agrobacterium tumefaciens

Agrobacterium tumefaciens (updated scientific name: Rhizobacterium tumefaciens) is the causal agent of crown gall disease (the formation of tumours) in over 140 species of dicot.

It is a rod shaped, Gram negative soil bacterium. Symptoms are caused by the insertion of a small segment of DNA (known as the T-DNA, for 'transfer DNA'), from a plasmid, into the plant cell, which is incorporated at a semi-random location into the plant genome.

Agrobacterium tumefaciens is an alphaproteobacterium of the family Rhizobiaceae.

Economically, A. tumefaciens is a serious pathogen of walnuts, grape vines, stone fruits, nut trees, sugar beets, horse radish and rhubarb.