A spontaneous chlorate-resistant mutant of Azospirillum brasilense Sp245 displays defects in nitrate reduction and plant root colonization

2001 ◽  
Vol 33 (4) ◽  
pp. 317-322 ◽  
Author(s):  
Oda Steenhoudt ◽  
Zhu Ping ◽  
Ann Vande Broek ◽  
Jos Vanderleyden
Keyword(s):  
Nitrate Reduction ◽  
Azospirillum Brasilense ◽  
Root Colonization ◽  
Plant Root ◽  
Resistant Mutant ◽  
Chlorate Resistant Mutant

scholarly journals Nitrate reduction mutants of fusarium moniliforme (gibberella fujikuroi).

Genetics ◽  
1988 ◽  
Vol 118 (3) ◽  
pp. 417-423
Author(s):  
C Klittich ◽  
J F Leslie
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Fusarium Moniliforme ◽  
Reductase Activity ◽  
Regulatory Gene ◽  
Resistant Mutant ◽  
Gibberella Fujikuroi ◽  
Mutant Type ◽  
Nit Mutants ◽  
Chlorate Resistant Mutant

Abstract Twelve strains of Fusarium moniliforme were examined for their ability to sector spontaneously on toxic chlorate medium. All strains sectored frequently; 91% of over 1200 colonies examined formed chlorate-resistant, mutant sectors. Most of these mutants had lesions in the nitrate reduction pathway and were unable to utilize nitrate (nit mutants). nit mutations occurred in seven loci: a structural gene for nitrate reductase (nit1), a regulatory gene specific for the nitrate reduction pathway (nit3), and five genes controlling the production of a molybdenum-containing cofactor that is necessary for nitrate reductase activity (nit2, nit4, nit5, nit6, nit7). No mutations affecting nitrite reductase or a major nitrogen regulatory locus were found among over 1000 nit mutants. Mutations of nit1 were recovered most frequently (39-66%, depending on the strain) followed by nit3 mutations (23-42%). The frequency of isolation of each mutant type could be altered, however, by changing the source of nitrogen in the chlorate medium. We concluded that genetic control of nitrate reduction in F. moniliforme is similar to that in Aspergillus and Neurospora, but that the overall regulation of nitrogen metabolism may be different.

scholarly journals Deletion of Rap‐Phr systems in Bacillus subtilis influences in vitro biofilm formation and plant root colonization

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Mathilde Nordgaard ◽  
Rasmus Møller Rosenbek Mortensen ◽  
Nikolaj Kaae Kirk ◽  
Ramses Gallegos‐Monterrosa ◽  
Ákos T. Kovács
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Root Colonization ◽  
Plant Root

Molybdenum incorporation in denitrifying Azospirillum brasilense Sp7

1992 ◽  
Vol 38 (10) ◽  
pp. 1042-1047 ◽  
Author(s):  
Christian Chauret ◽  
Wilfredo L. Barraquio ◽  
Roger Knowles
Keyword(s):  
Nitrate Reductase ◽  
Key Words ◽  
Nitrate Reduction ◽  
Gel Electrophoresis ◽  
Azospirillum Brasilense ◽  
Paracoccus Denitrificans ◽  
Free Medium ◽  
Azospirillum Brasilense Sp7

Nondenaturating disc gel electrophoresis revealed that 99Mo was incorporated into the nitrate reductase of Azospirillum brasilense grown in the absence but not in the presence of tungstate. Under denitrifying conditions, A. brasilense grown in tungsten-free medium steadily accumulated 99Mo for 12 h. In contrast, Paracoccus denitrificans grown under the same conditions ceased uptake after 1 h. However, both bacteria were incapable of accumulating significant amounts of 99Mo in media containing 10 mM tungstate, even though nitrate was reduced by A. brasilense. Aerobically grown A. brasilense cells transported 99Mo more efficiently than anaerobically grown cells. Key words: Azospirillum brasilense, tungsten, molybdenum incorporation, nitrate reduction.

scholarly journals Microfluidics: Quantifying the Spatiotemporal Dynamics of Plant Root Colonization by Beneficial Bacteria in a Microfluidic Habitat (Adv. Biosys. 6/2018)

2018 ◽  
Vol 2 (6) ◽  
pp. 1870051 ◽  
Author(s):  
Jayde A. Aufrecht ◽  
Collin M. Timm ◽  
Amber Bible ◽  
Jennifer L. Morrell-Falvey ◽  
Dale A. Pelletier ◽  
...  
Keyword(s):  
Root Colonization ◽  
Plant Root ◽  
Spatiotemporal Dynamics ◽  
Beneficial Bacteria

Nitrogen Fixation and Nitrate Respiration by A zospirillum brasilense

1983 ◽  
Vol 38 (7-8) ◽  
pp. 571-577 ◽  
Author(s):  
Hermann Bothe ◽  
Gislene Barbosa ◽  
Johanna Dobereiner
Keyword(s):  
Nitrogen Fixation ◽  
Nitrate Reduction ◽  
Azospirillum Brasilense ◽  
Nitrate Respiration ◽  
Present Communication ◽  
Reaction Proceeding ◽  
Physiological Properties ◽  
Assimilatory Nitrate Reduction

The O2- sensitivitiy of N2-fixation by the carotenoid forming strain Azospirillum brasilense Cd and the colourless strain Sp 7 is compared in the present communication. As no difference in the reaction is observed with both strains, it is concluded that carotenoids do not protect nitrogenase from damage by O2. Azospirillum spp. have also been shown to perform NO3-- dependent N2-fixation. The physiological properties of this reaction are described in more detail in the present communication. Evidence is presented that NO3-- dependent N2-fixation is a transitory reaction, proceeding only as long as the enzymes of assimilatory nitrate reduction are synthesized by the cells.

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