The tumor including capacity of _A_ is located in large extra-chromosomal plasmid called Ti plasmid. Choose the option which correctly fills up the blanks _A_

Options

A. Thermus aquaticus
B. Salmonella typhimurium
C. E.coli
D. Agrobacterium tumefaciens

Answer

To solve the question about the tumor-inducing capacity of a bacterium located in the Ti plasmid, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Ti Plasmid**:
- The Ti plasmid (Tumor-inducing plasmid) is a large plasmid found in certain bacteria, particularly in Agrobacterium tumefaciens. This plasmid is responsible for the transfer of DNA into plant cells, leading to tumor formation.

2. **Identifying the Bacterium**:
- The question asks which bacterium has the tumor-inducing capacity associated with the Ti plasmid. The options provided are:
- Thermus aquaticus
- Salmonella typhimurium
- E. coli
- Agrobacterium tumefaciens

3. **Analyzing the Options**:
- **Thermus aquaticus**: Known for Taq polymerase, not related to tumor formation.
- **Salmonella typhimurium**: Causes typhoid fever, not related to tumor induction.
- **E. coli**: A model organism for genetic engineering but does not induce tumors.
- **Agrobacterium tumefaciens**: Known for its ability to induce tumors in plants through the transfer of T-DNA from its Ti plasmid.

4. **Conclusion**:
- The correct answer to fill in the blank _A_ is **Agrobacterium tumefaciens**. This bacterium is responsible for the tumor-inducing capacity associated with the Ti plasmid.

### Final Answer:
_A_ = Agrobacterium tumefaciens

---