Presence of unintended Agrobacterium tumefaciens cloning vector sequences in genetically modified plants.

Agrobacterium transformation was used in the production of genetically modified plants from oilseed rape (Brassica napus) and tobacco (Nicotiana tabacum). After inoculation stop with the antibiotic timentin, a subsequent one-week treatment eliminated the vector bacterium from the oilseed rape plate explant cultures. From the tobacco, however, we recorded vector-derived signals one week after potting the regenerants in the greenhouse and still 10 weeks later. Genetically modified plants produced through Agrobacterium-transformation therefore cannot be guaranteed to be completely free of unintended vector sequences after antibiotic treatment.