Re-examination of transformation within different species of Rhizobium

Investigations of the phenomenon of transformation in Rhizobium were carried out. Streptomycin resistance (str) was the genetic marker used in all experiments, with the exception of auxotrophic strains. Twenty-one experiments were performed on nine different Rhizobium strains. Some of these strains were previously reported to be transformed, while others had no prior history of transformation. Different conditions which are thought to affect the development of competence were used. In these experiments no positive results were obtained. The possibility that the experiments failed, due to inactivation of donor DNA during its preparation, was ruled out by comparison with results obtained with strains of Bacillus subtilis.