Which one is associated with Agrobacterium tumifactiens?
A. Tumor B. Ti plasmid C. T-DNA D. Cancerous cells

Options

A. A,B
B. B,C
C. A,B,C
D. A,B,C,D

Answer

To determine which option is associated with Agrobacterium tumefaciens, let's analyze the given choices step by step.

### Step-by-Step Solution:

1. **Understanding Agrobacterium tumefaciens**:
- Agrobacterium tumefaciens is a soil bacterium known for its ability to transfer DNA to plant cells, which is why it is often referred to as a "natural genetic engineer."

2. **Analyzing the Options**:
- **A. Tumor**: Agrobacterium tumefaciens is known to cause tumor-like growths in plants, specifically a condition called crown gall disease. This occurs when the bacterium transfers part of its DNA (T-DNA) into the plant genome, leading to uncontrolled cell division.
- **B. Ti plasmid**: This is a large plasmid found in Agrobacterium tumefaciens that carries the T-DNA and is crucial for the bacterium's ability to induce tumors in plants.
- **C. T-DNA**: This is the transferred DNA segment from the Ti plasmid that integrates into the plant genome and is responsible for the tumor formation.
- **D. Cancerous cells**: While tumor formation in plants is similar to cancer in animals, the term "cancerous cells" is typically used in the context of vertebrates and is not directly associated with Agrobacterium tumefaciens.

3. **Identifying the Correct Associations**:
- Based on the explanations:
- Tumor (A) is associated with Agrobacterium tumefaciens because it causes tumor-like growths in plants.
- Ti plasmid (B) is associated as it contains the T-DNA responsible for tumor induction.
- T-DNA (C) is directly associated as it is the DNA that gets transferred and causes the tumor formation.
- Cancerous cells (D) are not associated with Agrobacterium tumefaciens as they refer to uncontrolled cell growth in animals.

4. **Conclusion**:
- The correct associations with Agrobacterium tumefaciens are **A. Tumor, B. Ti plasmid, and C. T-DNA**. Therefore, the answer is **A, B, C**.