State how has Agrobacterium tumifaciens been made a useful cloning vector to transfe rDNA to plant cells.

• Agrobacterium tumefaciens, a plant pathogen, is commonly used as a vector for the introduction of foreign genes into plants and consequent regeneration of transgenic plants.

• Agrobacterium infects plant tissues by teansferring its plasmid T-DNA to the plant genome.

• The desired gene that has to be transferred to a particular plant is inserted in a plasmid T-DNA of Agrobacterium.

• This engineered Agrobacterium is allowed to infect that particular pant so that it can transfer the desired gene to the plant genome through its T-DNA.

• It is a direct gene transfer method which eliminate the need for regeneration from tissue explants and therefore it is simple, easy and successful method.