scholarly journals 16S rRNA metagenomic analysis of the bacterial community associated with turf grass seeds from low moisture and high moisture climates

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8417 ◽  
Author(s):  
Qiang Chen ◽  
William A. Meyer ◽  
Qiuwei Zhang ◽  
James F. White
Keyword(s):  
Microbial Community ◽  
Seed Germination ◽  
Bacterial Community ◽  
16S Rrna ◽  
Seedling Growth ◽  
Bacterial Communities ◽  
Metagenomic Analysis ◽  
High Moisture ◽  
Core Microbiome ◽  
Dry Climates

Turfgrass investigators have observed that plantings of grass seeds produced in moist climates produce seedling stands that show greater stand evenness with reduced disease compared to those grown from seeds produced in dry climates. Grass seeds carry microbes on their surfaces that become endophytic in seedlings and promote seedling growth. We hypothesize that incomplete development of the microbiome associated with the surface of seeds produced in dry climates reduces the performance of seeds. Little is known about the influence of moisture on the structure of this microbial community. We conducted metagenomic analysis of the bacterial communities associated with seeds of three turf species (Festuca rubra, Lolium arundinacea, and Lolium perenne) from low moisture (LM) and high moisture (HM) climates. The bacterial communities were characterized by Illumina high-throughput sequencing of 16S rRNA V3–V4 regions. We performed seed germination tests and analyzed the correlations between the abundance of different bacterial groups and seed germination at different taxonomy ranks. Climate appeared to structure the bacterial communities associated with seeds. LM seeds vectored mainly Proteobacteria (89%). HM seeds vectored a denser and more diverse bacterial community that included Proteobacteria (50%) and Bacteroides (39%). At the genus level, Pedobacter (20%), Sphingomonas (13%), Massilia (12%), Pantoea (12%) and Pseudomonas (11%) were the major genera in the bacterial communities regardless of climate conditions. Massilia, Pantoea and Pseudomonas dominated LM seeds, while Pedobacter and Sphingomonas dominated HM seeds. The species of turf seeds did not appear to influence bacterial community composition. The seeds of the three turf species showed a core microbiome consisting of 27 genera from phyla Actinobacteria, Bacteroidetes, Patescibacteria and Proteobacteria. Differences in seed-vectored microbes, in terms of diversity and density between high and LM climates, may result from effects of moisture level on the colonization of microbes and the development of microbe community on seed surface tissues (adherent paleas and lemmas). The greater diversity and density of seed vectored microbes in HM climates may benefit seedlings by helping them tolerate stress and fight disease organisms, but this dense microbial community may also compete with seedlings for nutrients, slowing or modulating seed germination and seedling growth.

scholarly journals Diversity and Structure of the Endophytic Bacterial Communities Associated With Three Terrestrial Orchid Species as Revealed by 16S rRNA Gene Metabarcoding

2020 ◽  
Vol 11 ◽  
Author(s):  
Pasquale Alibrandi ◽  
Sylvia Schnell ◽  
Silvia Perotto ◽  
Massimiliano Cardinale
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Host Plant ◽  
Bacterial Communities ◽  
Reproductive Organs ◽  
Distribution Model ◽  
Rrna Gene ◽  
Orchid Species ◽  
Core Microbiota

The endophytic microbiota can establish mutualistic or commensalistic interactions within the host plant tissues. We investigated the bacterial endophytic microbiota in three species of Mediterranean orchids (Neottia ovata, Serapias vomeracea, and Spiranthes spiralis) by metabarcoding of the 16S rRNA gene. We examined whether the different orchid species and organs, both underground and aboveground, influenced the endophytic bacterial communities. A total of 1,930 operational taxonomic units (OTUs) were obtained, mainly Proteobacteria and Actinobacteria, whose distribution model indicated that the plant organ was the main determinant of the bacterial community structure. The co-occurrence network was not modular, suggesting a relative homogeneity of the microbiota between both plant species and organs. Moreover, the decrease in species richness and diversity in the aerial vegetative organs may indicate a filtering effect by the host plant. We identified four hub OTUs, three of them already reported as plant-associated taxa (Pseudoxanthomonas, Rhizobium, and Mitsuaria), whereas Thermus was an unusual member of the plant microbiota. Core microbiota analysis revealed a selective and systemic ascent of bacterial communities from the vegetative to the reproductive organs. The core microbiota was also maintained in the S. spiralis seeds, suggesting a potential vertical transfer of the microbiota. Surprisingly, some S. spiralis seed samples displayed a very rich endophytic microbiota, with a large number of OTUs shared with the roots, a situation that may lead to a putative restoring process of the root-associated microbiota in the progeny. Our results indicate that the bacterial community has adapted to colonize the orchid organs selectively and systemically, suggesting an active involvement in the orchid holobiont.

scholarly journals Ecological Succession of Bacterial Communities during Conventionalization of Germ-Free Mice

2012 ◽  
Vol 78 (7) ◽  
pp. 2359-2366 ◽  
Author(s):  
Merritt G. Gillilland ◽  
John R. Erb-Downward ◽  
Christine M. Bassis ◽  
Michael C. Shen ◽  
Galen B. Toews ◽  
...  
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
Bacterial Communities ◽  
Structural Heterogeneity ◽  
Ecological Succession ◽  
Rrna Gene ◽  
Gi Tract ◽  
Content Type ◽  
Germ Free ◽  
Over Time

ABSTRACTLittle is known about the dynamics of early ecological succession during experimental conventionalization of the gastrointestinal (GI) tract; thus, we measured changes in bacterial communities over time, at two different mucosal sites (cecum and jejunum), with germfree C57BL/6 mice as the recipients of cecal contents (input community) from a C57BL/6 donor mouse. Bacterial communities were monitored using pyrosequencing of 16S rRNA gene amplicon libraries from the cecum and jejunum and analyzed by a variety of ecological metrics. Bacterial communities, at day 1 postconventionalization, in the cecum and jejunum had lower diversity and were distinct from the input community (dominated by eitherEscherichiaorBacteroides). However, by days 7 and 21, the recipient communities had become significantly diverse and the cecal communities resembled those of the donor and donor littermates, confirming that transfer of cecal contents results in reassembly of the community in the cecum 7 to 21 days later. However, bacterial communities in the recipient jejunum displayed significant structural heterogeneity compared to each other or the donor inoculum or the donor littermates, suggesting that the bacterial community of the jejunum is more dynamic during the first 21 days of conventionalization. This report demonstrates that (i) mature input communities do not simply reassemble at mucosal sites during conventionalization (they first transform into a “pioneering” community and over time take on the appearance, in membership and structure, of the original input community) and (ii) the specific mucosal environment plays a role in shaping the community.

scholarly journals Effect of Wastewater Treatment Plant Effluent on Microbial Function and Community Structure in the Sediment of a Freshwater Stream with Variable Seasonal Flow

2008 ◽  
Vol 74 (9) ◽  
pp. 2659-2668 ◽  
Author(s):  
Steven A. Wakelin ◽  
Matt J. Colloff ◽  
Rai S. Kookana
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
16S Rrna ◽  
Wastewater Treatment Plant ◽  
Bacterial Communities ◽  
Nutrient Loading ◽  
Treatment Plant ◽  
Biogeochemical Cycling ◽  
Rrna Genes

ABSTRACT We investigated the effects of wastewater treatment plant (WWTP) discharge on the ecology of bacterial communities in the sediment of a small, low-gradient stream in South Australia. The quantification of genes involved in the biogeochemical cycling of carbon and nitrogen was used to assess potential impacts on ecosystem functions. The effects of disturbance on bacterial community structure were assessed by PCR-denaturing gradient gel electrophoresis of 16S rRNA genes, and clone library analysis was used to phylogenetically characterize significant shifts. Significant (P < 0.05) shifts in bacterial community structures were associated with alteration of the sediment's physicochemical properties, particularly nutrient loading from the WWTP discharge. The effects were greatest at the sampling location 400 m downstream of the outfall where the stream flow is reduced. This highly affected stretch of sediment contained representatives of the gammaproteobacteria that were absent from less-disturbed sites, including Oceanospirillales and Methylococcaceae. 16S rRNA gene sequences from less-disturbed sites had representatives of the Caulobacteraceae, Sphingomonadaceae, and Nitrospirae which were not represented in samples from disturbed sediment. The diversity was lowest at the reference site; it increased with proximity to the WWTP outfall and declined toward highly disturbed (400 m downstream) sites (P < 0.05). The potential for biological transformations of N varied significantly with the stream sediment location (P < 0.05). The abundance of amoA, narG, and nifH genes increased with the distance downstream of the outfall. These processes are driven by N and C availability, as well as redox conditions. Together these data suggest cause and effect between nutrient loading into the creek, shift in bacterial communities through habitat change, and alteration of capacity for biogeochemical cycling of N.

scholarly journals The Gut Microbial Community of Antarctic Fish Detected by 16S rRNA Gene Sequence Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Song ◽  
Lingzhi Li ◽  
Hongliang Huang ◽  
Keji Jiang ◽  
Fengying Zhang ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Bacterial Communities ◽  
Antarctic Fish ◽  
16S Rrna Gene Sequencing ◽  
Physiological Characteristics ◽  
Rrna Gene ◽  
Rrna Gene Sequencing ◽  
Gut Microbial Community

Intestinal bacterial communities are highly relevant to the digestion, nutrition, growth, reproduction, and a range of fitness in fish, but little is known about the gut microbial community in Antarctic fish. In this study, the composition of intestinal microbial community in four species of Antarctic fish was detected based on 16S rRNA gene sequencing. As a result, 1 004 639 sequences were obtained from 13 samples identified into 36 phyla and 804 genera, in which Proteobacteria, Actinobacteria, Firmicutes, Thermi, and Bacteroidetes were the dominant phyla, and Rhodococcus, Thermus, Acinetobacter, Propionibacterium, Streptococcus, and Mycoplasma were the dominant genera. The number of common OTUs (operational taxonomic units) varied from 346 to 768, while unique OTUs varied from 84 to 694 in the four species of Antarctic fish. Moreover, intestinal bacterial communities in individuals of each species were not really similar, and those in the four species were not absolutely different, suggesting that bacterial communities might influence the physiological characteristics of Antarctic fish, and the common bacterial communities might contribute to the fish survival ability in extreme Antarctic environment, while the different ones were related to the living habits. All of these results could offer certain information for the future study of Antarctic fish physiological characteristics.

scholarly journals Composition and stability of bacterial communities associated with granular activated carbon and anthracite filters in a pilot scale municipal drinking water treatment facility

2012 ◽  
Vol 10 (2) ◽  
pp. 244-255 ◽  
Author(s):  
T. B. Shirey ◽  
R. W. Thacker ◽  
J. B. Olson
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Community Structure ◽  
Water Treatment ◽  
Bacterial Community ◽  
16S Rrna ◽  
Community Composition ◽  
Bacterial Communities ◽  
Granular Activated Carbon ◽  
Rrna Genes

Granular activated carbon (GAC) is an alternative filter substrate for municipal water treatment as it provides a high surface area suitable for microbial colonization. The resulting microbial growth promotes biodegradation of organic materials and other contaminants from influent waters. Here, the community structure of the bacteria associated with three GAC and two anthracite filters was examined over 12 months to monitor changes in community composition. Nearly complete 16S rRNA genes were polymerase chain reaction amplified for terminal restriction fragment length polymorphism (T-RFLP) analyses. The identity of commonly occurring peaks was determined through the construction of five representative 16S rRNA clone libraries. Based on sequence analysis, the bacterial communities associated with both anthracite and GAC filters appear to be composed of environmentally derived bacteria, with no known human pathogens. Analysis of similarity tests revealed that significant differences in bacterial community structure occurred over time, with filter substrate playing an important role in determining community composition. GAC filters exhibited the greatest degree of bacterial community variability over the sampling period, while anthracite filters showed a lower degree of variability and less change in community composition. Thus, GAC may be a suitable biologically active filter substrate for the treatment of municipal drinking water.

scholarly journals Methanogenic Granules Are Replicated, Whole Microbial Communities With Reproducible Responses To Environmental Cues

2020 ◽  
Author(s):  
Anna Christine Trego ◽  
Sarah O'Sullivan ◽  
Simon Mills ◽  
Estefania Porca ◽  
Christopher Quince ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
Size Fraction ◽  
Methanogenic Archaea ◽  
Organic Content ◽  
Environmental Cues ◽  
Rrna Gene ◽  
Core Microbiome ◽  
Methanogenic Activity ◽  
Fermentative Bacteria

Abstract Background In this study, individual anaerobic granular biofilms were used as true community replicates to assess whole-microbial-community responses to environmental cues. The aggregates originated from three different biomass sources, i.e. three different engineered biological wastewater treatment systems, were each size-separated into three fractions – small, medium and large – and characterised according to organic matter concentrations and rates of methanogenic activity. Differences in the microbial community structure of each size fraction from each source were determined using 16S rRNA gene sequencing. Subsequently, single granules from the large size fraction of one of the sources were separately subjected controlled environmental cues in novel micro batch reactors (mBRs). Results Organic content, methanogenic activity, and microbial community were significantly different between the three size fractions, with diversity trajectories replicated across the three sludge sources – indicating a potential development model as granules age. Individual large granules from one of these sources were statistically identical with respect to the structure of the active community based on cDNA analysis. It was observed that the active microbial community of individual granules, at the depth of 16S rRNA sequencing, produced reproducible responses to environmental conditions. While each condition resulted in the up-regulation of particular OTUs and clades, the core microbiome, consisting of many fermentative bacteria along with methanogenic archaea, namely, Methanosarcina and Methanobacterium , persisted. Conclusions At this level, single anaerobic granules can be considered highly-replicated whole-ecosystems, opening the door to high-throughput studies in Microbial Ecology.

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