Construction and characterisation of near-isogenic Plutella xylostella (Lepidoptera: Plutellidae) strains resistant to Cry1Ac toxin

Authors

  • Xun Zhu,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
    2. Laboratory of Pesticide, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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    • Dr. Xun Zhu, Dr. Yanyuan Lei and M. Yanjv Yang contributed equally to this article.
  • Yanyuan Lei,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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    • Dr. Xun Zhu, Dr. Yanyuan Lei and M. Yanjv Yang contributed equally to this article.
  • Yanjv Yang,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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    • Dr. Xun Zhu, Dr. Yanyuan Lei and M. Yanjv Yang contributed equally to this article.
  • Simon W Baxter,

    1. School of Molecular and Biomedical Science, University of Adelaide, SA, Australia
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  • Jianhong Li,

    1. Laboratory of Pesticide, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
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  • Qingjun Wu,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Shaoli Wang,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Wen Xie,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Zhaojiang Guo,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Wei Fu,

    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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  • Youjun Zhang

    Corresponding author
    1. Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
    • Correspondence to: Youjun Zhang, Department of Entomology, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie, Haidian District, Beijing 100081, China. E-mail: zhangyoujun@caas.cn

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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.

CONCLUSION

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

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