scholarly journals Role of Inosine Monophosphate Oxidoreductase in the Formation of Ureides in Nitrogen-Fixing Nodules of Cowpea (Vigna unguiculata L. Walp.)

1983 ◽  
Vol 72 (4) ◽  
pp. 1029-1034 ◽  
Author(s):  
Barry J. Shelp ◽  
Craig A. Atkins
Keyword(s):  
Vigna Unguiculata ◽  
Nitrogen Fixing ◽  
Inosine Monophosphate

scholarly journals Trees in agricultural and livestock development.

1985 ◽  
Vol 33 (2) ◽  
pp. 105-114 ◽  
Author(s):  
K.F. Wiersum
Keyword(s):  
Farming Systems ◽  
Nitrogen Fixing ◽  
Tree Management ◽  
Nitrogen Fixing Trees ◽  
Livestock Development

A review of the use of trees outside the forest in tropical farming systems: the role of trees; traditional systems of farm tree management; the scope for multipurpose (especially nitrogen-fixing) trees; wood yields from scattered or hedgerow trees and from woodlots; and development opportunities and programmes. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Novel Reiterated Fnr-Type Proteins Control the Production of the Symbiotic Terminal Oxidase cbb3 in Rhizobium etli CFN42

2007 ◽  
Vol 20 (10) ◽  
pp. 1241-1249 ◽  
Author(s):  
Manuel J. Granados-Baeza ◽  
Nicolás Gómez-Hernández ◽  
Yolanda Mora ◽  
María J. Delgado ◽  
David Romero ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Oxygen Affinity ◽  
Structural Similarity ◽  
Transcriptional Regulators ◽  
Terminal Oxidase ◽  
Nitrogen Fixing ◽  
Rhizobium Etli ◽  
High Oxygen Affinity ◽  
Key Genes

Symbiotic nitrogen-fixing bacteria express a terminal oxidase with a high oxygen affinity, the cbb3-type oxidase encoded by the fixNOQP operon. Previously, we have shown that, in Rhizobium etli CFN42, the repeated fixNOQP operons (fixNOQPd and fixNOQPf) have a differential role in nitrogen fixation. Only the fixNOQPd operon is required for the establishment of an effective symbiosis; microaerobic induction of this operon is under the control of at least three transcriptional regulators, FixKf, FnrNd, and FnrNchr, belonging to the Crp/Fnr family. In this work, we describe two novel Crp/Fnr-type transcriptional regulators (StoRd and StoRf, symbiotic terminal oxidase regulators) that play differential roles in the control of key genes for nitrogen fixation. Mutations either in stoRd or stoRf enhance the microaerobic expression of both fixNOQP reiterations, increasing also the synthesis of the cbb3-type oxidase in nodules. Despite their structural similarity, a differential role of these genes was also revealed, since a mutation in stoRd but not in stoRf enhanced both the expression of fixKf and the nitrogen-fixing capacity of R. etli CFN42.

Plasmid replicons of Rhizobium

2005 ◽  
Vol 33 (1) ◽  
pp. 157-158 ◽  
Author(s):  
L.C. Crossman
Keyword(s):  
Short Review ◽  
Nitrogen Fixing ◽  
Rhizobium Etli ◽  
Free Living ◽  
Leguminous Plants ◽  
Symbiotic Plasmid ◽  
Rhizobium Spp ◽  
Plasmid Replicons ◽  
Rhizobium Sp

Rhizobium spp. are found in soil. They are both free-living and found symbiotically associated with the nodules of leguminous plants. Traditionally, studies have focused on the association of these organisms with plants in nitrogen-fixing nodules, since this is regarded as the most important role of these bacteria in the environment. Rhizobium sp. are known to possess several replicons. Some, like the Rhizobium etli symbiotic plasmid p42d and the plasmid pNGR234b of Rhizobium NGR234, have been sequenced and characterized. The plasmids from these organisms are the focus of this short review.

scholarly journals Characterization and ecological role of free-living nitrogen-fixing bacteria isolated from the rhizoplane of Melastoma malabathricum inhabiting acidic plain lands in Kalimantan

Tropics ◽  
2006 ◽  
Vol 15 (4) ◽  
pp. 365-369 ◽  
Author(s):  
Yasuyuki HASHIDOKO ◽  
Yukako GOTOU ◽  
Mitsuru OSAKI ◽  
Erry PURNOMO ◽  
Limin H. SUWIDO ◽  
...  
Keyword(s):  
Ecological Role ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Free Living ◽  
Melastoma Malabathricum

scholarly journals A Dominant-Negative fur Mutation in Bradyrhizobium japonicum

2004 ◽  
Vol 186 (5) ◽  
pp. 1409-1414 ◽  
Author(s):  
Heather P. Benson ◽  
Kristin LeVier ◽  
Mary Lou Guerinot
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Iron Uptake ◽  
Outer Membrane Proteins ◽  
Dominant Negative ◽  
Ferric Uptake Regulator ◽  
Null Mutant ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Fur Protein

ABSTRACT In many bacteria, the ferric uptake regulator (Fur) protein plays a central role in the regulation of iron uptake genes. Because iron figures prominently in the agriculturally important symbiosis between soybean and its nitrogen-fixing endosymbiont Bradyrhizobium japonicum, we wanted to assess the role of Fur in the interaction. We identified a fur mutant by selecting for manganese resistance. Manganese interacts with the Fur protein and represses iron uptake genes. In the presence of high levels of manganese, bacteria with a wild-type copy of the fur gene repress iron uptake systems and starve for iron, whereas fur mutants fail to repress iron uptake systems and survive. The B. japonicum fur mutant, as expected, fails to repress iron-regulated outer membrane proteins in the presence of iron. Unexpectedly, a wild-type copy of the fur gene cannot complement the fur mutant. Expression of the fur mutant allele in wild-type cells leads to a fur phenotype. Unlike a B. japonicum fur-null mutant, the strain carrying the dominant-negative fur mutation is unable to form functional, nitrogen-fixing nodules on soybean, mung bean, or cowpea, suggesting a role for a Fur-regulated protein or proteins in the symbiosis.

The Role of Rhizobial Biodiversity in Legume Crop Productivity in the West Asian Highlands. IV. Rhizobium ciceri

1995 ◽  
Vol 31 (4) ◽  
pp. 501-507 ◽  
Author(s):  
J. D. H. Keatinge ◽  
D. P. Beck ◽  
L. A. Materon ◽  
N. Yurtsever ◽  
K. Karuc ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Research Priorities ◽  
Crop Productivity ◽  
Nitrogen Fixing ◽  
The West ◽  
Legume Crop

SUMMARYThe native rhizobia capable of symbiosis with chickpea crops in the Turkish highlands were surveyed and estimates made of the numbers of bacteria and the nitrogen fixing efficiency of isolates of R. ciceri in symbiosis with an improved Turkish cultivar and a local landracc. Soils were collected from locations at elevations between 500 and 2200 m.Native rhizobia specific to the local landrace were more abundant than those specific to the improved cultivar but nitrogen fixation efficiencies of all isolates were consistently poor. Agronomic research priorities must include the identification of strains of rhizobia symbiotically efficient and ecologically persistent in highland soils. Comprehensive trials with these strains as artificial inoculants on chickpeas are required throughout the region.Biodiversidad en el Rhizobium ciceri

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