title: Comparison of esterase gene amplification, gene expression and esterase activity in insecticide susceptible and resistant strains of the brown planthopper, Nilaparvata lugens (Stål).
abstract: Organophosphorus and carbamate insecticide resistance in Nilaparvata lugens is based on amplification of a carboxylesterase gene, Nl-EST1. An identical gene occurs in susceptible insects. Quantitative real-time PCR was used to demonstrate that Nl-EST1 is amplified 3-7-fold in the genome of resistant compared to susceptible planthoppers. Expression levels were similar to amplification levels, with 1-15-fold more Nl-EST1 mRNA in individual insects and 5-11-fold more Nl-EST1 mRNA in mass whole body homogenates of resistant females compared to susceptibles. These values corresponded to an 8-10-fold increase in esterase activity in the head and thorax of individual resistant insects. Although amplification, expression and activity levels of Nl-EST1 in resistant N. lugens were similar, the correlation between esterase activity and Nl-EST1 mRNA levels in resistant individuals was not linear.
authors: Cardiff School of Biosciences, Cardiff University, PO Box 915, Cardiff CF10 3TL, Wales, UK.
authors: J G
authors: JG
authors: Vontas
authors: G J
authors: GJ
authors: Small
authors: J
authors: J
authors: Hemingway
mesh_terms: D000818:Animals; D002219:Carbamates / Q000494:pharmacology*; D043182:Carboxylesterase; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000502:physiology*; D018076:DNA, Complementary; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D015870:Gene Expression; D006430:Hemiptera / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D009943:Organophosphorus Compounds; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D014404:Tubulin / Q000235:genetics
chemical_list: D002219:Carbamates; D018076:DNA, Complementary; D007306:Insecticides; D009943:Organophosphorus Compounds; D012333:RNA, Messenger; D014404:Tubulin; D002265:Carboxylic Ester Hydrolases; D043182:Carboxylesterase