Insect Resistance


After herbicide tolerance, insect resistance is the second-most common trait in transgenic plants.

Insect resistance is a very common trait in genetically modified maize and cotton. Trasferred genes for Bt toxin are responsible for insect resistance among transgenic plants.

Genes for various forms of Bt toxin come from the soil bacterium Bacillus thuringiensis. Bt products have been used in biological pest management for about fifty years and are approved “chemicals” for organic farming.

Many laboratories around the world are actively using the Bt concept to give insect resistance to many valuable crops such as rice and apples.
Other transgenic strategies for conferring insect resistance are also under development:

  • Lectins are proteins produced by many plants (e.g. snowdrops) for defence against insect attack.   
  • Blocking digestive enzymes: some plants defend themselves by producing active agents that block the digestive enzymes used by their predators. Such defence proteins effectively starve herbivorous insects.

The genes encoding the defence proteins can be identified and transferred to plants. A large amount of effort goes into developing a transgenic line with dependable resistance.

See also:
Bt toxin
Bacillus thuringiensis (Bt)
Corn Borer
Refugia
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