title: Identification of an alternative knockdown resistance (kdr)-like mutation, M918L, and a novel mutation, V1010A, in the Thrips tabaci voltage-gated sodium channel gene.
abstract: BACKGROUND
  Knockdown resistance (kdr) has been identified as a main mechanism against pyrethroid insecticides in many arthropod pests including in the onion thrips, Thrips tabaci. To characterize and identify pyrethroid-resistance in onion thrips in Washington state, we conducted insecticide bioassays and sequenced a region of the voltage gated sodium channel gene from several different T. tabaci populations.
  
  
  RESULTS
  Field collected Thrips tabaci were found to have large variations in resistance to the pyrethroid insecticide lambda-cyhalothrin. We identified two single nucleotide substitutions in our analysis of a partial sequence of the T. tabaci voltage-gated sodium channel gene. One mutation resulted in the non-synonymous substitution of methionine with leucine (M918L), which is well known to be responsible for super knockdown resistance in some pest species. Another non-synonymous substitution, a valine (GTT) to alanine (GCT) replacement at amino acid 1010 (V1010A) was identified in our study and was associated with lambda-cyhalothrin resistance.
  
  
  CONCLUSIONS
  We have characterized a known kdr mutation and identified a novel mutation in the voltage-gated sodium channel gene of Thrips tabaci associated with resistance to lambda-cyhalothrin. This gene region and these mutations are expected to be useful in the development of a diagnostic test to detect kdr resistance in many onion thrips populations.
authors: College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P.R. China; Department of Entomology, Washington State University, Pullman, WA, USA.
authors: Meixiang
authors: M
authors: Wu
authors: Hiroki
authors: H
authors: Gotoh
authors: Timothy
authors: T
authors: Waters
authors: Douglas B
authors: DB
authors: Walsh
authors: Laura Corley
authors: LC
authors: Lavine
mesh_terms: D055785:Gene Knockdown Techniques; D007305:Insecticide Resistance / Q000235:genetics*; D009154:Mutation; D009570:Nitriles / Q000633:toxicity*; D011722:Pyrethrins / Q000633:toxicity*; D015222:Sodium Channels / Q000235:genetics; D061149:Thysanoptera / Q000187:drug effects* / Q000235:genetics*; D014861:Washington
chemical_list: D009570:Nitriles; D011722:Pyrethrins; D015222:Sodium Channels; C037304:cyhalothrin
keywords: Thrips tabaci; kdr; point mutation; pyrethroid resistance; sodium channel