Bt toxin is produced by

Options

A. Bacillus mycoides
B. Bacillus thuringiensis
C. Bacillus licheniformis
D. Bacillus polymya

Answer

**Step-by-Step Solution:**

1. **Understanding BT Toxin**: BT toxin is a type of insecticidal protein that is produced by a specific bacterium. The term "BT" stands for "Bacillus thuringiensis," which is the organism responsible for producing this toxin.

2. **Identifying Bacillus thuringiensis**: Bacillus thuringiensis is a bacterium that produces proteins that are toxic to certain insects. These proteins are produced in the form of intracellular crystals within the bacterial cells.

3. **Mechanism of Action**: The BT toxin exists in an inactive form as these protein crystals. When ingested by insects, the alkaline pH in their gut activates the toxin, converting it into its active form, which then disrupts the insect's digestive system, leading to its death.

4. **Analyzing the Options**: The question provides four options regarding which Bacillus produces BT toxin:
- A) Bacillus mycoides
- B) Bacillus thuringiensis
- C) Bacillus licheniformis
- D) Bacillus polymyxa

5. **Determining the Correct Answer**: Among the options, Bacillus thuringiensis is the only bacterium known for producing BT toxin. The other three options (Bacillus mycoides, Bacillus licheniformis, and Bacillus polymyxa) do not produce this specific toxin.

6. **Conclusion**: Therefore, the correct answer to the question "BT toxin is produced by" is **Bacillus thuringiensis**.

**Final Answer**: Option B: Bacillus thuringiensis.

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