crown-gall disease

crown-gall disease

a tumerous outgrowth of the stem in many plants, such as roses and fruit trees, caused by the bacterium Agrobacterium tumefaciens. The bacterium is useful in that it contains a PLASMID (Ti ‘tumour-inducing’ plasmid), part of which can fuse with normal DNA of the host plant cell and transfer it to a different plant, thereby enabling the transfer of specific genetic information from one species to another.