Question

What modification is done on the Ti plasmid of Agrobacterium tumefaciens to convert it into a cloning vector?

Answer 1

Introduction to Ti plasmid:

Agrobacterium tumefaciens is a bacterial plant pathogen which carries the Ti plasmid or tumor inducing plasmid (extrachromosomal DNA). 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.

Modification in Ti plasmid:

To use Ti plasmid as a cloning vector, the T-DNA segment of the Ti plasmid can be genetically modified to carry the desired 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 tumors, however, transfers the desired gene into the host plant cell.