This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Martin, G B Articles by Chelm, B K Search for Related Content PubMed PubMed Citation Articles by Martin, G B Articles by Chelm, B K

 Previous Article  |  Next Article 

J Bacteriol. 1988 December; 170(12): 5452-5459

research-article

Role of the Bradyrhizobium japonicum ntrC gene product in differential regulation of the glutamine synthetase II gene (glnII).

MSU/DOE Plant Research Laboratory, Michigan State University, East Lansing 48824-1312.

ABSTRACT

We isolated the ntrC gene from Bradyrhizobium japonicum, the endosymbiont of soybean (Glycine max), and examined its role in regulating nitrogen assimilation. Two independent ntrC mutants were constructed by gene replacement techniques. One mutant was unable to produce NtrC protein, while the other constitutively produced a stable, truncated NtrC protein. Both ntrC mutants were unable to utilize potassium nitrate as a sole nitrogen source. In contrast to wild-type B. japonicum, the NtrC null mutant lacked glnII transcripts in aerobic, nitrogen-starved cultures. However, the truncated-NtrC mutant expressed glnII in both nitrogen-starved and nitrogen-excess cultures. Both mutants expressed glnII under oxygen-limited culture conditions and in symbiotic cells. These results suggest that nitrogen assimilation in B. japonicum is regulated in response to both nitrogen limitation and oxygen limitation and that separate regulatory networks exist in free-living and symbiotic cells.

This article has been cited by other articles:

• Patriarca, E. J., Tate, R., Iaccarino, M. (2002). Key Role of Bacterial NH4+ Metabolism in Rhizobium-Plant Symbiosis. Microbiol. Mol. Biol. Rev. 66: 203-222 [Abstract] [Full Text]  
• Nienaber, A., Huber, A., Göttfert, M., Hennecke, H., Fischer, H.-M. (2000). Three New NifA-Regulated Genes in the Bradyrhizobium japonicum Symbiotic Gene Region Discovered by Competitive DNA-RNA Hybridization. J. Bacteriol. 182: 1472-1480 [Abstract] [Full Text]