title: A point mutation in the glutamate-gated chloride channel of Plutella xylostella is associated with resistance to abamectin.
abstract: The diamondback moth, Plutella xylostella, is a global pest of cruciferous vegetables. Abamectin resistance in a field population of P. xylostella was introgressed into the susceptible Roth strain. The resulting introgression strain Roth-Abm showed 11 000-fold resistance to abamectin compared with Roth. An A309V substitution at the N-terminus of the third transmembrane helix (M3) of the glutamate-gated chloride channel of P. xylostella (PxGluCl) was identified in Roth-Abm. The frequency of the V309 allele of PxGluCl was 94.7% in Roth-Abm, whereas no such allele was detected in Roth. A subpopulation of Roth-Abm was kept without abamectin selection for 20 generations to produce a revertant strain, Roth-Abm-D. Abamectin resistance in Roth-Abm-D declined to 1150-fold compared with Roth, with the V309 allele frequency decreased to 9.6%. After treatment of the Roth-Abm-D strain with 80 mg/l abamectin the V309 allele frequency in the survivors increased to 55%. This demonstrates that the A309V mutation in PxGluCl is strongly associated with a 10-fold increase in abamectin resistance in Roth-Abm relative to Roth-Abm-D. Homology modelling and automated ligand docking results suggest that the A309V substitution allosterically modifies the abamectin-binding site, as opposed to directly eliminating a key binding contact. Other resistance mechanisms to abamectin in Roth-Abm are discussed besides the A309V mutation of PxGluCl.
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.|Institute of Plant and Environment Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
authors.forename: R
authors.initials: R
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: S
authors.initials: S
authors.lastname: Wu
authors.affiliation: School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK.
authors.forename: A O
authors.initials: AO
authors.lastname: O'Reilly
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
mesh_terms: D000818:Animals; D018118:Chloride Channels / Q000235:genetics*; D007305:Insecticide Resistance / Q000187:drug effects / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology; D007559:Ivermectin / Q000031:analogs & derivatives / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000235:genetics; D009036:Moths / Q000187:drug effects / Q000235:genetics*; D017354:Point Mutation
chemical_list: D018118:Chloride Channels; D007306:Insecticides; C109777:glutamate-gated chloride channels; C048324:abamectin; D007559:Ivermectin
keywords: abamectin; glutamate-gated chloride channel; molecular docking; resistance; target site mutation