Which of the following features cannot be assocaites with Ti plasmid of Agrobacterium tumifaciens which is modified into a cloning vector?

Options

A. Able to deliver genes of our interest a variety of plants
B. Modified into cloning vectors as it can transfer a piece of T-DNA into the plant cells
C. Pathogenic to the plants
D. Ti plasmid of Agrobacterium is a natural genetic engineer

Answer

To solve the question regarding the features associated with the Ti plasmid of Agrobacterium tumefaciens when modified into a cloning vector, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Ti Plasmid**:
- The Ti (tumor-inducing) plasmid is a naturally occurring plasmid found in Agrobacterium tumefaciens, which is known for its ability to transfer DNA to plant cells, leading to tumor formation.

2. **Analyzing the Options**:
- We need to identify which feature **cannot** be associated with the modified Ti plasmid when used as a cloning vector.

3. **Option 1**: "Deliver genes of our interest to a variety of plants."
- This feature **can** be associated with the Ti plasmid as it is modified to facilitate the transfer of desired genes into plant cells.

4. **Option 2**: "Transfer a piece of T-DNA into the plant cell."
- This feature **can** also be associated with the Ti plasmid, as the T-DNA region is specifically designed for integration into the plant genome.

5. **Option 3**: "Pathogenicity to the host plant."
- This feature **cannot** be associated with the modified Ti plasmid when used as a cloning vector. The modified plasmid is typically rendered non-pathogenic to prevent disease in the host plant.

6. **Option 4**: "Natural genetic engineering."
- This feature **can** be associated with the Ti plasmid, as it is involved in the natural process of gene transfer in plants.

7. **Conclusion**:
- The feature that cannot be associated with the modified Ti plasmid when used as a cloning vector is **Option 3: Pathogenicity to the host plant**.

### Final Answer:
**Option 3: Pathogenicity to the host plant.**

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