The protein toxin producing bacteria, used to control biological pest, is

Options

A. E. coli
B. Agrobacterium
C. Mycobacterium sp.
D. B. thuringiensis

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a specific type of bacteria that produces a protein toxin used to control biological pests.

2. **Identifying Biological Pests**: Biological pests are living organisms, often insects, that damage crops. Examples include bugs, moths, and fleas.

3. **Role of Biotechnology**: Biotechnology has been utilized to create genetically modified organisms (GMOs) that are resistant to these pests. One notable example is Bt cotton.

4. **Identifying the Bacteria**: The bacteria responsible for producing the toxin used in Bt cotton is **Bacillus thuringiensis** (Bt). This bacterium produces a toxin known as Bt toxin.

5. **Mechanism of Action**: The Bt toxin is initially inactive when produced by the bacteria. When the gene for this toxin is inserted into the cotton plant's genome, the plant can produce the toxin itself.

6. **Effect on Pests**: When pests feed on the Bt cotton, they ingest the Bt toxin. This toxin becomes active in the gut of the insect, leading to cell damage and ultimately the death of the insect.

7. **Conclusion**: Therefore, the correct answer to the question is **Bacillus thuringiensis**.

**Final Answer**: The protein toxin producing bacteria used to control biological pests is **Bacillus thuringiensis**.

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