B. thuringiensis forms protein crystals during a particular phase of their growth. The toxin is coded by a gene named cry. There are a number of them. Which is not an example of such plants ?

Options

A. cryIAc
B. Cry II Ab
C. sry
D. cryIAb

Answer

To solve the question regarding which option is not an example of a plant associated with the Bacillus thuringiensis (B. thuringiensis) protein crystals, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: B. thuringiensis is a bacterium that produces protein crystals containing insecticidal toxins, which are coded by genes known as cry genes. These proteins are effective against various insect pests.

2. **Identify the Options**: The options provided are:
- Cry1ac
- Cry2ab
- SRY
- Cry1ab

3. **Analyze Each Option**:
- **Cry1ac**: This gene codes for a protein that is effective against the tobacco budworm. Therefore, it is related to a plant (tobacco).
- **Cry2ab**: This gene is known to be effective against the cotton bollworm, indicating its association with cotton plants.
- **Cry1ab**: This gene is effective against the corn borer, linking it to corn plants.
- **SRY**: This does not correspond to any known cry gene associated with B. thuringiensis and is not related to the production of insecticidal proteins.

4. **Determine the Correct Answer**: Since SRY is not a cry gene and does not relate to any plant associated with B. thuringiensis, it is the correct answer to the question.

5. **Conclusion**: The option that is not an example of a plant associated with B. thuringiensis is **SRY**.

### Final Answer:
**SRY** is not an example of a plant associated with B. thuringiensis.

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