The endogenous levels of auxin and cytokinin in teratoma and unorganized tobacco (Nicotiana tabacum L. var Wisconsin #38) crown gall tumor tissues were determined. Teratoma tissues contain levels of auxin and cytokinin favorable for shoot formation, whereas unorganized tumors contain levels of auxin that suppress shoot formation. This conclusion is based upon the observation that when levels of...

A cloned tobacco crown gall tumor, 1595501, incited by A. tumefaciens strain 15955 was studied. Molecular analysis of the organization of the T-DNA by means of Southern transfer and hybridization techniques indicated that the 1595501 tumor has about 10 copies of TL DNA, five of which are complete TL DNA, whereas most octopine tumors have only one to two copies of complete TL DNA. Hybridization ...

Experiments using different species of the plant Nicotiana and strains of the bacterium Agrobacterium tumefaciens showed that teratoma formation from crown galls was dependent on the combination of bacterial Ti plasmid and host plant used.

The cactus Mammillaria gracillis Pfeiff. was propagated in vitro on Murashige and Skoog (MS) medium without any growth regulators. At the bases of some plants abundant callus masses developed. Lower agar and higher MS salt concentrations stimulated callus pro­ duction. In the culture, morphologically normal and hyperhydric shoots were regenerated. The growth of crown-gall tumour was induced on ...

Agrobacterium tumefaciens is a Gram-negative soil phytopathogenic bacterium that causes the crown gall disease of dicotyledonous plants, which is characterized by a tumorous phenotype. It induces the tumor by transferring a segment of its Ti plasmid DNA (transferred DNA, or T-DNA) into the host genome and genetically transforming the host. One century has past after A. tumefaciens was firstly i...