A Comparative Study of Transcriptional Regulation Mechanism of Cytochrome P450 CYP6B7 between Resistant and Susceptible Strains of Helicoverpa armigera

Cytochrome P450 CYP6B7 has previouslybeen provedto be associated with fenvalerate-resistance in Helicoverpaarmigera. Here, how CYP6B7 is regulatedand involved in the resistance of H. armigera isstudied. Seven base differences (M1-M7) were found in CYP6B7 promoter between a fenvalerate-resistant (HDTJFR)and a susceptible (HDTJ) strain of H. armigera. M1-M7sites in HDTJFR were mutated into the corresponding base in HDTJ,and pGL3-CYP6B7 reporter genes with different mutationsites were constructed. Fenvalerate-induced activities of reportergenes mutated at M3, M4, and M7 sites were significantly reduced.Transcription factors Ubx and Br, whose binding sites contain M3 andM7, respectively, were overexpressed in HDTJFR. Knockdown of Ubx and Br results in significant expressioninhibition of CYP6B7 and other resistance-relatedP450 genes, and increase of sensitivity of H. armigera to fenvalerate. These results indicate that Ubx and Br regulatethe expression of CYP6B7 to mediate the fenvalerate-resistancein H. armigera.