nif gene is found in -

Options

A. Pseudomonas
B. Salmonella
C. Rhizobium
D. Mycobacterium

Answer

**Step-by-Step Solution:**

1. **Understanding Nif Genes**: Nif genes are responsible for coding nitrogen-fixing enzymes. These enzymes are crucial for the process of converting atmospheric nitrogen (N2) into ammonia (NH3), a form that plants can utilize.

2. **Identifying Organisms with Nif Genes**: The organisms mentioned in the transcript that contain Nif genes include:
- Pseudomonas
- Salmonella
- Rhizobium
- Microbacterium

3. **Analyzing Each Organism**:
- **Pseudomonas**: This is a denitrifying bacterium, which means it does not fix nitrogen; rather, it converts nitrates back into nitrogen gas.
- **Salmonella**: This is an opportunistic human pathogen and is not involved in nitrogen fixation.
- **Rhizobium**: This is a gram-negative bacterium that forms symbiotic relationships with legumes, creating root nodules where nitrogen fixation occurs.
- **Microbacterium**: While it has a unique waxy layer, it is not primarily known for nitrogen fixation.

4. **Conclusion**: Based on the analysis, the organism that is primarily associated with nitrogen fixation through the presence of Nif genes is **Rhizobium**.

5. **Final Answer**: The Nif gene is found in **Rhizobium**.

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