Abstract: 【Aim】 The objective of this study is to clone the coding region sequence of cytochrome CYP9E2 gene of the Chinese honeybee, Apis cerana cerana, and to analyze its expression profiles in workers, which will contribute to our understanding on the biological function of this gene. 【Methods】 Total RNAs were extracted from the dissected midgut tissues of A. cerana cerana foragers, and the coding sequence of CYP9E2 gene of A. cerana cerana was cloned using RT-PCR. The nucleotide and deduced amino acid sequences of the gene were analyzed using bioinformatics software. The relative expression levels of the gene in heads and midguts of the newly emerged workers, nurses, guarders and foragers were compared via quantitative real-time PCR (qRT-PCR). The relative expression levels of the gene between workers fed with flumethrin and the ones fed with 30% sucrose (control) were also compared. 【Results】The full length mRNA sequence of CYP9E2 gene of A. cerana cerana (named AcCYP9E2) is 1 600 bp (GenBank accession number: KX394629). Its coding region is 1 494 bp, which encodes 497 amino acids. The molecular weight and isoelectric point of the encoded protein are 57.026 kD and 8.32, respectively. The phylogenetic tree analysis showed that AcCYP9E2 of A. cerana cerana was firstly clustered with CYP9E2 genes from A. mellifera and A. florea. The qRT-PCR results showed that the relative expression level of AcCYP9E2 was different among the four worker bee groups, while the relative expression levels of AcCYP9E2 in the heads and midguts of foragers were both significantly higher than those of the newly emerged workers, nurses and guarders (P<0.05). The relative expression level of AcCYP9E2 was significantly higher in the midgut than that in the head in all the four worker bee groups (P<0.05), and the relative expression level of AcCYP9E2 in the midgut of the flumethrin-treated groups was significantly higher than that in the control group (P<0.05). 【Conclusion】 These results suggest that AcCYP9E2 may be involved in the metabolism process and detoxification of exogenous substances in the body of A. cerana cerana.

Key words:  Apis cerana cerana, worker bee, cytochrome P450, gene cloning, gene expression, detoxification enzyme