Which of the following is true about Bt Cotton ?

Both A and B.

a-B. thuringiensis forms protein crystals during a particular phase of their growth.

b-The activated toxin binds to the surface of midgut epithelial cells.

c-CryIIAb controls corn borer.

d-Both a and b is the correct option .

The proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms, that of cryIAb controls corn borer.

The Bt toxin protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect.