title: Transcription factor cap n collar C regulates multiple cytochrome P450 genes conferring adaptation to potato plant allelochemicals and resistance to imidacloprid in Leptinotarsa decemlineata (Say).
abstract: Colorado potato beetle (CPB), Leptinotarsa decemlineata is a notorious pest of potato. Co-evolution with Solanaceae plants containing high levels of toxins (glycoalkaloids) helped this insect to develop an efficient detoxification system and resist almost every chemical insecticide introduced for its control. Even though the cross-resistance between plant allelochemicals and insecticides is well acknowledged, the underlying molecular mechanisms are not understood. Here, we investigated the molecular mechanisms involved in detoxification of potato plant allelochemicals and imidacloprid resistance in the field-collected CPB. Our results showed that the imidacloprid-resistant beetles employ metabolic detoxification of both potato plant allelochemicals and imidacloprid by upregulation of common cytochrome P450 genes. RNAi aided knockdown identified four cytochromes P450 genes (CYP6BJa/b, CYP6BJ1v1, CYP9Z25, and CYP9Z29) that are required for defense against both natural and synthetic chemicals. These P450 genes are regulated by the xenobiotic transcription factors Cap n Collar C, CncC and muscle aponeurosis fibromatosis, Maf. Studies on the CYP9Z25 promoter using the luciferase reporter assay identified two binding sites (i.e. GCAGAAT and GTACTGA) for CncC and Maf. Overall, these data showed that CPB employs the metabolic resistance mediated through xenobiotic transcription factors CncC and Maf to regulate multiple P450 genes and detoxify both imidacloprid and potato plant allelochemicals.
authors.affiliation: Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
authors.forename: Megha
authors.initials: M
authors.lastname: Kalsi
authors.affiliation: Department of Entomology, University of Kentucky, Lexington, KY 40546, USA. Electronic address: rpalli@email.uky.edu.
authors.forename: Subba Reddy
authors.initials: SR
authors.lastname: Palli
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D000818:Animals; D002460:Cell Line; D001517:Coleoptera / Q000235:genetics / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D007093:Imidazoles; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D007305:Insecticide Resistance / Q000235:genetics; D000073943:Neonicotinoids; D009574:Nitro Compounds; D051256:Oncogene Protein v-maf / Q000378:metabolism; D010675:Pheromones; D010936:Plant Extracts; D011401:Promoter Regions, Genetic; D011198:Solanum tuberosum / Q000737:chemistry
chemical_list: D007093:Imidazoles; D019476:Insect Proteins; D000073943:Neonicotinoids; D009574:Nitro Compounds; D051256:Oncogene Protein v-maf; D010675:Pheromones; D010936:Plant Extracts; C082359:imidacloprid; D003577:Cytochrome P-450 Enzyme System
keywords: Colorado potato beetle; Detoxification; Insecticide; Metabolic resistance; Resistance