Identification and expression analysis of NADH-cytochrome b5 reductase gene in the cotton bollworm, Helicoverpa armigera

NADH-cytochrome b5 reductase (CBR) is one of the most important components of cytochrome P450s, which play an essential role in the detoxification of xenobiotics as well as insecticide resistance in insect pest. In the present study, two novel full-length cDNAs of CBR of the cotton bollworm, Helicoverpa armigera (Hübner) were amplified by means of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) techniques. The sequencing results showed that the transcripts were 1809 bp and 1518 bp for HaCBR1 and HaCBR2, respectively, including 969 bp and 939 bp of complete open reading frame (ORF), which encoded 322 and 312 amino acids respectively. The putative structure and function of HaCBR1 and HaCBR2 were preliminarily analyzed by SMART program.HaCBR1 and HaCBR2 (GenBank accession numbers: HQ638220 and HQ190046) showed high identities with CBRs of other species. The expression of HaCBR1 and HaCBR2 mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR) in most developmental stages of H. armigera with the exception of eggs, as well as in tissues such as cuticle, fatbody and midgut. The expression level of the two genes was significantly induced by phenobarbital (PB). These results would contribute to the understanding of CBR function in H. armigera and provide information for further study on the interactions of different components of cytochrome P450 enzyme systems.

► Two different CBR genes were firstly cloned from H. armigera.
► Bio-information of both CBR genes was analyzed.
► Expression level of both CBR genes in different tissues was detected.
► Expression level of both CBR genes in different growth stages was detected.
► The change of expression level of both CBR genes induced by PB was examined.