By using proteins from TMV (Tobacco-mosaic virus) and RNA from HRV (Holmes ribrass virus), a chimeric virus particle was synthesized by Fraenkel-conrat and singer. It was then used for infection of tobacco leaves. They found that

Options

A. no infection was there as tobacco plant infection by DNA viruses only
B. leaves developed symptoms of TMV and HRV both
C. leaves developed symptoms of TMV
D. leaves developed symptoms of HRV

Answer

### Step-by-Step Solution:

1. **Understanding the Components**:
- The experiment involves two viruses: Tobacco Mosaic Virus (TMV) and Holmes Ribgrass Virus (HRV).
- TMV provides the protein coat, while HRV contributes the RNA.

2. **Synthesis of Chimeric Virus**:
- A chimeric virus particle is created by combining the protein from TMV with the RNA from HRV. This means the new virus has the external structure of TMV but the internal genetic material of HRV.

3. **Infection of Tobacco Leaves**:
- The synthesized chimeric virus is then used to infect tobacco leaves. This step is crucial as it allows observation of the symptoms caused by the virus.

4. **Observation of Symptoms**:
- After infection, the tobacco leaves exhibit symptoms characteristic of HRV, which are local lesions. This indicates that the genetic material (RNA) from HRV is responsible for the symptoms observed.

5. **Conclusion**:
- The experiment leads to the conclusion that the protein coat (from TMV) does not determine the symptoms of the virus. Instead, it is the RNA (from HRV) that carries the genetic information necessary for causing the disease. This supports the idea that RNA can serve as genetic material in some viruses.