The role of biological nitrogen fixation research in solving problems in tropical agriculture

1988 ◽  
Vol 108 (1) ◽  
pp. 15-21 ◽  
Author(s):  
E. F. Henzell
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Tropical Agriculture ◽  
Biological Nitrogen

scholarly journals The Significance of Flavonoids in the Process of Biological Nitrogen Fixation

2020 ◽  
Vol 21 (16) ◽  
pp. 5926
Author(s):  
Wei Dong ◽  
Yuguang Song
Keyword(s):  
Nitrogen Fixation ◽  
Plant Species ◽  
Biological Nitrogen Fixation ◽  
Molecular Basis ◽  
Phenylpropanoid Pathway ◽  
Rhizobium Spp ◽  
Microbial Symbionts ◽  
Biological Nitrogen ◽  
Do So

Nitrogen is essential for the growth of plants. The ability of some plant species to obtain all or part of their requirement for nitrogen by interacting with microbial symbionts has conferred a major competitive advantage over those plants unable to do so. The function of certain flavonoids (a group of secondary metabolites produced by the plant phenylpropanoid pathway) within the process of biological nitrogen fixation carried out by Rhizobium spp. has been thoroughly researched. However, their significance to biological nitrogen fixation carried out during the actinorhizal and arbuscular mycorrhiza–Rhizobium–legume interaction remains unclear. This review catalogs and contextualizes the role of flavonoids in the three major types of root endosymbiosis responsible for biological nitrogen fixation. The importance of gaining an understanding of the molecular basis of endosymbiosis signaling, as well as the potential of and challenges facing modifying flavonoids either quantitatively and/or qualitatively are discussed, along with proposed strategies for both optimizing the process of nodulation and widening the plant species base, which can support nodulation.

scholarly journals Role of Diazotrophic Bacteria in Biological Nitrogen Fixation and Plant Growth Improvement

2016 ◽  
Vol 49 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Wansik Shin ◽  
Rashedul Islam ◽  
Abitha Benson ◽  
Manoharan Melvin Joe ◽  
Kiyoon Kim ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Biological Nitrogen Fixation ◽  
Diazotrophic Bacteria ◽  
Biological Nitrogen

scholarly journals Proteome Profiling of the Rhodobacter capsulatus Molybdenum Response Reveals a Role of IscN in Nitrogen Fixation by Fe-Nitrogenase

2015 ◽  
Vol 198 (4) ◽  
pp. 633-643 ◽  
Author(s):  
Marie-Christine Hoffmann ◽  
Eva Wagner ◽  
Sina Langklotz ◽  
Yvonne Pfänder ◽  
Sina Hött ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Rhodobacter Capsulatus ◽  
Nitrogenase Activity ◽  
Central Process ◽  
Content Type ◽  
Proteome Profiling ◽  
Biological Nitrogen ◽  
Diazotrophic Growth

ABSTRACTRhodobacter capsulatusis capable of synthesizing two nitrogenases, a molybdenum-dependent nitrogenase and an alternative Mo-free iron-only nitrogenase, enabling this diazotroph to grow with molecular dinitrogen (N2) as the sole nitrogen source. Here, the Mo responses of the wild type and of a mutant lacking ModABC, the high-affinity molybdate transporter, were examined by proteome profiling, Western analysis, epitope tagging, andlacZreporter fusions. Many Mo-controlled proteins identified in this study have documented or presumed roles in nitrogen fixation, demonstrating the relevance of Mo control in this highly ATP-demanding process. The levels of Mo-nitrogenase, NifHDK, and the Mo storage protein, Mop, increased with increasing Mo concentrations. In contrast, Fe-nitrogenase, AnfHDGK, and ModABC, the Mo transporter, were expressed only under Mo-limiting conditions. IscN was identified as a novel Mo-repressed protein. Mo control of Mop, AnfHDGK, and ModABC corresponded to transcriptional regulation of their genes by the Mo-responsive regulators MopA and MopB. Mo control of NifHDK and IscN appeared to be more complex, involving different posttranscriptional mechanisms. In line with the simultaneous control of IscN and Fe-nitrogenase by Mo, IscN was found to be important for Fe-nitrogenase-dependent diazotrophic growth. The possible role of IscN as an A-type carrier providing Fe-nitrogenase with Fe-S clusters is discussed.IMPORTANCEBiological nitrogen fixation is a central process in the global nitrogen cycle by which the abundant but chemically inert dinitrogen (N2) is reduced to ammonia (NH3), a bioavailable form of nitrogen. Nitrogen reduction is catalyzed by nitrogenases found in diazotrophic bacteria and archaea but not in eukaryotes. All diazotrophs synthesize molybdenum-dependent nitrogenases. In addition, some diazotrophs, includingRhodobacter capsulatus, possess catalytically less efficient alternative Mo-free nitrogenases, whose expression is repressed by Mo. Despite the importance of Mo in biological nitrogen fixation, this is the first study analyzing the proteome-wide Mo response in a diazotroph. IscN was recognized as a novel member of the molybdoproteome inR. capsulatus. It was dispensable for Mo-nitrogenase activity but supported diazotrophic growth under Mo-limiting conditions.

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