Abstract: 【Aim】 Olfactory receptors (ORs) interact with the co-receptor (Orco) to form heterodimeric complexes that are critical for insect olfaction. Due to its highly conserved sequence, Orco has received extensive attention. The present study aims to clone and identify the Orco gene in Campoletis chlorideae, and analyze its tissue expression profiles. 【Methods】 The Orco gene from C. chlorideae was cloned by RT-PCR and transcriptome technology, and the putative amino acid sequence was analyzed by bioinformatics methods. The expression level of Orco in different tissues of C. chlorideae adults was analyzed by realtime quantitative PCR. 【Results】 The full-length cDNA sequence of Orco was obtained from C. chlorideae, and named as CchlOrco (GenBank accession no. KP255444). Sequence analysis revealed that the open reading frame of CchlOrco is 1 437 bp in length, encoding 478 amino acid residues with seven transmembrane domains. Real-time quantitative PCR results indicated that CchlOrco was mainly expressed in the adult antennae of C. chlorideae, while expressed in other tissues at an extremely low level. The expression level of CchlOrco in the antennae of male adults was 8.0-fold as high as that in the antennae of female adults. 【Conclusion】 The cloning of the full-length olfactory receptor gene CchlOrco and its expression profiles provide a basis for future functional study of CchlOrco and other olfactory receptor genes of C. chlorideae.

Key words: Campoletis chlorideae, olfactory receptor, gene cloning, tissue-specific expression, real-time quantitative PCR