Identification and characterization of both cis- and trans-regulators mediating fenvalerate-induced expression of CYP6B7 in Helicoverpa armigera.

As we known, inducibility is an important feature of P450 genes. Previous studies indicated that CYP6B7 could be induced and involved in fenvalerate detoxification in Helicoverpa armigera. However, the regulatory mechanism of CYP6B7 induced by fenvalerate is still unclear. In this study, CYP6B7 promoter of H. armigera was cloned and the cis-acting element of fenvalerate was identified to be located between -84 and - 55 bp of CYP6B7 promoter. Subsequently, 33 candidate transcription factors (CYP6B7-fenvalerate association proteins, CAPs) that may bind to the cis-acting element were screened and verified by yeast one-hybrid. Among them, the expression levels of several CAPs were significantly induced by fenvalerate. Knockdown of juvenile hormone-binding protein-like (JHBP), RNA polymerase II-associated protein 3 (RPAP3), fatty acid synthase-like (FAS) and peptidoglycan recognition protein LB-like (PGRP) resulted in significant expression inhibition of CYP6B7, and increased sensitivity of H. armigera to fenvalerate. Co-transfection of reporter gene p (-84/-55) with pFast-CAP showed that JHBP, RPAP3 and PGRP could significantly increase the activity of CYP6B7 promoter. These results suggested that trans-acting factors JHBP, RPAP3 and PGRP may bind with cis-acting elements to regulate the expression of CYP6B7 induced by fenvalerate, and play an important role in the detoxification of H. armigera to fenvalerate.