Previous Year Question

Bt Cotton is a Genetically Modified Crop developed using genes obtained from the bacterium Bacillus thuringiensis (Bt). It is a Gram-Positive, spore-forming soil bacterium that produces insecticidal proteins effective against certain insect pests.

The cry genes found in Bacillus thuringiensis are responsible for producing specific insecticidal proteins. These genes are transferred into cotton plants through Genetic Engineering, enabling the plants to develop resistance against targeted insect pests.

Mechanism of Action of Bt Toxin: During spore formation, the bacterium produces inactive protein crystals. When susceptible insect larvae ingest these crystals, the proteins become activated in their Alkaline Gut. The activated toxin binds to specific receptors on the epithelial cells of the Midgut and forms pores in their membranes. This damages the cells and may eventually cause the death of the insect.

Bt Cotton was developed primarily to protect the crop against pests such as Bollworms. Proteins such as Cry1Ac and Cry2Ab have been used in Bt Cotton. Different Cry proteins are effective against different groups of insects.

Commercial cultivation of Bt Cotton was approved in India in 2002. It was the first genetically modified crop approved for commercial cultivation in India. The approval was granted by the Genetic Engineering Appraisal Committee (GEAC), constituted under the Environment (Protection) Act, 1986.

Bt Cotton primarily provides protection against targeted Bollworm pests. It is not equally effective against all insects, particularly Sucking Pests. Continuous use may also lead to the development of Resistance in insect populations, making Insect Resistance Management important.