Mycoplasma causes a disease

Options

A. Tobacco
B. Citrus canker
C. Apple fireblight
D. Little leaf disease.

Answer

### Step-by-Step Solution:

1. **Understanding Mycoplasma**:
- Mycoplasma are the smallest microorganisms known. They are unique because they lack a cell wall, which distinguishes them from other bacteria. Instead, they have a plasma membrane that contains their cytoplasm, DNA, and RNA.

2. **Identifying the Disease**:
- Among the options provided (tobacco, citrus canker, apple fire blight, little leaf disease), we need to identify which disease is caused by Mycoplasma.

3. **Recognizing the Correct Disease**:
- The disease caused by Mycoplasma is known as "little leaf disease." This disease primarily affects plants, particularly brinjal (eggplant).

4. **Symptoms of Little Leaf Disease**:
- The symptoms include:
- Reduction in the size of leaves.
- The leaves appear in a rosette formation.
- Leaves become narrow, soft, smooth, and yellowish in color.

5. **Transmission of Little Leaf Disease**:
- Little leaf disease is transmitted by a vector known as the leaf hopper. This insect acts as a carrier of the Mycoplasma, facilitating the spread of the disease among plants.

6. **Conclusion**:
- Based on the information gathered, the correct answer to the question "Mycoplasma causes a disease" is option 4: little leaf disease. The other options (tobacco, citrus canker, and apple fire blight) are not caused by Mycoplasma.