Abstract: 【Aim】 This study aims to clone an odorant receptor gene, AlucOR40, from Apolygus lucorum, to characterize its expression profiles in different tissues and to explore its function, so as to provide a theoretical basis for understanding the mechanisms of odor reception in A. lucorum. 【Methods】 The antennal transcriptome sequencing and RT-PCR amplification was used to clone the full-length cDNA of AlucOR40. The relative expression levels of this gene in different tissues of male and female adults of A. lucorum were detected using semi-quantitative RT-PCR. Through the combination of heterologous expression in Xenopus oocytes and two-electrode voltage clamp electrophysiological recording technique, the response of this odorant receptor to 60 odorants including sex pheromone of A. lucorum and plant volatiles was determined. The EAG responses of the 3-d-old adults of A. lucorum to the odorant ligand of AlucOR40 were further measured. 【Results】 AlucOR40 (GenBank accession number: KU886190) was cloned. AlucOR40 encodes 398 amino acids and the deduced protein has 7 transmembrane domains with an intracellular N-terminus and an extracellular C-terminus, which conforms to the typical structure of insect odorant receptors. The results of semi-quantitative RT-PCR showed that AlucOR40 was specifically expressed in the antenna of adults and the expression level was obviously higher in males than females. Two-electrode voltage clamp electrophysiological recording showed that AlucOR40 specifically responded to (E)-2-hexenol among the tested odorants. The EAG experiments showed that the 3-d-old adults had EAG response to (E)-2-hexenol, but the responses of males were significantly higher than those of females. 【Conclusion】 Our results suggest that the AlucOR40 is involved in identification of (E)-2-hexenol and may play an important role in identification of female by male during mating process.

Key words: Apolygus lucorum, odorant receptor, semi-quantitative RT-PCR, two-electrode voltage clamp, electroantennography