title: Functional analysis of a point mutation in the ryanodine receptor of Plutella xylostella (L.) associated with resistance to chlorantraniliprole.
abstract: BACKGROUND
  The diamondback moth, Plutella xylostella (L.) has developed extremely high resistance to chlorantraniliprole and other diamide insecticides in the field. A glycine to glutamic acid substitution (G4946E) in the P. xylostella ryanodine receptor (PxRyR) has been found in two resistant populations collected in Thailand and Philippines and was considered associated with the diamide insecticides resistance but no experimental evidence was provided. The present study aimed to clarify the function of the reported mutation in chlorantraniliprole resistance in P. xylostella.
  
  
  RESULTS
  We identified the same mutation (G4946E) in PxRyR from four field collected chlorantraniliprole resistant populations of Plutella xylostella in China. Most importantly, we found that the frequency of the G4946E mutation is significantly correlated to the chlorantraniliprole resistance ratios in P. xylostella (R(2)  = 0.82, P = 0.0003). Ligand binding assays showed that the binding affinities of the PxRyR to the chlorantraniliprole in three field resistant populations were 2.41-, 2.54- and 2.60-times lower than that in the susceptible one.
  
  
  CONCLUSIONS
  For the first time we experimentally proved that the G4946E mutation in PxRyR confers resistance to chlorantraniliprole in Plutella xylostella. These findings pave the way for the complete understanding of the mechanisms of diamide insecticides resistance in insects.
authors.affiliation: Department of Entomology, China Agricultural University, Beijing, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Guo
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Xuguo
authors.initials: X
authors.lastname: Zhou
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Li
authors.forename: Shangzhong
authors.initials: S
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Pei
authors.forename: Xiwu
authors.initials: X
authors.lastname: Gao
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology*; D009036:Moths / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D017354:Point Mutation / Q000235:genetics*; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics* / Q000378:metabolism; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
chemical_list: D007306:Insecticides; D019837:Ryanodine Receptor Calcium Release Channel; D062367:ortho-Aminobenzoates; C517733:chlorantranilipole
keywords: Plutella xylostella; chlorantraniliprole; insecticide resistance; point mutation; ryanodine receptor