Question

What is the primary function of Bt toxin in genetically modified crops like Bt Cotton?

• A. Enhancing nutrient content.
• B. Providing resistance to fungal infections.
• C. Acting as a natural insecticide.
• D. Increasing drought tolerance.

Hint:

Remember the name: \textbf{Bt} stands for {\textbf{B}acillus \textbf{t}huringiensis}. This bacterium produces a protein toxic to insects. So, Bt crops are insect-resistant. The 't' in Bt can remind you of 'toxin'.

Answer 1

The Correct Option is C

Step 1: Concept Overview:
The question concerns the main purpose of incorporating the Bt toxin gene into crops like cotton. Bt refers to {Bacillus thuringiensis}, a bacterium found in soil.
Step 2: Detailed Explanation:


{Bacillus thuringiensis} naturally produces Cry proteins, also known as Bt toxins.
These proteins are safe for humans, mammals, and most beneficial insects but are toxic to specific insect larvae, like the cotton bollworm.
When an insect larva ingests the Bt toxin, the alkaline environment in its gut activates the protoxin. The activated toxin binds to receptors in the gut, creating pores that cause cell lysis, gut paralysis, and ultimately, the insect's death.
Genetic engineering allows scientists to isolate the Cry gene (which codes for the toxin) and insert it into the genome of plants such as cotton, corn, and brinjal.
The resulting GM crop, like Bt Cotton, produces its own Bt toxin. When a susceptible insect pest feeds on the plant, it ingests the toxin and dies. Thus, the Bt toxin's main function is to provide the plant with resistance to certain insect pests, essentially acting as a natural insecticide.
Step 3: Conclusion:
The primary function of Bt toxin in GM crops is to serve as an inherent, natural insecticide, protecting the plant from specific insect pests.