The regulation of three new members of the cytochrome P450 CYP6 family and their promoters in the cotton aphid Aphis gossypii by plant allelochemicals.

Abstract

The expression of P450 genes in insects can be induced by plant allelochemicals. To understand the induction mechanisms, we measured the expression profiles of three P450 genes and their promoter activities under the induction of plant allelochemicals. The inducible expression of CYP6CY19 was the highest among three genes, followed by those of CYP6CY22 and CYP6DA1. The regions from -687 to +586 bp of CYP6DA1, from -666 to +140 bp of CYP6CY19 and from -530 to +218 bp of CYP6CY22 were essential for basal transcriptional activity. The cis-elements for plant allelochemicals induction were identified between -193 and +56 bp of CYP6DA1, between -157 and +140 bp of CYP6CY19 and between -108 and +218 bp of CYP6CY22. These promoter regions were found to contain a potential aryl hydrocarbon receptor element binding site with a conservative sequence motif 5'-C/TAC/ANCA/CA-3'. All these four plant allelochemicals were able to induce the expression of these P450 genes. Tannic acid had a better inductive effect than other three plant allelochemicals. Our study identified the plant allelochemical responsive cis-elements. This provides further research targets aimed at understanding the regulatory mechanisms of P450 genes expression and their interactions with plant allelochemicals in insect pests. © 2018 Society of Chemical Industry.