Which one is associated with Agrobacterium tumifaciens ?
(A) Tumor (B) Tiplasmid .
(C) T - DNA (D) Cancerous cells

Options

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

Answer

To solve the question "Which one is associated with Agrobacterium tumefaciens?" we need to analyze the options provided:

1. **Understanding Agrobacterium tumefaciens**:
- Agrobacterium tumefaciens is a bacterium that acts as a pathogen for dicot plants. It is known for its ability to transfer genetic material into plant cells.

2. **Analyzing the options**:
- **(A) Tumor**: Agrobacterium tumefaciens is known to cause tumor formation in plants, specifically crown gall tumors. This is a significant association.
- **(B) T-plasmid**: The bacterium contains a plasmid known as the T-I (Tumor Inducing) plasmid, which is essential for the transfer of DNA into the plant cells.
- **(C) T-DNA**: The T-DNA (transfer DNA) is the portion of the T-plasmid that is transferred to the plant cells and integrates into the plant genome, leading to tumor formation.
- **(D) Cancerous cells**: While tumor formation in plants can be likened to cancer, cancerous cells are more commonly associated with viruses in animals, not specifically with Agrobacterium tumefaciens.

3. **Conclusion**:
- Based on the analysis, options A (Tumor), B (T-plasmid), and C (T-DNA) are directly associated with Agrobacterium tumefaciens. Option D (Cancerous cells) is not specifically associated with it.

Thus, the correct answer is A, B, and C.

### Step-by-step Solution:
1. Identify what Agrobacterium tumefaciens is and its role as a pathogen in plants.
2. Examine each option:
- A: Tumor - Yes, associated with tumor formation.
- B: T-plasmid - Yes, it contains the T-I plasmid.
- C: T-DNA - Yes, it refers to the DNA transferred to the plant.
- D: Cancerous cells - No, not specifically associated.
3. Conclude that options A, B, and C are correct.