Transcriptional regulation of cytochrome d in nitrogen-fixing Azotobacter vinelandii. Evidence that up-regulation during N2 fixation is independent of nifA but dependent on ntrA.

Moshiri, Farhad; Smith, Edward G.; Taormino, J P; Maier, Robert J.

doi:10.1016/s0021-9258(18)54479-3

Cited by 28 publications

(4 citation statements)

References 30 publications

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“…To establish the link between the regulation of rnf1 gene expression and the ammonia-excretion phenotype, deletion of the region encoding the GHKL domain of NifL was combined with insertion of two different A. vinelandii endogenous promoter sequences from the cydAB 41 and cycB 42 genes, orientated in the opposite direction to nifA transcription. The resulting strains (AvFM13, AvFM14, AvFM16, AvFM17) (Table I) were Nif + and excreted ammonia.…”

Section: Promoter Strength and Of Ammonia Excretionmentioning

confidence: 99%

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Genetic determinants of ammonia excretion in nifL mutants of Azotobacter vinelandii

Mus

Khokhani

Rugoli

et al. 2021

Preprint

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The ubiquitous diazotrophic soil bacterium Azotobacter vinelandii has been extensively studied as a model organism for biological nitrogen fixation (BNF). In A. vinelandii, BNF is regulated by the NifL-NifA two-component system, where NifL acts as an anti-activator that tightly controls that activity of the nitrogen fixation specific transcriptional activator, NifA, in response to redox, nitrogen, and carbon status. While several studies reported mutations in A. vinelandii nifL resulted in the deregulation of nitrogenase expression and the release of large quantities of ammonia, knowledge about the specific determinants for this ammonia-excreting phenotype is lacking. In this work, we report that only specific disruptions of nifL lead to large quantities of ammonia accumulated in liquid culture (~ 12 mM). The ammonia excretion phenotype is solely associated with deletions of NifL domains combined with the insertion of a promoter sequence in the opposite orientation to nifLA transcription. We further demonstrated that the strength of the inserted promoter could influence the amounts of ammonia excreted by affecting rnf1 gene expression as an additional requirement for ammonia excretion. These ammonia-excreting nifL mutants significantly stimulate the transfer of fixed nitrogen to rice. This work defines the discreet determinants that bring about A. vinelandii ammonia excretion and demonstrates that strains can be generated through simple gene editing to provide promising biofertilizers capable of transferring nitrogen to crops.

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Section: Promoter Strength and Of Ammonia Excretionmentioning

confidence: 99%

“…The AvFM13 and AvFM16 strains were obtained by gene disruption using cydAB 41 promoter sequence. The cydAB promoter region (p cydAB ) was isolated by PCR ampli cation using genomic DNA from A. vinelandii strain DJ.…”

Section: Construction Of the Avfm13 And Avfm16 Strainsmentioning

confidence: 99%

Genetic determinants of ammonia excretion in nifL mutants of Azotobacter vinelandii

Mus

Khokhani

Rugoli

et al. 2021

Preprint

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“…A specific link with Nj fixation is suggested by the observation that synthesis of cytochrome d was two-to three-fold greater in cells of Azotobacter vinelandii that were fixing N2, compared with cells that were not fixing N2. However, regulation of cytochrome d synthesis by fixed nitrogen differed from conventional nif gene regulation in that, though dependent on NtrA, it was independent of NifA (Moshiri et al, 1991). Electron transport in Azotobacter is described in detail by Yates (1987).…”

Section: {B) Aerotactic Responses Aggregation and Associationmentioning

confidence: 99%

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1992

New Phytologist

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N2 fixation is an extremely Oj-sensitive process. N,-fixing bacteria (diazotrophs) have therefore evolved a variety of strategies by which they maintain an active nitrogenase in the presence of atmospheric Oj and, in some cases, of Og generated photosynthetically. In this review, the effects of O.^ on nitrogenase activity and synthesis are described, as are the mechanisms by which diazotrophs limit O,, damage to nitrogenase. These mechanisms are classified as behavioural strategies, physical barriers or physiological and biochemical strategies. Individual diazotrophs frequently employ a combination of these. In addition, the particular problems faced by the O.^evolving cyanobacteria are discussed.

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“…Die Succinat-Dehydrogenase (Komplex II der Atmungskette) ist eines der Enzyme des zentralen Stoffwechsels, die bei G. oxydans nicht vorhanden sind (s. 3.6.2.4) (CALHOUN et al, 1993). Interessanterweise wurde gezeigt, dass bei hohen Sauerstoffkonzentrationen und diazotrophen Wachstum in Azotobacter vinelandii die Endoxidase vom Typ bd genutzt wird, bei gleichzeitig hoher Expression der Ndh II (MOSHIRI et al, 1991;WU et al, 1997) SHINAGAWA et al, 1981;MATSUSHITA et al, 1994). BIZOUARN et al, 2002).…”

Section: Betrachtungen Zur Energiekonservierungunclassified

Entschlüsselung des Genoms von Gluconobacter oxydans 621H - einem Bakterium von industriellem Interesse

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Transcriptional regulation of cytochrome d in nitrogen-fixing Azotobacter vinelandii. Evidence that up-regulation during N2 fixation is independent of nifA but dependent on ntrA.

Cited by 28 publications

References 30 publications

Genetic determinants of ammonia excretion in nifL mutants of Azotobacter vinelandii

Genetic determinants of ammonia excretion in nifL mutants of Azotobacter vinelandii

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Entschlüsselung des Genoms von Gluconobacter oxydans 621H - einem Bakterium von industriellem Interesse

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