In marked contrast, around 16,000 species within the 650–700 genera of legumes have been identified as forming nitrogen-fixing symbioses with rhizobia. If such diversity is taken as a measure of evolutionary success or fitness, the legume family within the Fabales has been considerably more successful than any other family of nodulating plants in the closely-related orders. Why is it that nitro...

The bacteria capable of fixing atmospheric nitrogen were isolated from cassava cultivated soils Vietnam. potential isolates identified by analyzing the 16S rRNA gene and morphological, biochemical, cultural characteristics. selected assigned to species Bacillus sp. DQT2 M17, subtilis DTAN6 megaterium DSHB I8. effect culture conditions on nitrogen-fixing activity three studied obtained results s...

The family Acetobacteraceae currently includes three known nitrogen-fixing species, Gluconacetobacter diazotrophicus, G. johannae and G. azotocaptans. In the present study, acetic acid-producing nitrogen-fixing bacteria were isolated from four different wetland rice varieties cultivated in the state of Tamilnadu, India. Most of these isolates were identified as G. diazotrophicus on the basis of...

Two nitrogen-fixing root nodule symbioses between soil bacteria and higher plants have been described: the symbiosis between legume and rhizobia and actinorhizal symbioses between plants belonging to eight angiosperm families and the actinomycete Frankia. We have recently shown that the subtilisin-like Ser protease gene cg12 (isolated from the actinorhizal plant Casuarina glauca) is specificall...

The activity of NifA, the transcriptional activator of the nitrogen fixation (nif) gene, is tightly regulated in response to ammonium and oxygen. However, the mechanisms for the regulation of NifA activity are quite different among various nitrogen-fixing bacteria. Unlike the well-studied NifL-NifA regulatory systems in Klebsiella pneumoniae and Azotobacter vinelandii, in Rhodospirillum rubrum ...

Some methane-oxidizing bacteria (methanotrophs) are known to be capable of expressing nitrogenase and utilizing N2 as a nitrogen source. However, no sequences are available for nif genes in these strains, and the known nitrogen-fixing methanotrophs are confined mainly to a few genera. The purpose of this work was to assess the nitrogen-fixing capabilities of a variety of methanotroph strains. n...