Agrobacterium tumefacines is a gram negative non sporing, motile, rod shaped bacterium, closely related to Rhizobium. It is found commonly on and around root surfaces. The region termed rhizosphere where it seems to survive by using nutrients that leak from the root tissues. But it infects only through the wound-site either naturally occurring or caused by transplanting of seedling and nursery stock. It is harmful to plants and useful to scientists for the same reason i.e. it transfers DNA into plant genomes found in soil worldwide. A. tumefaciens cause crown gall disease of a wide range of dicot (broad leaved) plants especially members of rose family by transferring its own DNA into plant cells. But in laboratory, the ability to move all sorts of genes into plants has made the microbe the standard tool for investigating plant genetics and modifying crops.