The ecological effects of land-applying municipal biosolids on nitrogen-fixing bacteria

10.32920/ryerson.14655147.v1 ◽

2021 ◽

Author(s):

Leigh Maxine Holt

Keyword(s):

Nitrogen Fixation ◽

Community Structure ◽

Agricultural Soils ◽

Nitrogen Fixing ◽

Carbon Utilization ◽

Nitrogen Fixing Bacteria ◽

Amended Soils ◽

Biolog Ecoplates ◽

Utilization Patterns ◽

Municipal Biosolids

The effects of municipal biosolids on nitrogen-fixing bacteria were assessed in a three month soil incubation study. Treatments included reference agricultural soils, soil amended with municipal biosolids or manure, and biosolids without soil. Nitrogen-fixation rates in reference and manure-amended soil were similar, and lower than in biosolids treatments; respiration rates showed similar trends. At test termination there was no difference between soil treatments for nitrogen-fixation, but some enhanced respiration in the biosolids-amended soils. Community structure was assessed using Biolog EcoPlates™ and denaturing gradient gel electrphoresis with a nitrogen-fixing gene (nifH). EcoPlate™ carbon utilization patterns corresponded with activity measures, with no difference among soil treatments at test termination. Nitrogen-fixing gene patterns showed a potential shift in community structure of biosolids-amended soils three months post-amendment. In general, the effects on the activity and structure of nitrogen-fixing communities were largely temporary; however, this study evaluated a one-time biosolids application. The potential for cumulative effects requires further investigation.

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Seasonal changes in rates of nitrogen-fixation (AR) and numbers of potential nitrogen-fixing bacteria associated with excised roots of aquatic angiosperms

Aquatic Botany ◽

10.1016/0304-3770(82)90021-3 ◽

1982 ◽

Vol 12 ◽

pp. 257-276 ◽

Cited By ~ 6

Author(s):

M.T. Ogan

Keyword(s):

Nitrogen Fixation ◽

Seasonal Changes ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Aquatic Angiosperms

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

Scientific Reports ◽

10.1038/s41598-021-88380-8 ◽

2021 ◽

Vol 11 (1) ◽

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 ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Promising Tool ◽

A Genome ◽

Plant Growth Promoting ◽

Growth Promoting

AbstractPrevious studies have shown the sugarcane microbiome harbors diverse plant growth promoting microorganisms, including nitrogen-fixing bacteria (diazotrophs), which can serve as biofertilizers. The genomes of 22 diazotrophs from Colombian sugarcane fields were sequenced to investigate potential biofertilizers. A genome-enabled computational phenotyping approach was developed to prioritize sugarcane associated diazotrophs according to their potential as biofertilizers. This method selects isolates that have potential for nitrogen fixation and other plant growth promoting (PGP) phenotypes while showing low risk for virulence and antibiotic resistance. Intact nitrogenase (nif) genes and operons were found in 18 of the isolates. Isolates also encode phosphate solubilization and siderophore production operons, and other PGP genes. The majority of sugarcane isolates showed uniformly low predicted virulence and antibiotic resistance compared to clinical isolates. Six strains with the highest overall genotype scores were experimentally evaluated for nitrogen fixation, phosphate solubilization, and the production of siderophores, gibberellic acid, and indole acetic acid. Results from the biochemical assays were consistent and validated computational phenotype predictions. A genotypic and phenotypic threshold was observed that separated strains by their potential for PGP versus predicted pathogenicity. Our results indicate that computational phenotyping is a promising tool for the assessment of bacteria detected in agricultural ecosystems.

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Phospholipid fatty acid profiles and carbon utilization patterns for analysis of microbial community structure under field and greenhouse conditions

FEMS Microbiology Ecology ◽

10.1111/j.1574-6941.1998.tb00501.x ◽

1998 ◽

Vol 26 (2) ◽

pp. 151-163 ◽

Cited By ~ 104

Author(s):

Abasiofiok M Ibekwe ◽

Ann.C Kennedy

Keyword(s):

Community Structure ◽

Fatty Acid ◽

Microbial Community ◽

Microbial Community Structure ◽

Phospholipid Fatty Acid ◽

Fatty Acid Profiles ◽

Carbon Utilization ◽

Utilization Patterns

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Endophytic nitrogen fixation – a possible ‘hidden’ source of nitrogen for lodgepole pine trees growing at unreclaimed gravel mining sites

FEMS Microbiology Ecology ◽

10.1093/femsec/fiz172 ◽

2019 ◽

Vol 95 (11) ◽

Cited By ~ 8

Author(s):

Kiran Preet Padda ◽

Akshit Puri ◽

Chris Chanway

Keyword(s):

Nitrogen Fixation ◽

Lodgepole Pine ◽

Nifh Gene ◽

Control Treatment ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Mining Sites ◽

Greenhouse Study ◽

Gravel Mining ◽

Pine Trees

ABSTRACT Lodgepole pine (Pinus contorta var. latifolia) trees have been thriving on unreclaimed gravel mining sites in British Columbia, Canada, with tissue nitrogen-content and growth-rate unaffected by extremely low soil nitrogen-levels. This indicates that pine trees could be accessing a hidden nitrogen source to fulfill their nitrogen requirements – possibly via endophytic nitrogen-fixation. Endophytic bacteria originally isolated from native pine trees growing at gravel sites were selected (n = 14) for in vitro nitrogen-fixation assays and a year long greenhouse study to test the overall hypothesis that naturally occurring endophytic nitrogen-fixing bacteria sustain pine tree growth under nitrogen-limited conditions. Each of the 14 bacteria colonized the internal tissues of pine trees in the greenhouse study and fixed significant amounts of nitrogen from atmosphere (23%–53%) after one year as estimated through 15N isotope dilution assay. Bacterial inoculation also significantly enhanced the length (31%–64%) and biomass (100%–311%) of pine seedlings as compared to the non-inoculated control treatment. In addition, presence of the nifH gene was confirmed in all 14 bacteria. Our results support the possibility that pine trees associate with nitrogen-fixing bacteria, capable of endophytic colonization, to survive at unreclaimed gravel mining pits and this association could potentially be utilized for effective reclamation of highly disturbed sites in a sustainable manner.

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Differing Courses of Genetic Evolution of Bradyrhizobium Inoculants as Revealed by Long-Term Molecular Tracing in Acacia mangium Plantations

Applied and Environmental Microbiology ◽

10.1128/aem.02007-14 ◽

2014 ◽

Vol 80 (18) ◽

pp. 5709-5716 ◽

Cited By ~ 2

Author(s):

M. M. Perrineau ◽

C. Le Roux ◽

A. Galiana ◽

A. Faye ◽

R. Duponnois ◽

...

Keyword(s):

Nitrogen Fixation ◽

Growth Promotion ◽

Acacia Mangium ◽

Housekeeping Genes ◽

Nitrogen Fixing ◽

Microbial Inoculants ◽

Nitrogen Fixing Bacteria ◽

Content Type ◽

Significant Difference

ABSTRACTIntroducing nitrogen-fixing bacteria as an inoculum in association with legume crops is a common practice in agriculture. However, the question of the evolution of these introduced microorganisms remains crucial, both in terms of microbial ecology and agronomy. We explored this question by analyzing the genetic and symbiotic evolution of twoBradyrhizobiumstrains inoculated onAcacia mangiumin Malaysia and Senegal 15 and 5 years, respectively, after their introduction. Based on typing of several loci, we showed that these two strains, although closely related and originally sampled in Australia, evolved differently. One strain was recovered in soil with the same five loci as the original isolate, whereas the symbiotic cluster of the other strain was detected with no trace of the three housekeeping genes of the original inoculum. Moreover, the nitrogen fixation efficiency was variable among these isolates (either recombinant or not), with significantly high, low, or similar efficiencies compared to the two original strains and no significant difference between recombinant and nonrecombinant isolates. These data suggested that 15 years after their introduction, nitrogen-fixing bacteria remain in the soil but that closely related inoculant strains may not evolve in the same way, either genetically or symbiotically. In a context of increasing agronomical use of microbial inoculants (for biological control, nitrogen fixation, or plant growth promotion), this result feeds the debate on the consequences associated with such practices.

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Asymbiotic N2-fixing bacteria associated with three boreal conifers

Canadian Journal of Forest Research ◽

10.1139/x84-107 ◽

1984 ◽

Vol 14 (4) ◽

pp. 595-597 ◽

Cited By ~ 4

Author(s):

L. Z. Florence ◽

F. D. Cook

Keyword(s):

Nitrogen Fixation ◽

Acetylene Reduction ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Seedling Root ◽

Natural Stands

Azotobacter spp., Azospirillum spp., and Desulfovibrio spp., were identified as the predominant nitrogen-fixing bacteria associated with seedling root sections collected from natural stands of Pinusbanksiana Lamb., Piceamariana (Mill.) B.S.P., and Larixlaricina (Du Roi) K. Koch growing in Alberta. Samples from the sandy upland habitat of P. banksiana exhibited lower average rates of nitrogen fixation relative to the wet lowland occupied by P. mariana and L. laricina. Average nitrogen-fixing capacity (by acetylene reduction) was greater among bacteria isolates from L. laricina than those from P. mariana. Azospirillum spp. were strongly associated with P. mariana, while Azotobacter spp. were isolated more frequently from L. laricina.

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Nitrogen Fixation in Pozol, a Traditional Fermented Beverage

Applied and Environmental Microbiology ◽

10.1128/aem.00588-20 ◽

2020 ◽

Vol 86 (16) ◽

Author(s):

Jocelin Rizo ◽

Marco A. Rogel ◽

Daniel Guillén ◽

Carmen Wacher ◽

Esperanza Martinez-Romero ◽

...

Keyword(s):

Nitrogen Fixation ◽

Acetylene Reduction ◽

Growth Promotion ◽

Point Of View ◽

Intestinal Microbiome ◽

Acetylene Reduction Activity ◽

Nitrogen Fixing ◽

Nitrogen Fixing Bacteria ◽

Free Living ◽

Functional Perspective

ABSTRACT Traditional fermentations have been widely studied from the microbiological point of view, but little is known from the functional perspective. In this work, nitrogen fixation by free-living nitrogen-fixing bacteria was conclusively demonstrated in pozol, a traditional Mayan beverage prepared with nixtamalized and fermented maize dough. Three aspects of nitrogen fixation were investigated to ensure that fixation actually happens in the dough: (i) the detection of acetylene reduction activity directly in the substrate, (ii) the presence of potential diazotrophs, and (iii) an in situ increase in acetylene reduction by inoculation with one of the microorganisms isolated from the dough. Three genera were identified by sequencing the 16S rRNA and nifH genes as Kosakonia, Klebsiella, and Enterobacter, and their ability to fix nitrogen was confirmed. IMPORTANCE Nitrogen-fixing bacteria are found in different niches, as symbionts in plants, in the intestinal microbiome of several insects, and as free-living microorganisms. Their use in agriculture for plant growth promotion via biological nitrogen fixation has been extensively reported. This work demonstrates the ecological and functional importance that these bacteria can have in food fermentations, reevaluating the presence of these genera as an element that enriches the nutritional value of the dough.

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