Describe the role of Agrobacterium tumefaciens in transforming a plant cell.

Agrobacterium tumefaciens:

Agrobacterium tumefaciens is a soil bacterium that infects the plants through the wounded region and causes gall tumors in plants. This bacterium contains a plasmid, Ti plasmid or Tumor inducing plasmid. The T-DNA segment of the Ti plasmid integrates itself into the plant cell’s genome to induce tumor formation in plants. This property of the plasmid makes it an effective vector for transferring foreign genes into plant cells.


Role of Agrobacterium tumefaciens in transforming plants:

Agrobacterium tumefaciens contains a Ti plasmid which has T- DNA. This T-DNA is integrated into the plant genome upon the infection with this bacterium. This bacterium is the natural genetic engineer of plants.

To use Ti plasmid as a cloning vector, the T-DNA segment of the Ti plasmid can be genetically modified to carry foreign DNA.
A restriction enzyme can be used to cut the T- DNA segment at a specific site and the DNA fragment carrying the gene of interest can be inserted into this segment using ligase enzyme. Once modified, the T-DNA becomes incapable of inducing tumours.