Nitrogenase activity in pure cultures of spectinomycin-resistant fast and slow-growing Rhizobium

Abstract

Several strains of Rhizobium resistant to spectinomycin also had nitrogenase activity (C 2H 2 reduction and H 2 production) in static culture under 95% Ar/1%O 2/4%C 2H 2. This relationship between nitrogenase activity and spectinomycin resistance was observed in both fast-growing ( R. trifolii and R. leguminosarum) and slow-growing ( R. japonicum) rhizobia. The effect of different media and various carbon sources on nitrogenase activity was investigated in more detail in R. trifolii strain TlSp. This communication demonstrates that fast-growing rhizobia can have nitrogenase activity in the absence of any plant component.