Abstract: Overexpression of cytochrome P450 CYP9A17v2 gene is involved in pyrethroid resistance in Helicoverpa armigera (Hübner). In order to study the mechanisms underlying regulation of CYP9A17v2, functional analysis of the promoter of CYP9A17v2 from H. armigera was performed in this study. Luciferase reporter plasmids containing serially truncated promoter fragments (-1 095-+43) of CYP9A17v2 were transiently transfected into Sf9 cells, and the promoter activity was measured with dual-luciferase reporter assay system. Functional analysis showed that all the seven deleted fragments had promoter activity, and a region between -197 and +43 exhibited the highest level of promoter activity. Transcription enhancer elements may exist in the region between -197 and -113 of CYP9A17v2 5′-regulation area, and transcription repressor elements may situate in the region between -1 095 and -197. This study would provide an important foundation for investigating transcriptional regulation mechanisms of CYP9A17v2 overexpression in H. armigera.

Key words: Helicoverpa armigera, cytochrome P450, CYP9A17v2, promoter, dual-luciferase reporter assay system, transcriptional regulation