When a susceptible insect ingests the inactive B t protoxin produced by a genetically modified crop, the protoxin is converted into an active form that eventually creates pores in the midgut epithelial cells. Which specific condition in the insect's alimentary canal is responsible for this activation?

Step-by-step solution

The B t toxin is produced as an inactive protoxin in the bacterium and the transgenic plant. Once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut, which solubilises the protein crystals. The activated toxin then binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis. Acidic pH, mechanical grinding, and foregut enzymes are not the triggers for solubilising the protoxin crystals. Answer: Alkaline pH of t