Isolation and characterization of a ntrC mutant of Bradyrhizobium (Parasponia) sp. ANU289

M. K. Udvardi, D. L. Lister, D. A. Day

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


A mutant of Bradyrhizobium (Parasponia) sp. ANU289 affected in the regulation of nitrogen metabolism was isolated. The mutant, designated ANU293, was unable to induce ammonium transport (Amt), nitrate reductase (NR) or dutamine synthetase II (GSII) activities under conditions that induce these activities in the wild-type. However, glutamine synthetase I (GSI), which is expressed constitutively in the wild-type, was present at normal levels in the mutant. The mutant also retained the ability to fix nitrogen in vitro and in planta, although nodule development on siratro (Macroptilium atropurpureum) was retarded. Southern blot analysis showed that ntrC, the product of which is involved in regulation of nitrogen metabolism, is the site of pSUP1021 insertion in ANU293. These results indicate that the transcriptional activator NtrC is required for the expression of Amt, NR and GSII, but not GSI or nitrogenase in Bradyrhizobium (Parasponia) sp. ANU289.

Original languageEnglish
Pages (from-to)1019-1025
Number of pages7
JournalJournal of General Microbiology
Issue number5
Publication statusPublished - 1 May 1992
Externally publishedYes


Dive into the research topics of 'Isolation and characterization of a ntrC mutant of Bradyrhizobium (Parasponia) sp. ANU289'. Together they form a unique fingerprint.

Cite this