Nitrogen fixation by Rhizobium cultured on a defined medium

Pagan, Janet; Child, J. J.; Scowcroft, W. R.; Gibson, A. H.

doi:10.1038/256406a0

Cited by 217 publications

(84 citation statements)

References 16 publications

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“…Previously, nitrogenase activity had been observed only in what appeared to be loose associations of rhizobia with tissue cultured plant cells (Holsten et a/., 1971;Child & LaRue, 1974;Philips, 1974;Child, 1975;. Studies of rhizobia grown in defined liquid media showed that a low concentration of dissolved oxygen is required for development of nitrogenase activity (Keister, 1975;Tjepkema & Evans, 1975).…”

Section: Introductionmentioning

confidence: 99%

“…Immunological studies (Bishop et al, 1975) indicated that free-living rhizobia were able to synthesize a component of nitrogenase, and nitrogenase activity was subsequently demonstrated in free-living bacteria growing on an air-exposed agar surface (Pagan et al, 1975;Kurz & LaRue, 1975;McComb et al, 1975). Previously, nitrogenase activity had been observed only in what appeared to be loose associations of rhizobia with tissue cultured plant cells (Holsten et a/., 1971;Child & LaRue, 1974;Philips, 1974;Child, 1975;.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Nitrogenase Activity of Rhizobium japonicum Growing on Agar Surfaces in Relation to Slime Production, Growth and Survival

Wilcockson¹,

Werner²

1978

Journal of General Microbiology

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nitrogenase Activity of Rhizobium japonicum Growing on Agar Surfaces in Relation to Slime Production, Growth and Survival

Wilcockson¹,

Werner²

1978

Journal of General Microbiology

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“…ACC deaminase production [12], nitrogen fixation [13], phosphate solubilization [14], IAA production [15], siderophore production [16] and HCN production [17] were determined as per standard procedures.…”

Section: Plant Growth Promoting Characteristics Of Dptmentioning

confidence: 99%

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation

Goel¹,

Pandey

Sood³

et al. 2011

Indian J Microbiol

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Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT T ) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 9 10 -6 . DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate.

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“…Under specialized cultural conditions, several bradyrhizobial strains, including B. japonicum, are able to reduce N, to ammonia in free-living culture (Keister, 1975;Pagan et al, 1975;Kurz & Larue, 1975;McComb et al, 1975;Tjepkema & Evans, 1975). Optimal conditions for asymbiotic N2 fixation include the presence of organic acids as carbon and energy source, a growth-promoting nitrogen source, and extreme microaerobiosis.…”

Section: Discussionmentioning

confidence: 99%

“…Some bradyrhizobial strains can be induced to fix N2 in free-living culture under specialized conditions (Keister, 1975;Pagan et al, 1975;Kurz & Larue, 1975;McComb et al, 1975;Tjepkema & Evans, 1975). These conditions include both provision of a source of fixed nitrogen (preferably glutamate) and the presence of O2 as an electron acceptor for oxidative phosphorylation.…”

Section: T H Adams a N D B K Chelmmentioning

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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Nitrogen fixation by Rhizobium cultured on a defined medium

Cited by 217 publications

References 16 publications

Nitrogenase Activity of Rhizobium japonicum Growing on Agar Surfaces in Relation to Slime Production, Growth and Survival

Nitrogenase Activity of Rhizobium japonicum Growing on Agar Surfaces in Relation to Slime Production, Growth and Survival

Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation

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

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