Engineering Modified Bt Toxins to Counter Insect Resistance

@article{Sobern2007EngineeringMB,
  title={Engineering Modified Bt Toxins to Counter Insect Resistance},
  author={Mario Sober{\'o}n and Liliana Pardo-L{\'o}pez and I. L{\'o}pez and Isabel G{\'o}mez and Bruce E. Tabashnik and Alejandra Bravo},
  journal={Science},
  year={2007},
  volume={318},
  pages={1640 - 1642}
}
The evolution of insect resistance threatens the effectiveness of Bacillus thuringiensis (Bt) toxins that are widely used in sprays and transgenic crops. Resistance to Bt toxins in some insects is linked with mutations that disrupt a toxin-binding cadherin protein. We show that susceptibility to the Bt toxin Cry1Ab was reduced by cadherin gene silencing with RNA interference in Manduca sexta, confirming cadherin's role in Bt toxicity. Native Cry1A toxins required cadherin to form oligomers, but… 
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TLDR
It is discovered that resistance to Cry2Ab is associated with mutations disrupting the same ATP-binding cassette transporter gene (PgABCA2) in a laboratory-selected strain from Arizona, USA, and in field-selected populations from India, implying that mutations in the same gene confer Bt resistance in laboratory- and field- selected strains.
Asymmetrical cross-resistance between Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in pink bollworm
TLDR
It is shown that laboratory selection of pink bollworm with Cry2Ab caused up to 420-fold cross-resistance to Cry1Ac as well as 240-fold resistance to Cry2 Ab, indicating that cross-Resistance occurs between Cry1 Ac andCry2Ab in some key cotton pests.
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