Identification of a functional fur gene in Bradyrhizobium japonicum

The recent identification of the iron response regulator (Irr) in Bradyrhiz obium japonicum raised the question of whether the global regulator Fur is present in that organism. A fur gene homolog was isolated by the functional complementation of an Escherichia coli fur mutant. The B. japonicum Fur bo und to a Fur box DNA element in vitro, and a fur mutant grown in iron-reple te medium was derepressed for iron uptake activity. Thus, B. japonicum expr esses at least two regulators of iron metabolism.