Question

The insecticidal protein in Bt cotton binds to the

• A. midgut epithelial cells
• B. midgut mesothelial cells
• C. foregut epithelial cells
• D. hindgut mesothelial cells

Answer 1

The correct option is A midgut epithelial cells

Bt cotton is a genetically modified plant with insect resistance. It contains the cry gene of the bacterium, Bacillus thuringiensis.

Bacillus thuringiensis forms crystalline proteins that are insecticidal (cry proteins). The endotoxin that accumulates in bacteria exist in inactive form (protoxin). It gets activated at an alkaline pH in the gut of the insects due to the solubilisation of the crystal proteins.

This active toxin generates pores in the epithelium of the midgut of the insects which results in the swelling of cells followed by lysis. This consequently results in the death of the insect.

Hence the correct option is
c. midgut epithelial cells