NEETZoologyBiotechnology - Principles and Processes
A scientist attempts to create a transgenic dicot plant using an Agrobacterium -based vector. Upon observation, the plant successfully expresses the introduced gene of interest, but it also develops large crown gall tumors at the sites of infection. Which of the following is the most likely procedural error made by the scientist during the preparation of the vector?
Options
- AThe gene of interest was inserted into the ori region of the plasmid.
- BThe scientist used a retroviral vector instead of Agrobacterium .
- CThe plant cells rejected the recombinant DNA after transformation.
- DThe scientist failed to disarm the Ti plasmid before inserting the gene of interest.
Correct answer
D. The scientist failed to disarm the Ti plasmid before inserting the gene of interest.
Step-by-step solution
The development of crown gall tumors indicates that the wild-type T-DNA, which carries tumor-inducing genes, was successfully transferred to the plant cells. For Agrobacterium tumefaciens to be used as a safe cloning vector, its Ti (tumor-inducing) plasmid must be 'disarmed' by removing the tumor-causing genes while retaining the DNA transfer mechanism. Since the plant expresses the gene of interest, the transformation was successful, meaning the ori was intact (ruling out option 1) and the DNA was not rejected (ru