title: Construction and characterisation of near-isogenic Plutella xylostella (Lepidoptera: Plutellidae) strains resistant to Cry1Ac toxin.
abstract: BACKGROUND
  Resistance to insecticidal Bacillus thuringiensis (Bt) toxins has arisen in multiple populations of the worldwide Brassica pest Plutella xylostella (L.). To help elucidate the mechanism of resistance to Bt Cry1Ac toxin in a population from Florida, two pairs of near-isogenic lines (NILs) were developed.
  
  
  RESULTS
  NILs were generated using either backcross or recombinant inbred line methodologies and evaluated for near-isogenicity with inter-simple-sequence-repeat (ISSR) markers. Backcross line BC6F4 maintained a similar level of Cry1Ac resistance to parental strain DBM1Ac-R (>5000-fold) yet showed 98.24% genetic similarity to the susceptible parental strain DBM1Ac-S. Single-pair backcrosses between DBM1Ac-S and BC6F4 revealed that Cry1Ac resistance was controlled by one recessive autosomal locus. BC6F4 exhibited high levels of cross-resistance to Cry1Ab and Cry1Ah but not to Cry1Ca or Cry1Ie.
  
  
  CONCLUSIONS
  Near-isogenic strains were constructed to provide a reliable biological system to investigate the mechanism of Cry1Ac resistance in P. xylostella. These data suggest that resistance to Cry1Ac, Cry1Ab and Cry1Ah is probably caused by the alteration of a common receptor not recognised by Cry1Ca or Cry1Ie. Understanding Bt toxin cross-resistance provides valuable information to consider when developing pest control strategies to delay resistance evolution. © 2014 Society of Chemical Industry.
authors.affiliation: Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China; Laboratory of Pesticide, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
authors.forename: Yanyuan
authors.initials: Y
authors.lastname: Lei
authors.forename: Yanjv
authors.initials: Y
authors.lastname: Yang
authors.forename: Simon W
authors.initials: SW
authors.lastname: Baxter
authors.forename: Jianhong
authors.initials: J
authors.lastname: Li
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Wu
authors.forename: Shaoli
authors.initials: S
authors.lastname: Wang
authors.forename: Wen
authors.initials: W
authors.lastname: Xie
authors.forename: Zhaojiang
authors.initials: Z
authors.lastname: Guo
authors.forename: Wei
authors.initials: W
authors.lastname: Fu
authors.forename: Youjun
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D061046:Biological Control Agents; D004731:Endotoxins / Q000494:pharmacology*; D005431:Florida; D006460:Hemolysin Proteins / Q000494:pharmacology*; D007178:Inbreeding; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology; D007814:Larva / Q000187:drug effects / Q000235:genetics; D009036:Moths / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D061046:Biological Control Agents; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Cry1Ac; Plutella xylostella; cross-resistance; inheritance; near-isogenic lines; resistance