Agrobacterium tumefaciens, a plant pathogen, is characterized by the unique feature of interkingdom DNA transfer. This soil bacterium is able to transfer a fragment of its DNA, called T-DNA (transferred DNA), to the plant cell where T-DNA is integrated into the plant genome leading to "genetic colonization" of the host. The fate of T-DNA, its processing, transfer and integration, resembles the journey of Odysseus, although our hero returns from its long trip in a slightly modified form.