Transcription factor aryl hydrocarbon receptor/aryl hydrocarbon receptor nuclear translocator is involved in regulation of the xenobiotic tolerance-related cytochrome P450 CYP6DA2 in Aphis gossypii Glover.

The cotton aphid, Aphis gossypii, is one of the most economically important agricultural pests worldwide as it is polyphagous and resistant to many classes of insecticides. Overexpression of the cytochrome P450 monooxygenase (P450) CYP6DA2 has previously been found to be associated with gossypol and spirotetramat tolerance in the cotton aphid. In the present study, the elements located in the promoter region (-357:-343; -250:-241; -113:-104) of CYP6DA2 were shown to control promoter activity, and gossypol induction was observed. We hypothesized that the expression of CYP6DA2 is subject to transcriptional regulation. To investigate the underlying mechanism, we assessed two transcription factors, aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (ARNT), and found that the abundance of AhR was highly correlated with CYP6DA2 abundance. RNA interference of AhR or ARNT significantly decreased the levels of the target gene as well as those of its counterpart, and both dramatically repressed CYP6DA2 expression. Cotransfection of the ARNT, AhR, or AhR plus ARNT and CYP6DA2 promoter constructs elevated CYP6DA2 promoter activity, with the AhR plus ARNT cotransfection being the most effective. Thus, these elements located in the promoter were responsible for CYP6DA2 transcription, and CYP6DA2 expression was regulated by the transcription factors AhR and ARNT.