title: Two novel sodium channel mutations associated with resistance to indoxacarb and metaflumizone in the diamondback moth, Plutella xylostella.
abstract: Indoxacarb and metaflumizone belong to a relatively new class of sodium channel blocker insecticides (SCBIs). Due to intensive use of indoxacarb, field-evolved indoxacarb resistance has been reported in several lepidopteran pests, including the diamondback moth Plutella xylostella, a serious pest of cruciferous crops. In particular, the BY12 population of P. xylostella, collected from Baiyun, Guangdong Province of China in 2012, was 750-fold more resistant to indoxacarb and 70-fold more resistant to metaflumizone compared with the susceptible Roth strain. Comparison of complementary DNA sequences encoding the sodium channel genes of Roth and BY12 revealed two point mutations (F1845Y and V1848I) in the sixth segment of domain IV of the PxNav protein in the BY population. Both mutations are located within a highly conserved sequence region that is predicted to be involved in the binding sites of local anesthetics and SCBIs based on mammalian sodium channels. A significant correlation was observed among 10 field-collected populations between the mutant allele (Y1845 or I1848) frequencies (1.7% to 52.5%) and resistance levels to both indoxacarb (34- to 870-fold) and metaflumizone (1- to 70-fold). The two mutations were never found to co-exist in the same allele of PxNav , suggesting that they arose independently. This is the first time that sodium channel mutations have been associated with high levels of resistance to SCBIs. F1845Y and V1848I are molecular markers for resistance monitoring in the diamondback moth and possibly other insect pest species.
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Xing-Liang
authors: XL
authors: Wang
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Wen
authors: W
authors: Su
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Jian-Heng
authors: JH
authors: Zhang
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Yi-Hua
authors: YH
authors: Yang
authors: Department of Entomology, Genetics and Neuroscience Programs, Michigan State University, East Lansing, MI, USA.
authors: Ke
authors: K
authors: Dong
authors: College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
authors: Yi-Dong
authors: YD
authors: Wu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D007305:Insecticide Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects / Q000235:genetics*; D009154:Mutation; D010078:Oxazines / Q000494:pharmacology*; D012664:Semicarbazones / Q000494:pharmacology*; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000737:chemistry / Q000235:genetics*
chemical_list: D010078:Oxazines; D012664:Semicarbazones; D026941:Sodium Channel Blockers; D015222:Sodium Channels; C401104:indoxacarb; C528570:metaflumizone
keywords: Plutella xylostella; indoxacarb; metaflumizone; mutation; resistance; sodium channel