Two microbes found to be very useful in genetic engineering are

Options

A. Escherichia coli and Agrobacterium tumefaciens
B. Vibrio cholerae and a tailed bacteriophage
C. Diplococcus sp. and Pseudomonas sp.
D. Crown gall bacterium and Caenorhabditis elegans

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for two microbes that are useful in genetic engineering.

2. **Analyze the Options**:
- **Option A**: E. coli and Agrobacterium tumefaciens
- **Option B**: Vibrio coli and a tailed bacteriophage
- **Option C**: Diplococcus species and Pseudomonas species
- **Option D**: Brown gold bacterium and Acinohabitatus pelicans

3. **Evaluate Option A**:
- **E. coli**: This bacterium is widely used in genetic engineering due to its ability to take up foreign DNA easily and its role in cloning and protein production. It is a unicellular organism that has a high transformation rate.
- **Agrobacterium tumefaciens**: This bacterium is known for its ability to transfer DNA to plant cells, which is crucial for plant genetic engineering. It integrates its T-DNA into the plant genome, making it a valuable tool for creating genetically modified plants.

4. **Evaluate Other Options**:
- **Option B**: Vibrio coli is known to cause diseases in humans, and a tailed bacteriophage is a virus that infects bacteria, not typically used in genetic engineering.
- **Option C**: Diplococcus species and Pseudomonas species are also associated with human diseases and not primarily used in genetic engineering.
- **Option D**: Brown gold bacterium and Acinohabitatus pelicans do not have significant roles in genetic engineering and are associated with infections.

5. **Conclusion**: Based on the analysis, the two microbes that are very useful in genetic engineering are **E. coli** and **Agrobacterium tumefaciens**. Therefore, the correct answer is **Option A**.

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