Genes for Bt Toxins - The use of pesticides and insecticides is a common measure in plant protection programmes, since pests and insects cause appreciable damage to our crops. Most of these pesticides and insecticides are chemically synthesized.
However, an exception is the, Bt toxins produced by a bacterial species (Bacillus thuringiensis), so that a spore preparation of this bacterium has been used as a biological insecticide during the last 20 years.

Insecticidal activity of this species depends on a protein (delta endotoxins) synthesized during sporulation. Since these toxins are very specific in their action, they are safe insecticides, but their use is limited due to high production cost and due to instability of crystal proteins when exposed in the field.

When inheritance of insect resistance was studied using crosses with normal control plants, F_l showed resistance and F₂generation exhibited expected segregation, Field tests using transgenic insect resistant plants were also conducted and the results were excellent with tobacco and tomato.

In view of this, one can expect that transgenic crop plants for this trait may be released for commercial cultivation in the near future. There were also reports that India may acquire technology from USA for introducing Bt toxin gene in cotton for the development of resistance against pests in this major cash crop of India.