%0 Journal Article %A RAINA, J. L. %A MODI, V. V. %T Genetic Transformation in Rhizobium %D 1969 %J Microbiology, %V 57 %N 1 %P 125-130 %@ 1465-2080 %R https://doi.org/10.1099/00221287-57-1-125 %I Microbiology Society, %X SUMMARY Mutants of ground nut (Rhizobium cowpea group) strain GR3 were isolated using ultraviolet radiation and N-methyl-N′-nitrosoguanidine (NTG) as mutagenic agents. An adenine-requiring mutant was used as the recipient and its wild type as the donor in transformation studies. Initially minimal medium supplemented with 2 μg. adenine/ml. was used for the development of competence. The maximum transformation frequency was obtained after about 120 min. incubation. Supplementation of minimal medium with yeast extract and vitamin-free Casamino acids without the addition of adenine stimulated competence to a large extent. The competence was not further stimulated by any of the divalent ions used. The optimum DNA concentration for maximum transformation frequency was about 50 μg./ml. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-57-1-125