LEGHEMOGLOBIN: THE ROLE OF HEMOGLOBIN IN THE NITROGEN-FIXING LEGUME ROOT NODULE

1975 ◽  
Vol 244 (1 The Biologica) ◽  
pp. 28-34 ◽  
Author(s):  
Jonathan B. Wittenberg ◽  
C. A. Appleby ◽  
F. J. Bergersen ◽  
G. L. Turner
Keyword(s):  
Root Nodule ◽  
Nitrogen Fixing

scholarly journals Involvement of Glutaredoxin and Thioredoxin Systems in the Nitrogen-Fixing Symbiosis between Legumes and Rhizobia

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 182 ◽  
Author(s):  
Geneviève Alloing ◽  
Karine Mandon ◽  
Eric Boncompagni ◽  
Françoise Montrichard ◽  
Pierre Frendo
Keyword(s):  
Sinorhizobium Meliloti ◽  
Root Nodule ◽  
Redox Balance ◽  
Atmospheric Nitrogen ◽  
Nitrogen Fixing ◽  
Symbiotic Interaction ◽  
Bacterial Differentiation ◽  
Genes Encoding ◽  
Transcriptomics Data

Leguminous plants can form a symbiotic relationship with Rhizobium bacteria, during which plants provide bacteria with carbohydrates and an environment appropriate to their metabolism, in return for fixed atmospheric nitrogen. The symbiotic interaction leads to the formation of a new organ, the root nodule, where a coordinated differentiation of plant cells and bacteria occurs. The establishment and functioning of nitrogen-fixing symbiosis involves a redox control important for both the plant-bacteria crosstalk and the regulation of nodule metabolism. In this review, we discuss the involvement of thioredoxin and glutaredoxin systems in the two symbiotic partners during symbiosis. The crucial role of glutathione in redox balance and S-metabolism is presented. We also highlight the specific role of some thioredoxin and glutaredoxin systems in bacterial differentiation. Transcriptomics data concerning genes encoding components and targets of thioredoxin and glutaredoxin systems in connection with the developmental step of the nodule are also considered in the model system Medicago truncatula–Sinorhizobium meliloti.

scholarly journals Root nodule symbiosis in Lotus japonicus drives the establishment of distinctive rhizosphere, root, and nodule bacterial communities

2016 ◽  
Vol 113 (49) ◽  
pp. E7996-E8005 ◽  
Author(s):  
Rafal Zgadzaj ◽  
Ruben Garrido-Oter ◽  
Dorthe Bodker Jensen ◽  
Anna Koprivova ◽  
Paul Schulze-Lefert ◽  
...  
Keyword(s):  
Community Structure ◽  
Plant Growth ◽  
Root Nodule ◽  
Lotus Japonicus ◽  
Direct Consequence ◽  
Rrna Gene ◽  
Nitrogen Fixing ◽  
Model Legume ◽  
Symbiotic Relationships

Lotus japonicus has been used for decades as a model legume to study the establishment of binary symbiotic relationships with nitrogen-fixing rhizobia that trigger root nodule organogenesis for bacterial accommodation. Using community profiling of 16S rRNA gene amplicons, we reveal that in Lotus, distinctive nodule- and root-inhabiting communities are established by parallel, rather than consecutive, selection of bacteria from the rhizosphere and root compartments. Comparative analyses of wild-type (WT) and symbiotic mutants in Nod factor receptor5 (nfr5), Nodule inception (nin) and Lotus histidine kinase1 (lhk1) genes identified a previously unsuspected role of the nodulation pathway in the establishment of different bacterial assemblages in the root and rhizosphere. We found that the loss of nitrogen-fixing symbiosis dramatically alters community structure in the latter two compartments, affecting at least 14 bacterial orders. The differential plant growth phenotypes seen between WT and the symbiotic mutants in nonsupplemented soil were retained under nitrogen-supplemented conditions that blocked the formation of functional nodules in WT, whereas the symbiosis-impaired mutants maintain an altered community structure in the nitrogen-supplemented soil. This finding provides strong evidence that the root-associated community shift in the symbiotic mutants is a direct consequence of the disabled symbiosis pathway rather than an indirect effect resulting from abolished symbiotic nitrogen fixation. Our findings imply a role of the legume host in selecting a broad taxonomic range of root-associated bacteria that, in addition to rhizobia, likely contribute to plant growth and ecological performance.

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.

Role of rhizobial lipo-chitin oligosaccharide signal molecules in root nodule organogenesis

1994 ◽  
Vol 26 (5) ◽  
pp. 1413-1422 ◽  
Author(s):  
Herman P. Spaink ◽  
Ben J. J. Lugtenberg
Keyword(s):  
Root Nodule ◽  
Signal Molecules

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.

Dryland legumes: perspectives and problems

2003 ◽  
Vol 11 ◽  
pp. 27-36
Author(s):  
D. Scott
Keyword(s):  
Root Nodule ◽  
Fine Root ◽  
Animal Feed ◽  
Environmental Gradients ◽  
N Fixation ◽  
Indigenous Species ◽  
Nodule Bacteria ◽  
Pastoral Systems ◽  
Fertility Gradient

The different perspectives or concepts involved in developing legumes for dryland pastoral systems is commented on in relation to: N-fixation versus animal feed; root nodule bacteria requirements; large introduced legume flora compared with indigenous; species niche in relation to environmental gradients of moisture, temperature, fertility, and grazing; species adaptation along the decreasing fertility gradient from fine-root nutrient scavenging grasses, N-fixers, mycorrhiza, and proteoid roots; interaction of N- fixation with soil organic matter; establishment; determinants of pastures legume composition; and the possible role of allelopathy. Key words: dryland, environmental gradients, legumes, N-fixation, pasture composition

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 New Species of Devosia That Forms a Unique Nitrogen-Fixing Root-Nodule Symbiosis with the Aquatic Legume Neptunia natans (L.f.) Druce

2002 ◽  
Vol 68 (11) ◽  
pp. 5217-5222 ◽  
Author(s):  
Raul Rivas ◽  
Encarna Velázquez ◽  
Anne Willems ◽  
Nieves Vizcaíno ◽  
Nanjappa S. Subba-Rao ◽  
...  
Keyword(s):  
Root Nodule ◽  
Root Nodules ◽  
Infection Process ◽  
Nitrogen Fixing ◽  
Rhizobium Tropici ◽  
Rdna Sequences ◽  
Root Nodule Symbiosis ◽  
16S Rdna Sequences ◽  
The Common ◽  
Nodule Symbiosis

ABSTRACT Rhizobia are the common bacterial symbionts that form nitrogen-fixing root nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in African soils is nodulated by Allorhizobium undicola. This legume develops an unusual root-nodule symbiosis on floating stems in aquatic environments through a unique infection process. Here, we analyzed the low-molecular-weight RNA and 16S ribosomal DNA (rDNA) sequence of the same fast-growing isolates from India that were previously used to define the developmental morphology of the unique infection process in this symbiosis with N. natans and found that they are phylogenetically located in the genus Devosia, not Allorhizobium or Rhizobium. The 16S rDNA sequences of these two Neptunia-nodulating Devosia strains differ from the only species currently described in that genus, Devosia riboflavina. From the same isolated colonies, we also located their nodD and nifH genes involved in nodulation and nitrogen fixation on a plasmid of approximately 170 kb. Sequence analysis showed that their nodD and nifH genes are most closely related to nodD and nifH of Rhizobium tropici, suggesting that this newly described Neptunia-nodulating Devosia species may have acquired these symbiotic genes by horizontal transfer.

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