Which of the following statement is not correct for Viroids?

Options

A. Causes potato spindle tuber disease and tobacco mosalic disease
B. In 1971, TO. Diener discovered these agents
C. Viroid was found to be a free RNA, it lacked the protein coat
D. RNA of viroid was of low molecular weight

Answer

To determine which statement is not correct for viroids, we need to analyze the characteristics of viroids based on the information provided.

### Step-by-Step Solution:

1. **Understanding Viroids**:
- Viroids are a type of pathogen that primarily infects plants. They are distinct from viruses and are known for their small size.

**Hint**: Remember that viroids are plant pathogens and are different from viruses.

2. **Discovery of Viroids**:
- Viroids were discovered by the scientist Theodore O. Diener in 1971. This is an important historical fact about viroids.

**Hint**: Keep in mind the name of the scientist and the year of discovery.

3. **Characteristics of Viroids**:
- Viroids are extremely small, typically consisting of up to 300 nucleotides.
- They contain only RNA as their genetic material and do not have a protein coat.

**Hint**: Focus on the fact that viroids have RNA as their genetic material and lack a protein coat.

4. **Molecular Weight**:
- The molecular weight of viroids is very low, which is consistent with their small size.

**Hint**: Recall that viroids are characterized by low molecular weight.

5. **Analyzing the Options**:
- **Option 1**: States that viroids cause potato spindle tuber disease. This is correct.
- **Option 2**: States that viroids cause Tobacco Mosaic Disease. This is incorrect because Tobacco Mosaic Disease is caused by Tobacco Mosaic Virus (TMV), not viroids.
- **Option 3**: States that viroids were discovered by T.O. Diener in 1971. This is correct.
- **Option 4**: States that viroids have low molecular weight RNA. This is correct.

**Hint**: Compare each statement with the characteristics of viroids to identify the incorrect one.

6. **Conclusion**:
- The statement that is not correct for viroids is **Option 2**, which claims that viroids cause Tobacco Mosaic Disease.

### Final Answer:
The statement that is not correct for viroids is **Option 2**: "Viroids cause Tobacco Mosaic Disease."