Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is…
Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to
Fungal diseases
Plant nematodes
Insect predators
Insect pests
Solution
Bt toxin is produced by Bacillus thuringiensis has been cloned in bacteria and been expressed in plants to provide resistance to insects without the need for insecticides in effect creating a biopesticide. Examples are Bt cotton, corn, rice, tomato, potato, soybean, etc. Specific Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into several crop plants such as cotton. The choice of a gene depends on the crop and the pest as most Bt toxins are insect group-specific. This toxin is encoded by a gene named cry. These genes are effective against various types of insects e.g., Lepidopterans (tobacco budworm, armyworm), Coleopterans (beetles), and dipterans (flies and mosquitoes). There are a number of such genes, for instance, the proteins encoded by gene cryIAc and cryIIAb controls cotton bollworm that of cryIAb corn borer.