title: Resistance to diamide insecticides in diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) is associated with a mutation in the membrane-spanning domain of the ryanodine receptor.
abstract: Diamide insecticides such as chlorantraniliprole and flubendiamide are a new class of insecticide that selectively target insect ryanodine receptors (RyR), a distinct class of homo-tetrameric calcium release channels which play a pivotal role in calcium homeostasis in numerous cell types. Resistance to these insecticides has recently been reported in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), a global lepidopteran pest of cruciferous crops. In the present study a region of the gene encoding the proposed diamide binding site of the RyR from P. xylostella collected from the Philippines and Thailand and found to be over 200-fold resistant to both chlorantraniliprole and flubendiamide compared to susceptible strains, were amplified by RT-PCR and sequenced. Comparison of the sequence with those from several susceptible reference strains revealed non-synonymous mutations in each of the resistant strains that in both cases lead to a glycine to glutamic acid substitution (G4946E) in the protein. The independent evolution of the same amino acid substitution within a highly conserved region of the proposed diamide binding site in two geographically separated resistant strains of P. xylostella strongly suggests a causal association with diamide resistance. Furthermore we designed a pyrosequencing-based diagnostic assay for resistance monitoring purposes that can be used to detect the G4946E mutation in field-collected samples of diamondback moth. The implications of the reported findings for resistance management strategies are discussed.
authors.affiliation: Department Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
authors.forename: Bartek
authors.initials: B
authors.lastname: Troczka
authors.forename: Christoph T
authors.initials: CT
authors.lastname: Zimmer
authors.forename: Jan
authors.initials: J
authors.lastname: Elias
authors.forename: Corinna
authors.initials: C
authors.lastname: Schorn
authors.forename: Chris
authors.initials: C
authors.lastname: Bass
authors.forename: T G Emyr
authors.initials: TG
authors.lastname: Davies
authors.forename: Linda M
authors.initials: LM
authors.lastname: Field
authors.forename: Martin S
authors.initials: MS
authors.lastname: Williamson
authors.forename: Russell
authors.initials: R
authors.lastname: Slater
authors.forename: Ralf
authors.initials: R
authors.lastname: Nauen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides; D007928:Lethal Dose 50; D008969:Molecular Sequence Data; D009036:Moths / Q000235:genetics*; D009154:Mutation; D017434:Protein Structure, Tertiary; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D007306:Insecticides; D019837:Ryanodine Receptor Calcium Release Channel