Question

Why do lepidopterans die when they feed on Bt cotton pants? Explain how does it happen.

Answer 1

Some strains of Bacillus thuringiensis have a gene called cry gene that produces the protein that kills certain insects such as Lepidopterons (tobacco budworms, armyworm, beetles and flies). These genes are inserted in the Bt cotton plants that form protein crystal during a particular phase of their growth. These crystals contain a toxin insecticidal protein. When these proteins are ingested by the insect, they get activated and the toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis. The toxin is coded by a gene named cry.