Agrobacterium tumefaciens is a naturally occurring gram negative soil bacteria that consists of Ti plasmid. It has the ability to transform plants so are considered as the natural genetic engineer. A. Tumefaciens cause crown gall disease by transferring a defined segment of DNA also called T-DNA or transferred DNA, from its tumor inducing large plasmid into an infected wound of dicotyledonous plants. So we can insert a desired fragment into Ti plasmid of A. Tumefaciens and can naturally get it cloned or expressed.
