Bacillus thuringiensis : An Environment Friendly Microbial Control Agent

摘要

Bacillus thuringiensis (Bt) is an aerobic, gram positive, spore forming soil bacterium that produces different kinds of crystal inclusions during sporulation. These crystal inclusions are composed of one or more crystal (Cry) and cytolytic (Cyt) toxins which are also called δ-endotoxins or insecticidal crystal proteins. Some of these proteins are highly toxic to certain insects but they are harmless to most other organisms including vertebrates and beneficial insects. Since their insecticidal potential has been discovered, it has been produced commercially and accepted as a source of environment friendly biopesticide all over the world. In the present era of transgenic technology, insecticidal toxins of Bacillus thuringiensis (Bt) assume considerable significance in the production of insect resistant crops such as cotton, maize, potato, rice etc. This review describes about biology of Bt toxin, recent progress in the development of Bt technology, evolution of resistant insect populations against Bt and management strategy.