Pest Management Science (2015) 71, 225-233

Xun Zhu, Yanyuan Lei, Yanjv Yang, Simon W. Baxter, Jianhong Li, Qingjun Wu, Shaoli Wang, Wen Xie, Zhaojiang Guo, Wei Fu and Youjun Zhang (2015)
Construction and characterisation of near-isogenic Plutella xylostella (Lepidoptera: Plutellidae) strains resistant to Cry1Ac toxin
Pest Management Science 71 (2), 225-233
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.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Shaoli Wang, Qing Jun Wu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plutella xylostella
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Plutella xylostella