Cloning And Expression Analysis Of Odorant Receptor Genes Or57?Or139 And Or167 In The Chinese Honeybee,Apis Cerana Cerana

Apis cerana cerana was chosen as the research material in the study, then the AcerOr57?AcerOrl39 and AcerOr167 were researched on gene clone, sequence analysis and mRNA expression. The primary results were as follows:1 The cDNA sequence of the odorant receptor genes AcerOr57?AcerOr139 and AcerOr167 were cloned by PCR technique(GenBank accession number:KT716393, KT239370 and KT239369), containing the full open reading frame, respectively encoding 407?387 and 436 amino acid residues. It was predicted that the 3 proteins were hydrophobic protein, without signal peptide and glycosylation site. The structure of AcerOr57 and AcerOr139 were not stable, while it was stable of AcerOrl67. The transmenbrane domains of AcerOr139, AcerOr57 and AcerOr167 respectively included seven, six and five-transmenbrane domains, which were similar to the structural characteristics of the traditional odor receptors in insects.2 Using the Blastp in the NCBI database, homologous amino acid sequences of the three genes were searched. The result of alignment of amino acid sequences showed that the highest identity between AcerOr57 and AmelOr57 was 97%, and have higher similarity more than 69% with the AmelOr55? AmelOr56 and AmelOr58. It was infered that AcerOr55?AcerOr56?AcerOr57 and AcerOr58 may be the homologous genes produced by gene duplication in the process of evolution. The AcerOr139 shared high levels of identity with several odorant receptors of Apis mellifera. Among them, the identity between AcerOr139 and pseudogene AmelOr139 was the highest (73% identity), but the function of AcerOr139 needed further research. The identity between AcerOr167 and AmelOr167 was 94%, this result indicated that the two genes were orthologues.3 The relative expression of AcerOr57?AcerOr139 and AcerOr167 at different developmental stages (1,5,10,15,20,25 and 30 days after eclosion) and in different tissues (antennae, head (without antennae), thorax, abdomen, legs and wings) of the A. c. cerana were profiled by qRT-PCR. The results showed that the AcerOr57 and AcerOr167 transcripts were expressed in all tissues of workers, and the two genes were significantly higher in antennae than in other tissues (P<0.01). The AcerOrl39 transcript was expressed in all tissues of workers, but in different developmental stages, the expression characteristics were various in different tissues. The highest expression level of AcerOr139 in antennae was on the Id,5d,25d and 30d after eclosion, and which was on the 10d,15d and 20d in head. It was infered that the three genes was closely related with the olfactory function of A. c. cerana.The highest expression level of AcerOr57 was at the 1 day after eclosion in workers, the lowest was at the 10 day. Then the expression levels increased gradually. It was infered that the gene was closely related with collecting pollen and identifying the fragrance of flowers of A. c. cerana. The expression levels of AcerOrl39 were relatively high on the 5d,25d and 30d, The expression levels of AcerOrl67 were relatively high on the 5d and 20d. It was infered that two genes may play an important role in the identification process of the pollen and nectar in A. c. cerana. In addition, the expression levels of AcerOrl67 mRNA were significantly higher than that of AcerOr57 and AcerOrl39 in the entire developmental stages of worker. It was infered that AcerOr57 may play an important role in the olfactory system of A.c. cerana.