Question

Transgenic plants developed by introducing Bt gene in crops like brinjal, maize, cotton etc. provide resistance to:

• A. insect pests
• B. viral infection
• C. heat
• D. fungal diseases

Hint:

Remember the source: {B}acillus {t}huringiensis. The name itself is a clue. It's a biological pesticide, and the gene provides resistance to {b}ugs (insects).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question asks about the specific trait conferred by the Bt gene when introduced into crops.
Step 2: Detailed Explanation:
The Bt gene is derived from the soil bacterium {Bacillus thuringiensis}.
This bacterium produces a protein crystal, known as Cry protein, during sporulation.
This Cry protein is an endotoxin that is specifically toxic to certain groups of insects (e.g., lepidopterans - bollworms, dipterans - flies/mosquitoes, coleopterans - beetles).
When an insect pest ingests the plant tissues containing the Bt toxin, the alkaline pH of its midgut solubilizes the crystals. The toxin is then activated by proteases in the insect gut, binds to receptors on the gut wall, and creates pores. This leads to cell lysis, gut paralysis, and ultimately the death of the insect.
Therefore, introducing the gene that codes for this protein into plants makes them genetically modified to be resistant to specific insect pests.
Step 3: Final Answer:
The Bt gene provides resistance against insect pests.