Interactions of Agrobacterium tumefaciens with soybean (Glycine max (L.) Merr.) leaf explants in tissue culture

Wounded petiole surfaces of excised soybean (Glycine max (L.) Merr.) leaves of 'Peking' formed neoplastic growths testing positive for opines after inoculation with a tumorigenic strain of Agrobacterium tumefaciens. During the 48-h inoculation period, uninoculated explants and explants inoculated with A136 (avirulent), A208 (tumorigenic), and ASE1-200 (nontumorigenic) strains of A. tumefaciens showed initiation of mitotic activity at the wound surface conforming with classical descriptions of the wound response; however, shortly after explant transfer to tissue culture medium, morphogenetic patterns in explants inoculated with tumorigenic A. tumefaciens deviated from the uninoculated and A136 inoculated controls. This developmental deviation was correlated to the presence of the Ti plasmid in the bacterium. Explants inoculated with nontumorigenic A. tumefaciens showed a morphogenetic pattern intermediate between the controls and explants inoculated with tumorigenic bacteria. This suggests that the latter ...