NEETZoologyBiotechnology - Principles and Processes
Agrobacterium tumefaciens , a pathogen of several dicot plants, is able to deliver a piece of DNA known as 'T-DNA' to transform normal plant cells into a tumor. What specific modification is made to its naturally occurring Ti plasmid so that it can be used as a cloning vector for plants?
Options
- AThe entire T-DNA region is deleted to prevent the formation of tumors in the host plant.
- BAn animal origin of replication is added to allow its multiplication in a wider range of hosts.
- CAmpicillin resistance genes are introduced to facilitate the infection of plant cells.
- DThe tumor-causing genes are removed, but the plasmid retains its mechanism to deliver the DNA of interest.
Correct answer
D. The tumor-causing genes are removed, but the plasmid retains its mechanism to deliver the DNA of interest.
Step-by-step solution
The tumor inducing (Ti) plasmid of Agrobacterium tumefaciens has been modified into a cloning vector which is no more pathogenic to the plants but is still able to use the mechanisms to deliver genes of our interest into a variety of plants. This is achieved by 'disarming' the plasmid, which involves removing the pathogenic (tumor-causing) genes from the T-DNA region while retaining the sequences necessary for the transfer of DNA into the plant cell. Deleting the entire T-DNA region would destroy its ability to tra