Nif' gene for nitrogen fixation in cereal crops like wheat jowar etc., is introduced by cloning

Options

A. Rhizobium meliloti
B. Bacillus thuringiensis
C. Rhizopus stolonifer
D. Agrobacterium tumefaciens

Answer

**Step-by-Step Solution:**

1. **Understanding NIF Genes**: The NIF genes are responsible for encoding enzymes that facilitate the process of nitrogen fixation, which converts atmospheric nitrogen into a usable form for living organisms.

2. **Identifying the Context**: The question specifically mentions the introduction of the NIF gene into cereal crops like wheat and jowar through cloning techniques.

3. **Analyzing the Options**: The options provided are:
- A) Rhizobium mellilotae
- B) Bacillus thuringiensis
- C) Rhizopus stolonifer
- D) Agrobacterium tumefaciens

4. **Evaluating Each Option**:
- **Rhizobium mellilotae**: This is a gram-negative bacterium known for its ability to fix atmospheric nitrogen, particularly in symbiosis with legumes. It is the correct choice for introducing the NIF gene.
- **Bacillus thuringiensis**: This bacterium is known for producing Bt toxin, which is used as a pesticide, not for nitrogen fixation.
- **Rhizopus stolonifer**: This is a fungus commonly known as black bread mold, which does not play a role in nitrogen fixation.
- **Agrobacterium tumefaciens**: While this bacterium is used in genetic engineering, particularly for plant transformation, it is not directly involved in nitrogen fixation.

5. **Conclusion**: Based on the analysis, the correct answer is **A) Rhizobium mellilotae**, as it is the bacterium that can introduce the NIF gene for nitrogen fixation in cereal crops.

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