Give a brief account of Bt cotton.

The soil bacterium Bacillus thuringiensis is produces Cry (crystal) proteins are toxic to
insect larvae like tobacco bud worm, beetle etc.
* Cry proteins exist as inactive protoxins and get converted into active toxin due to the alkaline pH of the gut which solubilises the crystals.
* The activated toxin creates pores to the epithelial cells of midgut that case the death of the insect.
* Cry I Ac and Cry II Ab control the cotton bollworm.