Abstract: 【Aim】 The objective of this study is to identify the odorant receptor gene from the Chinese honeybee, Apis cerana cerana, and to analyze its structure properties. Moreover, the expression profiles of this gene in different tissues and different developmental stages of A. c. cerana under the plentiful or scarce nectar and pollen source conditions were explored, so as to provide a fundamental evidence for the further study on the physiological function of this gene. 【Methods】 The cDNA sequence of the odorant receptor gene was amplified using RT-PCR from the antenna of A. c. cerana foragers, the deduced protein structure was predicted using different bioinformatics software, and the phylogenetic tree was constructed using neighbor-joining method of MEGA 6.0. The expression profiles of this gene in different tissues (antenna, head without antenna, thorax without wings, abdomen, legs and wings) of workers of different day-old (1, 5, 10, 15, 20, 25 and 30 day-old) under different nectar and pollen source conditions were detected by quantitative real-time PCR. 【Results】 The cDNA sequence of the odorant receptor gene AcerOR113 (GenBank accession no.: KT252877.1) was obtained from the antenna of A. c. cerana foragers. It contains a 1 035 bp open reading frame, encoding a putative protein of 344 amino acids with an estimated molecular weight of 40.13 kD and the theoretical pI of 7.05, no signal peptide, and with six transmembrane structure and N-terminal intracellularly located. A conserved 7tm-6 superfamily domain between 59-343 amino acid residues was identified. Amino acid sequence alignment and phylogenetic analysis showed that AcerOR113 has 94% amino acid sequence identity and the closest evolutionary relationship with AmelOR113 of A. mellifera. Real-time PCR data revealed that the expression level of AcerOR113 was extremely higher in the antenna than in other tissues (P<0.01) of workers of different day-old, and the lowest in the abdomen. In the antenna, the expression level of AcerOR113 under the plentiful nectar and pollen source condition was extremely significantly lower than that under the scarce nectar and pollen source condition (P<0.01). 【Conclusion】 AcerOR113 possesses the typical characteristics of insect odorant receptor, and its gene is highly expressed in the antenna of A. c. cerana adults with significantly higher expression level under the scarce nectar and pollen source condition than under the plentiful nectar and pollen source condition, suggesting that AcerOR113 may be involved in the identification of floral scents of nectar and pollen in the environment.

Key words: Apis cerana cerana, worker, odorant receptor, bioinformatics analysis, temporal-spatial expression, pollen and nectar source