Regulation of Nitrogen Fixation Genes

Gussin, Gary N.

doi:10.1146/annurev.genet.20.1.567

Cited by 58 publications

(82 citation statements)

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“…Activation by NifA also occurs in Rhizobium and Bradyrhizobium spp. (Gussin et al, 1986) and in Azorhizobium caulinodans (de Bruijn et al, 1988), and the presence of a -24/-12 promoter sequence suggests a dependence on RpoN in the majority of nifpromoters sequenced to date.…”

Section: Introductionmentioning

confidence: 99%

Sequence and structural organization of a nifA-like gene and part of a nifB-like gene of Herbaspirillum seropedicae strain Z78

Souza

Funayama²,

Rigo³

et al. 1991

Journal of General Microbiology

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Section: Introductionmentioning

confidence: 99%

Sequence and structural organization of a nifA-like gene and part of a nifB-like gene of Herbaspirillum seropedicae strain Z78

Souza

Funayama²,

Rigo³

et al. 1991

Journal of General Microbiology

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“…In enteric bacteria the use of these two pathways is genetically controlled in response to the availability of ammonia. These enzymes form part of a general nitrogen control system (see Gussin et al, 1986, for a review) which includes a number of enzymes involved in the breakdown of nitrogenous compounds. When ammonia is present at high concentrations, the genes for GS and other enzymes under nitrogen control are repressed, and GDH is induced.…”

Section: Introductionmentioning

confidence: 99%

Regulation of Glutamine Synthetase Isoenzymes in Rhizobium leguminosarum biovar viceae

Rossi¹,

Defez²,

Chiurazzi³

et al. 1989

Microbiology

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Ammonia assimilation in Rhizobium leguminosarum biovar viceae strain RCRlOO 1 (hereafter called R . leguminosarum) appears to take place only through the glutamine synthetase/glutamate synthase pathway since (a) no glutamate dehydrogenase was detected in crude extracts of bacteria grown in different nitrogen sources, and (b) the growth rate on glutamine as a nitrogen source was faster than that observed on NH4Cl. In contrast to reports for other Rhizobium species, R . leguminosarum can definitely utilize NH4C1 for growth. R. Ieguminosarum contains two glutamine synthetase isoenzymes, GSI and GSII, which can be detected in the presence of each other by differential heat stability, or separated by affinity chromatography or immunoabsorption with an antiserum raised against pure GSI. GSII does not cross-react with an anti-GSI antiserum. GSI was shown to be reversibly adenylylated and it was also shown that adenylylation inhibits the biosynthetic activity of this enzyme, in a similar way to that reported for Escherichia coli glutamine synthetase and in contrast to that observed for glutamine synthetase of Rhizobium sp. strain ANU289. The apparent adenylylation level in different growth conditions changes from 21% to 99%, indicating a physiological role of this posttranslational modification in the in vivo regulation of GSI activity. The intracellular concentration of GSI varies very little when R . leguminosarum is grown on different nitrogen sources (twofold when measured by the transferase assay, or fourfold when measured by ELISA). In addition, the concentration of mRNA specific for GSI in different nitrogen sources does not show appreciable differences. The intracellular concentration of GSII varies from a specific activity value higher than 1000 when R . leguminosarum is grown on glutamate or nitrate, to an undetectable level when grown on NH4C1. When NH4C1 is added to a culture growing in glutamate, GSII activity is rapidly diluted out, suggesting a post-translational mechanism of enzyme inhibition or inactivation. Chloramphenicol prevents the disappearance of GSII activity, thus suggesting that protein synthesis is required for this process.

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“…Ntr-like control of nitrogenase expression has previously been described for bradyrhizobia (Ludwig, 1980a, 6;Bergerson & Turner, 1978) and rhizobia (Szeto et al, 1987). The glnII gene promoter shares sequence homology in the -10 to -25 region with B. japonicum nifpromoters (Carlson et al, 1987) and with promoters from other bacteria that are controlled by nitrogen availability (Ntr control; Magasanik, 1982;Ausubel, 1984;Gussin et al, 1986). A gene, termed nifA, that is required for both microaerobic and symbiotic induction of nif and glnII gene expression in B. japonicum has been characterized (Fischer et al, 1986;Adams, 1986).…”

Section: Discussionmentioning

confidence: 95%

“…In contrast, no post-translational modification of GSII has been observed. Transcription of the gene encoding GSII (glnll) under aerobic growth conditions is controlled by a mechanism that resembles the Ntr system (Carlson et al, 1987) of enteric bacteria (Magasanik, 1982;Gussin et al, 1986); growth conditions that limit nitrogen source activate transcription of the gln11 gene.…”

Section: Introductionmentioning

confidence: 99%

Effects of Oxygen Levels on the Transcription of nif and gln Genes in Bradyrhizobium japonicum

Adams

Chelm

1988

Microbiology

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The transciption of genes that function in N2 fixation (nif) and nitrogen assimilation (gln11) in Bradyrhizobiurn japonicum is coordinately induced in response to O2 limitation as well as symbiotic development. We have determined the relative steady-state mRN A levels for the nzfH, nfDK and glnll transcription units in bradyrhizobial cells grown under a variety of levels of aerobiosis and in cells isolated from soybean root nodules. All three transcripts are found in cells grown in a rich medium sparged with O2 concentrations of 5 % (v/v) or less. This expression is qualitatively similar to that observed for Bradyrhizobium during symbiotic development. Potential physiological mechanisms for the coordinate control of these genes are discussed.

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Regulation of Nitrogen Fixation Genes

Cited by 58 publications

References 0 publications

Sequence and structural organization of a nifA-like gene and part of a nifB-like gene of Herbaspirillum seropedicae strain Z78

Sequence and structural organization of a nifA-like gene and part of a nifB-like gene of Herbaspirillum seropedicae strain Z78

Regulation of Glutamine Synthetase Isoenzymes in Rhizobium leguminosarum biovar viceae

Effects of Oxygen Levels on the Transcription of nif and gln Genes in Bradyrhizobium japonicum

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