quantitative RT-PCR. 【Results】 Two full-length cDNA sequences encoding odorant receptors were obtained and named as HarmOR9 and HarmOR29 (GenBank accession number KJ188252 and KJ188253, respectively). Sequence analysis showed that the full-length of HarmOR9 gene is 1 206 bp, which encodes a polypeptide of 401 amino acids, and the full-length of HarmOR29 gene is 1 188 bp, which encodes a polypeptide of 395 amino acids. Sequence alignment and phylogenetic analysis of the coding products of these two odorant receptor genes with reported odorant receptors from lepidopteran insects including Helicoverpa assulta, Bombyx mori, Heliothis virescens and H. armigera showed that the coding products of these two odorant receptor genes are obviously different from sex pheromone receptors, but cluster together with other general odorant receptors. The results of semi-quantitative PCR showed that these two odorant receptor genes were highly expressed in antennae with no significant difference between male and female, HarmOR29 was not expressed in other tissues, and HarmOR9 was slightly expressed in male labial palps but not in other tissues. 【Conclusion】 In this study, two odorant receptor genes were cloned in H. armigera. Sequence analysis showed that the coding products of these two genes own typical characteristics of odorant receptors and belong to general odorant receptors. The two odorant receptor genes were highly expressed in adult antennae, with no difference between male and female. Based on the findings, we infer that they may be involved in the identification of general odors.

Key words: Helicoverpa armigera, odorant receptor, gene cloning, tissue expression profile, semi-quantitative RT-PCR