Correct Option
The insect-resistant cotton variety, commonly known as Bt cotton, was developed by incorporating a toxic gene from the bacterium Bacillus thuringiensis (Bt) into the cotton plant's genome. This gene codes for the production of specific Cry proteins. When ingested by target insect pests, such as bollworms, these proteins become active in the alkaline environment of the insect's gut, binding to receptor sites and causing the gut lining to rupture. This leads to the death of the insect, thereby conferring inherent pest resistance to the cotton plant.
Incorrect Options
Bacillus subtilis is a Gram-positive bacterium widely recognized for its beneficial applications in enzyme production, probiotics, and as a plant growth-promoting rhizobacterium. It is not associated with the production of insecticidal toxins for transgenic crops.
Bacillus amyloliquefaciens is known for its industrial applications, particularly in the production of enzymes like alpha-amylase and various antimicrobial compounds. It does not possess genes for insecticidal proteins relevant to pest-resistant crop development.
Bacillus globlii is not a recognized species in the context of insecticidal gene transfer for transgenic crops. It does not play a role in the development of pest-resistant varieties like Bt cotton.