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

• Published in: Insect biochemistry and molecular biology 2012-11, Vol.42 (11), p.873-880
• Main Authors: Troczka, Bartek, Zimmer, Christoph T., Elias, Jan, Schorn, Corinna, Bass, Chris, Davies, T.G. Emyr, Field, Linda M., Williamson, Martin S., Slater, Russell, Nauen, Ralf
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Chlorantraniliprole; Flubendiamide; Insecticide Resistance - genetics; Insecticides; Lepidoptera; Lethal Dose 50; Molecular Sequence Data; Moths - genetics; Mutation; Plutella xylostella; Plutellidae; Protein Structure, Tertiary; Resistance; Ryanodine receptor; Ryanodine Receptor Calcium Release Channel - genetics; Sequence Analysis, DNA; Target-site mutation
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2012.09.001

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. [Display omitted] ► Cross-resistance to diamide insecticides in two strains of P. xylostella identified. ► A G4946E mutation in the ryanodine receptor is associated with diamide resistance. ► The same amino acid substitution evolves independently in two strains. ► The mutation is considered to be a new target-site resistance mechanism. ► A pyrosequencing diagnostic was developed to monitor resistant genotypes.