scholarly journals Rhizobium tropici Genes Involved in Free-Living Salt Tolerance are Required for the Establishment of Efficient Nitrogen-Fixing Symbiosis with Phaseolus vulgaris

2002 ◽  
Vol 15 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Joaquina Nogales ◽  
Rosario Campos ◽  
Hanaa BenAbdelkhalek ◽  
José Olivares ◽  
Carmen Lluch ◽  
...  

Characterization of nine transposon-induced mutants of Rhizobium tropici with decreased salt tolerance (DST) allowed the identification of eight gene loci required for adaptation to high external NaCl. Most of the genes also were involved in adaptation to hyperosmotic media and were required to overcome the toxicity of LiCl. According to their possible functions, genes identified could be classified into three groups. The first group included two genes involved in regulation of gene expression, such as ntrY, the sensor element of the bacterial ntrY/ntrX two-component regulatory system involved in regulation of nitrogen metabolism, and greA, which encodes a transcription elongation factor. The second group included genes related to synthesis, assembly, or maturation of proteins, such as alaS coding for alanine-tRNA synthetase, dnaJ, which encodes a molecular chaperone, and a nifS homolog probably encoding a cysteine desulfurase involved in the maturation of Fe-S proteins. Genes related with cellular build-up and maintenance were in the third group, such as a noeJ-homolog, encoding a mannose-1-phosphate guanylyltransferase likely involved in lipopolysaccharide biosynthesis, and kup, specifying an inner-membrane protein involved in potassium uptake. Another gene was identified that had no homology to known genes but that could be conserved in other rhizobia. When inoculated on Phaseolus vulgaris growing under nonsaline conditions, all DST mutants displayed severe symbiotic defects: ntrY and noeJ mutants were impaired in nodulation, and the remaining mutants formed symbiosis with very reduced nitrogenase activity. The results suggest that bacterial ability to adapt to hyper-osmotic and salt stress is important for the bacteroid nitrogen-fixing function inside the legume nodule and provide genetic evidence supporting the suggestion that rhizobia face severe environmental changes after their release into plant cells.

2008 ◽  
Vol 51 (6) ◽  
pp. 1089-1096 ◽  
Author(s):  
João Francisco Berton Junior ◽  
Julio Cesar Pires Santos ◽  
Cileide Maria Medeiros Coelho ◽  
Osmar Klauberg Filho

The objective of this work was to evaluate the efficiency of nitrogen fixing inoculum associated with Co + Mo leaf spray on the common bean grain yield and grain nutrients, cv. FT Nobre. Three dosages of the inoculant (0, 200 and 400 g/50 kg seeds), combined with four Co + Mo leaf spray levels (T0=0,0; T1=4.9,49; T2=7.3,73; and T3=9.7,97 g ha-1 of Co and Mo, respectively) were tested. The grain yield with the use of the inoculant (400 g / 5O kg seed-1) associated with the higher level of Co+Mo (T2 and T3) was very similar to the mineral nitrogen condition fertilizer recommended for the bean (70 kg ha-1 of N). With the increased inoculant dosage, an increase of the protein content and of P and Mg in the grain was also observed. The results indicated that the mineral nitrogen source could be replaced by inoculation of the seeds with Rhizobium tropici combined with Co + Mo leaf spray.


2000 ◽  
Vol 42 (5-6) ◽  
pp. 407-410 ◽  
Author(s):  
J. Pérez-Vargas ◽  
H.M. Poggi-Varaldo ◽  
G. Calva-Calva ◽  
E. Ríos-Leal ◽  
R. Rodríguez-Vázquez ◽  
...  

Several nitrogen fixing consortia (NFC) were isolated from kerosene contaminated soil, where Phaseolus vulgaris plants were being cultivated. The capability of these consortia for kerosene hydrocarbons removal was investigated and demonstrated. The NFC cultivated under aerobic conditions, and kerosene as sole carbon source, effected a maximum of 75% of reduction of the total kerosene hydrocarbons. Also, from experiments conducted to evaluate their atmospheric nitrogen fixing capability, all consortia showed nitrogenase activity: from 4 to 183 nmol N2/3E09 bacteria.day. To our knowledge, this is the first report that shows a group of bacteria with the dual characteristic of fixing atmospheric nitrogen and capability to use kerosene hydrocarbons as a sole carbon source. Application of these microorganisms to soil bioremediation processes is discussed.


2001 ◽  
Vol 67 (7) ◽  
pp. 3264-3268 ◽  
Author(s):  
M. Antonio Rogel ◽  
Ismael Hern�ndez-Lucas ◽  
L. David Kuykendall ◽  
David L. Balkwill ◽  
Esperanza Martinez-Romero

ABSTRACT Ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause lysis of these other bacteria. Based on the sequence of its small-subunit rRNA gene, E. adhaerensis related to Sinorhizobium spp. E. adhaerensATCC 33499 did not nodulate Phaseolus vulgaris (bean) orLeucaena leucocephala, but with symbiotic plasmids fromRhizobium tropici CFN299 it formed nitrogen-fixing nodules on both hosts. The nodule isolates were identified as E. adhaerens isolates by growth on selective media.


2016 ◽  
Vol 404 (1-2) ◽  
pp. 413-425 ◽  
Author(s):  
Miguel López-Gómez ◽  
Libertad Cobos-Porras ◽  
Jürgen Prell ◽  
Carmen Lluch

2019 ◽  
Vol 8 (9) ◽  
Author(s):  
Luis E. Servín-Garcidueñas ◽  
Gabriela Guerrero ◽  
Marco A. Rogel-Hernández ◽  
Esperanza Martínez-Romero

We present the genome sequence of Rhizobium jaguaris CCGE525T, a nitrogen-fixing bacterium isolated from nodules of Calliandra grandiflora. CCGE525T belongs to Rhizobium tropici group A, represents the symbiovar calliandrae, and forms nitrogen-fixing nodules in Phaseolus vulgaris.


2020 ◽  
Vol 477 (16) ◽  
pp. 3091-3104 ◽  
Author(s):  
Luciana E. Giono ◽  
Alberto R. Kornblihtt

Gene expression is an intricately regulated process that is at the basis of cell differentiation, the maintenance of cell identity and the cellular responses to environmental changes. Alternative splicing, the process by which multiple functionally distinct transcripts are generated from a single gene, is one of the main mechanisms that contribute to expand the coding capacity of genomes and help explain the level of complexity achieved by higher organisms. Eukaryotic transcription is subject to multiple layers of regulation both intrinsic — such as promoter structure — and dynamic, allowing the cell to respond to internal and external signals. Similarly, alternative splicing choices are affected by all of these aspects, mainly through the regulation of transcription elongation, making it a regulatory knob on a par with the regulation of gene expression levels. This review aims to recapitulate some of the history and stepping-stones that led to the paradigms held today about transcription and splicing regulation, with major focus on transcription elongation and its effect on alternative splicing.


2020 ◽  
Vol 27 ◽  
Author(s):  
Neelja Singhal ◽  
Archana Sharma ◽  
Manisha Aswal ◽  
Nirpendra Singh ◽  
Manish Kumar ◽  
...  

Background:: CsaA is among the few chaperones which are present in both bacteria and archaea, but absent in eukaryotes. There are no reports on interactome analysis of CsaA from archaea, till date. Identification of binding partners of CsaA might be helpful in understanding CsaA-associated processes in Picrophilus torridus– an extreme thermoaci-dophilic euryarchaeon. Objectives:: The present study was conducted to identify the binding partners of CsaA of P. torridus (PtCsaA). Methods:: The binding partners of PtCsaA were isolated and identified using a pull down assay and liquid chromatography-mass spectrometry (LC-MS). Results:: The results revealed twelve potential binding partners of CsaA. These were thermosome subunits (Q6KZS2 and Q6L132), nascent polypeptide-associated complex protein (Q6L1N3), elongation factor 1-alpha (Q6L202), uncharacterized protein (Q6L0Y6), citrate synthase (Q6L0M8), asparaginyl-tRNA synthetase (Q6L0M5), succinyl-CoA synthetase beta chain (Q6L0B4), pyruvate ferredoxin oxidoreductase alpha and beta chain proteins (Q6KZA7 and Q6KZA6, respectively), malate dehydrogenase (Q6L0C3) and reversed fumarylacetoacetase (Q6KZ97). Functional categorization revealed that of these, six proteins were involved in energy metabolic pathways, three were archaeal chaperones, two were involved in trans-lation and one might be a transcription regulator. STRING-based analysis of the protein-protein interactions of the experi-mental interactome revealed strong interactions among them. Conclusion:: PtCsaA might be a multifaceted protein which besides translation might also play important role in metabolic processes of P. torridus. However, further experiments investigating the binding partners of CsaA in other archaea are re-quired for a better understanding of CsaA-associated processes in archaea.


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