Nitrogen-fixing bacteria associated with plantation and orchard plants

1983 ◽  
Vol 29 (8) ◽  
pp. 863-866 ◽  
Author(s):  
N. S. Subba Rao
Keyword(s):  
Rhizosphere Soil ◽  
Bacterial Isolates ◽  
Nitrogen Fixing ◽  
Triphenyltetrazolium Chloride ◽  
Nitrogen Fixing Bacteria ◽  
Cortical Cells ◽  
Pure Cultures ◽  
Free Media ◽  
Motile Bacteria

Rhizosphere soil of several plantation and orchard plants were analyzed to enumerate and isolate Azotobacter and Beijerinckia. Azospirillum was isolated from washed and surface-sterilized roots and 14 of the isolates were classified as A. lipoferum or A. brasilense. The ability of all these bacterial isolates to fix N2 in pure cultures on N-free media was established by Microkjeldahl and C2H2 reduction procedures. Motile bacteria capable of reducing triphenyltetrazolium chloride were found to be more abundant in xylem cells than in cortical cells of roots.

Research on Improvement of Nitrogenase Activity of Free-Living Nitrogen-Fixing Bacteria Using DBD Plasma

2013 ◽  
Vol 671-674 ◽  
pp. 2674-2678 ◽  
Author(s):  
Yan Yun Zhu ◽  
Xiao Li Zhu ◽  
Fang She Yang
Keyword(s):  
Rhizosphere Soil ◽  
Barrier Discharge ◽  
Nitrogenase Activity ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Dbd Plasma ◽  
Nitrogen Fixing Bacteria ◽  
Free Living ◽  
Reduction Assay ◽  
Rrna Sequencing

Nitrogen-fixing bacteria were screened from the rhizosphere soil of plants in Shaanxi in China. 36 free-living nitrogen-fixing bacterial strains were isolated and their nitrogenase activity were determined by acetylene reduction assay (ARA), two strains named FLNB03 and FLNB09 with higher nitrogenase activity were isolated and identified by 16S rRNA sequencing. The datum showed that FLNB03 was similar to Acinetobacter and their similarity reached 99%, FLNB09 was similar to Agrobacterium sp. and their similarity reached 99%. Then both of them were treated using Dielectric Barrier Discharge (DBD) plasma for mutation and their mutants called FLNB03-2 and FLNB09-3 were obtained. The nitrogenase activity of FLNB03-2 was 0.61±0.10 nmol•107cfu-1•h-1, and that of FLNB09-3 was 0.40±0.05 nmol•107cfu-1•h-1, their nitrogenase activity increased by 22.00% and 14.29% than their original bacteria respectively. FLNB03-2 and FLNB09-3 might be used as microbial fertilizer.

Phylogenetic diversity of nitrogen-fixing bacteria and thenifHgene from mangrove rhizosphere soil

2012 ◽  
Vol 58 (4) ◽  
pp. 531-539 ◽  
Author(s):  
Jianyin Liu ◽  
Mengjun Peng ◽  
Youguo Li
Keyword(s):  
Phylogenetic Trees ◽  
Rhizosphere Soil ◽  
Nifh Gene ◽  
Soil Samples ◽  
Community Diversity ◽  
Nitrogen Fixing ◽  
Pcr Cloning ◽  
Nitrogen Fixing Bacteria ◽  
Soil Dna ◽  
Mangrove Ecosystems

Nine types of nitrogen-fixing bacterial strains were isolated from 3 rhizosphere soil samples taken from mangrove plants in the Dongzhaigang National Mangrove Nature Reserve of China. Most isolates belonged to Gammaproteobacteria Pseudomonas , showing that these environments constituted favorable niches for such abundant nitrogen-fixing bacteria. New members of the diazotrophs were also found. Using a soil DNA extraction and PCR-cloning-sequencing approach, 135 clones were analyzed by restriction fragment length polymorphism (RFLP) analysis, and 27 unique nifH sequence phylotypes were identified, most of which were closely related to sequences from uncultured bacteria. The diversity of nitrogen-fixing bacteria was assessed by constructing nifH phylogenetic trees from sequences of all isolates and clones in this work, together with related nifH sequences from other mangrove ecosystems in GenBank. The nifH diversity varied among soil samples, with distinct biogeochemical properties within a mangrove ecosystem. When comparing different mangrove ecosystems, the nifH gene sequences from a specific site tended to cluster as individual groups. The results provided interesting data and novel information on our understanding of diazotroph community diversity in the mangrove ecosystems.

scholarly journals Genomic characterization and computational phenotyping of nitrogen-fixing bacteria isolated from Colombian sugarcane fields

2019 ◽  
Author(s):  
Luz K. Medina-Cordoba ◽  
Aroon T. Chande ◽  
Lavanya Rishishwar ◽  
Leonard W. Mayer ◽  
Lina C. Valderrama-Aguirre ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Nitrogen Fixation ◽  
Plant Growth ◽  
Phosphate Solubilization ◽  
Bacterial Isolates ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
A Genome ◽  
Plant Growth Promoting ◽  
Growth Promoting

ABSTRACTPrevious studies have shown that the sugarcane microbiome harbors diverse plant growth promoting (PGP) microorganisms, including nitrogen-fixing bacteria, and the objective of this study was to design a genome-enabled approach to prioritize sugarcane associated nitrogen-fixing bacteria according to their potential as biofertilizers. Using a systematic high throughput approach, 22 pure cultures of nitrogen-fixing bacteria were isolated and tested for diazotrophic potential by PCR amplification of nitrogenase (nifH) genes, common molecular markers for nitrogen fixation capacity. Genome sequencing confirmed the presence of intact nitrogenase nifH genes and operons in the genomes of 18 of the isolates. Isolate genomes also encoded operons for phosphate solubilization, siderophore production operons, and other PGP phenotypes. Klebsiella pneumoniae strains comprised 14 of the 22 nitrogen-fixing isolates, and four others were members of closely related genera to Klebsiella. A computational phenotyping approach was developed to rapidly screen for strains that have high potential for nitrogen fixation and other PGP phenotypes while showing low risk for virulence and antibiotic resistance. The majority of sugarcane isolates were below a genotypic and phenotypic threshold, showing uniformly low predicted virulence and antibiotic resistance compared to clinical isolates. Six prioritized strains were experimentally evaluated for PGP phenotypes: nitrogen fixation, phosphate solubilization, and the production of siderophores, gibberellic acid and indole acetic acid. Results from the biochemical assays were consistent with the computational phenotype predictions for these isolates. Our results indicate that computational phenotyping is a promising tool for the assessment of benefits and risks associated with bacteria commonly detected in agricultural ecosystems.IMPORTANCEA genome-enabled approach was developed for the prioritization of native bacterial isolates with the potential to serve as biofertilizers for sugarcane fields in Colombia’s Cauca Valley. The approach is based on computational phenotyping, which entails predictions related to traits of interest based on bioinformatic analysis of whole genome sequences. Bioinformatic predictions of the presence of plant growth promoting traits were validated with experimental assays and more extensive genome comparisons, thereby demonstrating the utility of computational phenotyping for assessing the benefits and risks posed by bacterial isolates that can be used as biofertilizers. The quantitative approach to computational phenotyping developed here for the discovery of biofertilizers has the potential for use with a broad range of applications in environmental and industrial microbiology, food safety, water quality, and antibiotic resistance studies.

A Survey of Asymbiotic Nitrogen Fixation in the Rhizosphere of Weeds

Weed Science ◽  
1978 ◽  
Vol 26 (2) ◽  
pp. 148-150 ◽  
Author(s):  
A. R. Conklin ◽  
P. K. Biswas
Keyword(s):  
Thin Film ◽  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Rhizosphere Soil ◽  
Soil Samples ◽  
Reduction Technique ◽  
Nitrogen Fixing ◽  
Weed Species ◽  
Nitrogen Fixing Bacteria ◽  
Asymbiotic Nitrogen Fixation

The occurrence of asymbiotic nitrogen fixing bacteria in the rhizosphere of twenty weed species has been investigated. Using the roll tube method root-rhizosphere soil samples were diluted and added to test tubes containing low N media. Tubes were flushed with nitrogen, stoppered, and rolled to form a thin film of media on the inner wall. After 7 days incubation the nitrogen fixation rates were estimated using the acetylene reduction technique. Rates ranged from 38 to 783 nmoles acetylene reduced per hour. Of twenty species tested, three showed high rhizosphere populations of asymbiotic nitrogen fixing bacteria.

scholarly journals The assimilation of nitrogen by certain nitrogen-fixing bacteria in the soil

1910 ◽  
Vol 82 (560) ◽  
pp. 627-629 ◽  
Keyword(s):  
Soil Nitrogen ◽  
Growth And Development ◽  
Potassium Phosphate ◽  
Garden Soil ◽  
Culture Solution ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Negative Results ◽  
Sodium Hydrate ◽  
Pure Cultures

In a communication on “Some Effects of Nitrogen-fixing Bacteria on the Growth of Non-Leguminous Plants,” it was pointed out that Azotobcider and Pseudomonas obtained from the root tubercles of Cycas when grown together fix more nitrogen per unit of carbohydrate than the combined amount of nitrogen when each is grown separately. In order to determine if this is true for a mixed culture of Azotobacter and Pseudomonas obtained from ordinary soil and leguminous nodules respectively, pure cultures of these organisms were obtained, Azotobacter and chroocoecm from garden soil and Pseudomonas radicicola from bean and clover nodules, by the method already described. Erlenmeyer flasks containing a culture solution, consisting of maltose 0·5 gramme, mannite 0·5 gramme, monobasic potassium phosphate 0·1 gramme, magnesium sulphate 0·02 gramme, in 100 c.c. distilled water and rendered neutral by sodium hydrate, were inoculated with 1 c.c. of pure cultures per 100 c.c. of culture solution (the controls being autoclaved to kill the bacteria present), and incubated at 24° C. for 10 days. Nitrogen determinations of the contents of the flasks gave the following averages:- Gerlaeh, Lipman, and others have described experiments showing that pure cultures of Azotobader and Pseudomonas respectively have little or no power to increase the store of soil nitrogen when added directly to the soil. A probable explanation of these negative results may be found in the different conditions for growth and development in ordinary soil and in a culture solution.

Use of Pankhurst tubes to assay acetylene reduction by facultative and anaerobic nitrogen-fixing bacteria

1969 ◽  
Vol 15 (11) ◽  
pp. 1342-1343 ◽  
Author(s):  
N. E. R. Campbell ◽  
Harold J. Evans
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Most Probable Number ◽  
Bacterial Isolates ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Probable Number ◽  
Density Measurements ◽  
Large Numbers ◽  
Root Surfaces

Pankhurst tubes are simple and inexpensive vessels in which to screen large numbers of bacterial isolates by the acetylene reduction test for nitrogen fixation. A modification is described which allows, in addition, optical density measurements of growth. The method is well suited to most probable number estimations of facultative and anaerobic nitrogen-fixing bacteria in soils and on root surfaces.

scholarly journals PRODUCTION OF PHYTOHORMONES OF BRADYRHIZOBIUM JAPONICUM AND AZOSPIRILLUM BRASILENSE UNDER THEIR SIMULTANEOUS CULTIVATION

2018 ◽  
Vol 28 ◽  
pp. 33-40
Author(s):  
S.F. Kozar
Keyword(s):  
Abscisic Acid ◽  
Mixed Culture ◽  
Pure Culture ◽  
Bradyrhizobium Japonicum ◽  
Azospirillum Brasilense ◽  
Culture Fluid ◽  
Culture Liquid ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Pure Cultures

Objective. Investigate the activity of biosynthesis of phytohormonal substances with nitrogen-fixing bacteria Bradyrhizobium japonicum and Azospirillum brasilense in pure and mixed culture. Methods. Microbiological, chromatographic, and mathematical. Results It has been established that the simultaneous cultivation of B. japonicum M-8 and A. brasilense 410 increases the content of gibberellins and cytokinins in the culture fluid of the test microorganisms. The content of gibberellic acid and isopentenylidene has increased most intensively in mixed culture compared with the pure culture of rhizobia. In the course of co-cultivation, the studied diazotrophs more intensively produced auxins compared to soybean rhizobia in pure culture, but less compared to pure culture of azospirilla. The highest level of abscisic acid that can inhibit the formation of nodules was found in A. brasilense 410 culture fluid, and it was lower when cultivating B japonicum M-8. However, the smallest amount of this phytohormone was found in the culture liquid of diazotrophs under their co-cultivation. The lowest ratio of auxin/cytokinin was found in B. japonicum M-8 and A. brasilense 410 culture fluid under their co-cultivation, which should positively influence the formation of a symbiotic system when interacting with soybean plants. Conclusion. A combination of cultivating rhizobia and azospirilla showed an increase in the amount of cytokinins and gibberellins in the culture fluid of the microorganisms, a decrease in the amount of abscisic acid and improvement in the auxin/cytokinin ratio compared to the values of the pure cultures of the nitrogen-fixing bacteria studied. An analysis of the quantitative parameters of the content of phytohormones suggests the feasibility of combining B. japonicum and A. brasilense in a mixed culture for the effective introduction of rhizobia in soybean agrocenosis.

scholarly journals MICROBIOCENOSIS OF RHIZOSPHERIC SOIL AND PRODUCTIVITY OF WINTER WHEAT UNDER THE USE OF AGROBACTERIUM RADIOBACTER 204, ACTIVATED WITH NANOCARBOXYLATES OF METALS

2017 ◽  
Vol 26 ◽  
pp. 17-23
Author(s):  
S. F. Kozar ◽  
T. A. Evtushenko ◽  
T. O. Usmanova ◽  
Ye. P. Symonenko
Keyword(s):  
Trace Elements ◽  
Winter Wheat ◽  
Rhizosphere Soil ◽  
Wheat Yield ◽  
Rhizospheric Soil ◽  
Nitrogen Fixing ◽  
Agrobacterium Radiobacter ◽  
Nitrogen Fixing Bacteria ◽  
Control Variant ◽  
Wheat Seeds

The effectiveness of pre-sowing inoculation of winter wheat seeds with Agrobacterium radiobacter204, pre-activated with nanocarboxylates of metals, and the preparation Avatar (a complex of traceelements - metal nanocarboxylates), applied in combination and separately, was studied. The combinedapplication of bacterization and a complex of trace elements positively affects the microbiocenosis of therhizospheric soil of winter wheat: an increase in the number of ammonifiers (from 43.8% to 77.1%),nitrogen-fixing bacteria (from 2.7 to 3.5 times) was noted, while the number of micromycetes reduced.Pre-sowing bacterization and application of nanocarboxylates of metals contributes to the increase of thepotential nitrogen-fixing activity of rhizosphere soil and increase of wheat yield by 24.4% compared withthe control variant.

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