title: Constitutive overexpression of cytochrome P450 associated with imidacloprid resistance in Laodelphax striatellus (Fallén).
abstract: BACKGROUND
  Imidacloprid is a principal insecticide for controlling rice planthoppers worldwide. Resistance to imidacloprid has been reported in a field population of Laodelphax striatellus. The present work was conducted to study the molecular mechanisms of imidacloprid resistance.
  
  
  RESULTS
  An imidacloprid-resistant strain was produced by selecting a field population with imidacloprid for 24 generations. Piperonyl butoxide (PBO) showed a 1.70-fold synergistic effect. Enzyme activity assays were conducted, and cytochrome P450 monooxygenase showed 1.88-fold activity. The mRNA expression levels of 57 P450 genes were compared. Four CYP genes were found to be overexpressed and significantly different to the susceptible strain. Four strains were selected with imidacloprid for a short period, and the expression levels of ten identified detoxification genes were then compared. Only CYP353D1v2 overexpressed and was significantly different to the susceptible strain. Strong correlation was found between CYP353D1v2 expression levels and imidacloprid treatments. Additionally, gene-silencing RNAi via dsRNA feeding showed that depressing the expression of CYP353D1v2 could significantly enhance the sensitivity of L. striatellus to imidacloprid.
  
  
  CONCLUSIONS
  Constitutive overexpression of four CYP genes was associated with imidacloprid resistance in long-term selection, and expression of CYP353D1v2 with imidacloprid resistance in short-term selection in L. striatellus.
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Mohammed Esmail Abdalla
authors.initials: ME
authors.lastname: Elzaki
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Wanfang
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Ai
authors.initials: A
authors.lastname: Feng
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Qiou
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Wanxue
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Jiangsu/The Key Laboratory of Monitoring and Management of Plant Diseases and Insects, Ministry of Agriculture, Nanjing, 210095 Jiangsu, China.
authors.forename: Zhaojun
authors.initials: Z
authors.lastname: Han
mesh_terms: D000818:Animals; D002681:China; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D006430:Hemiptera / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology*; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000494:pharmacology*
chemical_list: D007093:Imidazoles; D019476:Insect Proteins; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid; D003577:Cytochrome P-450 Enzyme System
keywords: Laodelphax striatellus; RNA interference; constitutive overexpression; cytochrome P450; imidacloprid