The evolution of insect resistance to insecticides is frequently associated with overexpression of one or more cytochrome P450 enzyme genes.Although overexpression of CYP450 genes is a well-known mechanism of insecticide resistance, the underlying regulatory mechanisms are poorly understood.Here we uncovered the mechanisms of overexpression of the P450 gene, hobbit door for sale CYP321A8 in a major pest insect, Spodoptera exigua that is resistant to multiple insecticides.CYP321A8 confers resistance to organophosphate (chlorpyrifos) and pyrethroid (cypermethrin and deltamethrin) insecticides in this insect.Constitutive upregulation of transcription factors CncC/Maf are partially responsible for upregulated expression of CYP321A8 in the resistant strain.
Reporter gene assays and site-directed mutagenesis analyses demonstrated that CncC/Maf enhanced the expression read more of CYP321A8 by binding to specific sites in the promoter.Additional cis-regulatory elements resulting from a mutation in the CYP321A8 promoter in the resistant strain facilitates the binding of the orphan nuclear receptor, Knirps, and enhances the promoter activity.These results demonstrate that two independent mechanisms; overexpression of transcription factors and mutations in the promoter region resulting in a new cis-regulatory element that facilitates binding of the orphan nuclear receptor are involved in overexpression of CYP321A8 in insecticide-resistant S.exigua.