title: Identification of pyrethroid resistance associated mutations in the para sodium channel of the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae).
abstract: We investigated pyrethroid resistance mechanisms in Tetranychus urticae strains from Greece. Combined bioassay, biochemical and synergistic data indicated that although P450 mono-oxygenase activities were associated with the trait, target site insensitivity was the major resistance component. A 3.3 kb cDNA fragment of the T. urticae para sodium channel gene encompassing segment 4 of domain II to segment 6 of domain IV was obtained by a degenerate PCR strategy. The T. urticae sequence showed highest identity (56%) to the scabies mite, Sarcoptes scabiei, and was phylogenetically classified within the divergent group of Arachnida. Comparison of resistant and susceptible strains identified the point mutation F1538I in segment 6 of domain III, which is known to confer strong resistance to pyrethroids, along with a second mutation (A1215D) in the intracellular linker connecting domains II and III with an unknown role. Three transcripts were identified corresponding to the k and l alternative exons. The mode of inheritance of resistance was confirmed as incompletely recessive, which is consistent with a target site mechanism for pyrethroids.
authors.affiliation: National Agricultural Research Foundation (N.AG.RE.F.), Laboratory of Entomology and Agricultural Zoology, Plant Protection Institute of Heraklion, Heraklion, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Tsagkarakou
authors.forename: T
authors.initials: T
authors.lastname: Van Leeuwen
authors.forename: J
authors.initials: J
authors.lastname: Khajehali
authors.forename: A
authors.initials: A
authors.lastname: Ilias
authors.forename: M
authors.initials: M
authors.lastname: Grispou
authors.forename: M S
authors.initials: MS
authors.lastname: Williamson
authors.forename: L
authors.initials: L
authors.lastname: Tirry
authors.forename: J
authors.initials: J
authors.lastname: Vontas
mesh_terms: D017398:Alternative Splicing / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D005260:Female; D017344:Genes, Insect; D040582:Inheritance Patterns / Q000187:drug effects / Q000235:genetics; D007305:Insecticide Resistance / Q000187:drug effects* / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D063086:Organothiophosphates / Q000633:toxicity; D010802:Phylogeny; D010882:Piperonyl Butoxide / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015222:Sodium Channels / Q000737:chemistry / Q000235:genetics*; D016019:Survival Analysis; D040102:Tetranychidae / Q000187:drug effects* / Q000235:genetics*
chemical_list: D063086:Organothiophosphates; D011722:Pyrethrins; D012333:RNA, Messenger; D015222:Sodium Channels; C006863:butyl phosphorotrithioate; C099952:bifenthrin; D010882:Piperonyl Butoxide