Bt toxin gene has been cloned from the bacteria, and has been expressed in plants, to provide resistance to insects (without the need for synthetic insecticide), Bt toxin gene forms protein crystals, These crystals contain a toxic insecticidal protein. Bt toxin protein exists as inactive protoxin in the host, but once the insect ingests the inactive toxin, it is converted into active form of toxin, due to alkaline pH of the gut which solubilises the crystals, causing death of the insect.
