scholarly journals Bark decomposition in white oak soil outperforms eastern hemlock soil, while bark type leads to consistent changes in soil microbial composition

2020 ◽  
Vol 150 (3) ◽  
pp. 329-343
Author(s):  
Rondy J. Malik ◽  
Ryan V. Trexler ◽  
David M. Eissenstat ◽  
Terrence H. Bell
Keyword(s):  
Leaf Litter ◽  
Soil Type ◽  
High Throughput Sequencing ◽  
Eastern Hemlock ◽  
Rrna Gene ◽  
Quercus Alba ◽  
White Oak ◽  
Microbial Composition ◽  
Soil Microbial ◽  
Soil Microbial Composition

Abstract Bark decomposition is an underexamined component of soil carbon cycling and soil community assembly. Numerous studies have shown faster decomposition of leaf litter in “home” environments (i.e. within soil adjacent to the plant that produced the leaves), suggesting potential legacy effects from previous deposition of similar litter. This is expected to occur through, in part, accumulation of microorganisms that metabolize substrates the litter provides. Whether a similar “home-field advantage” (HFA) exists for bark decomposition is unknown, but this dynamic may differ because annual bark deposits to soil are minimal relative to leaf deposits. We hypothesized that (1) as with leaf litter, bark will be better decomposed near to the tree from which it was collected, and (2) that decomposing bark can initiate change in soil microbial composition. To test these hypotheses, we used a full factorial design that included two bark types (collected from eastern hemlock, Tsuga canadensis, and white oak, Quercus alba) and two soil types (‘home’ and ‘away’) within a temperate mixed hardwood forest at the Shale Hills Catchment in central Pennsylvania, USA. Bark was excised from 25 replicates of each tree type, buried in either home or away soil, and incubated belowground from July 2017 to June 2018. Decomposition was assessed through proportionate mass loss over time, while microbial composition in the bark and adjacent soil was assessed through high-throughput sequencing of 16S rRNA gene and fungal ITS fragments. Overall, bark degraded faster in white oak soils, and there was also an effect of bark type on decomposition. Although white oak bark decomposed more quickly in its home environment, this could be due to either soil conditioning or inherent differences in the soils in which each species grows. Soil microbial assemblages also sorted according to bark type rather than soil type, suggesting that bark strongly influences the composition of nearby microorganisms during decomposition. Our results suggest that both bark type and soil type are important factors during bark decomposition, but our findings suggest no clear evidence for HFA.

scholarly journals Effects of Glucosinolate-Derived Isothiocyanates on Fungi: A Comprehensive Review on Direct Effects, Mechanisms, Structure-Activity Relationship Data and Possible Agricultural Applications

2021 ◽  
Vol 7 (7) ◽  
pp. 539
Author(s):  
Tamás Plaszkó ◽  
Zsolt Szűcs ◽  
Gábor Vasas ◽  
Sándor Gonda
Keyword(s):  
Mycorrhizal Fungi ◽  
Current Knowledge ◽  
Synergistic Activity ◽  
Microbial Composition ◽  
Soil Microbial ◽  
Structure Activity ◽  
Agricultural Applications ◽  
Antifungal Action ◽  
Insight Into ◽  
Soil Microbial Composition

Plants heavily rely on chemical defense systems against a variety of stressors. The glucosinolates in the Brassicaceae and some allies are the core molecules of one of the most researched such pathways. These natural products are enzymatically converted into isothiocyanates (ITCs) and occasionally other defensive volatile organic constituents (VOCs) upon fungal challenge or tissue disruption to protect the host against the stressor. The current review provides a comprehensive insight on the effects of the isothiocyanates on fungi, including, but not limited to mycorrhizal fungi and pathogens of Brassicaceae. In the review, our current knowledge on the following topics are summarized: direct antifungal activity and the proposed mechanisms of antifungal action, QSAR (quantitative structure-activity relationships), synergistic activity of ITCs with other agents, effects of ITCs on soil microbial composition and allelopathic activity. A detailed insight into the possible applications is also provided: the literature of biofumigation studies, inhibition of post-harvest pathogenesis and protection of various products including grains and fruits is also reviewed herein.

scholarly journals Disentangling Responses of the Subsurface Microbiome to Wetland Status and Implications for Indicating Ecosystem Functions

2021 ◽  
Vol 9 (2) ◽  
pp. 211
Author(s):  
Jie Gao ◽  
Miao Liu ◽  
Sixue Shi ◽  
Ying Liu ◽  
Yu Duan ◽  
...  
Keyword(s):  
Microbial Community ◽  
High Throughput Sequencing ◽  
Carbon Fixation ◽  
Microbial Community Composition ◽  
Ecosystem Functions ◽  
Microbial Composition ◽  
Wetland Ecosystems ◽  
Soil Microbial ◽  
Geochemical Properties ◽  
Microbial Groups

In this study, we analyzed microbial community composition and the functional capacities of degraded sites and restored/natural sites in two typical wetlands of Northeast China—the Phragmites marsh and the Carex marsh, respectively. The degradation of these wetlands, caused by grazing or land drainage for irrigation, alters microbial community components and functional structures, in addition to changing the aboveground vegetation and soil geochemical properties. Bacterial and fungal diversity at the degraded sites were significantly lower than those at restored/natural sites, indicating that soil microbial groups were sensitive to disturbances in wetland ecosystems. Further, a combined analysis using high-throughput sequencing and GeoChip arrays showed that the abundance of carbon fixation and degradation, and ~95% genes involved in nitrogen cycling were increased in abundance at grazed Phragmites sites, likely due to the stimulating impact of urine and dung deposition. In contrast, the abundance of genes involved in methane cycling was significantly increased in restored wetlands. Particularly, we found that microbial composition and activity gradually shifts according to the hierarchical marsh sites. Altogether, this study demonstrated that microbial communities as a whole could respond to wetland changes and revealed the functional potential of microbes in regulating biogeochemical cycles.

scholarly journals Vineyard under-vine floor management alters soil microbial composition, while the fruit microbiome shows no corresponding shifts

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Ming-Yi Chou ◽  
Justine Vanden Heuvel ◽  
Terrence H. Bell ◽  
Kevin Panke-Buisse ◽  
Jenny Kao-Kniffin
Keyword(s):  
Microbial Composition ◽  
Soil Microbial ◽  
Soil Microbial Composition

scholarly journals Bioconductor workflow for microbiome data analysis: from raw reads to community analyses

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1492 ◽  
Author(s):  
Ben J. Callahan ◽  
Kris Sankaran ◽  
Julia A. Fukuyama ◽  
Paul J. McMurdie ◽  
Susan P. Holmes
Keyword(s):  
High Throughput Sequencing ◽  
Linear Models ◽  
Reference Database ◽  
Rrna Gene ◽  
Microbial Composition ◽  
Nonparametric Testing ◽  
Abundance Estimates ◽  
Taxonomic Markers ◽  
Microbiome Data ◽  
Microbiome Data Analysis

High-throughput sequencing of PCR-amplified taxonomic markers (like the 16S rRNA gene) has enabled a new level of analysis of complex bacterial communities known as microbiomes. Many tools exist to quantify and compare abundance levels or microbial composition of communities in different conditions. The sequencing reads have to be denoised and assigned to the closest taxa from a reference database. Common approaches use a notion of 97% similarity and normalize the data by subsampling to equalize library sizes. In this paper, we show that statistical models allow more accurate abundance estimates. By providing a complete workflow in R, we enable the user to do sophisticated downstream statistical analyses, including both parameteric and nonparametric methods. We provide examples of using the R packages dada2, phyloseq, DESeq2, ggplot2 and vegan to filter, visualize and test microbiome data. We also provide examples of supervised analyses using random forests, partial least squares and linear models as well as nonparametric testing using community networks and the ggnetwork package.

scholarly journals Microbial Composition of Human Appendices from Patients following Appendectomy

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Caitriona M. Guinane ◽  
Amany Tadrous ◽  
Fiona Fouhy ◽  
C. Anthony Ryan ◽  
Eugene M. Dempsey ◽  
...  
Keyword(s):  
Human Health ◽  
High Throughput ◽  
High Throughput Sequencing ◽  
Evolutionary Development ◽  
Rrna Gene ◽  
Limited Data ◽  
Microbial Composition ◽  
Content Type ◽  
Study Results ◽  
Human Appendix

ABSTRACT The human appendix has historically been considered a vestige of evolutionary development with an unknown function. While limited data are available on the microbial composition of the appendix, it has been postulated that this organ could serve as a microbial reservoir for repopulating the gastrointestinal tract in times of necessity. We aimed to explore the microbial composition of the human appendix, using high-throughput sequencing of the 16S rRNA gene V4 region. Seven patients, 5 to 25 years of age, presenting with symptoms of acute appendicitis were included in this study. Results showed considerable diversity and interindividual variability among the microbial composition of the appendix samples. In general, however, Firmicutes was the dominant phylum, with the majority of additional sequences being assigned at various levels to Proteobacteria, Bacteroidetes, Actinobacteria, and Fusobacteria. Despite the large diversity in the microbiota found within the appendix, however, a few major families and genera were found to comprise the majority of the sequences present. Interestingly, also, certain taxa not generally associated with the human intestine, including the oral pathogens Gemella, Parvimonas, and Fusobacterium, were identified among the appendix samples. The prevalence of genera such as Fusobacterium could also be linked to the severity of inflammation of the organ. We conclude that the human appendix contains a robust and varied microbiota distinct from the microbiotas in other niches within the human microbiome. The microbial composition of the human appendix is subject to extreme variability and comprises a diversity of biota that may play an important, as-yet-unknown role in human health. IMPORTANCE There are currently limited data available on the microbial composition of the human appendix. It has been suggested, however, that it may serve as a “safe house” for commensal bacteria that can reinoculate the gut at need. The present study is the first comprehensive view of the microbial composition of the appendix as determined by high-throughput sequencing. We have determined that the human appendix contains a wealth of microbes, including members of 15 phyla. Important information regarding the associated bacterial diversity of the appendix which will help determine the role, if any, the appendix microbiota has in human health is presented.

scholarly journals The Equine Faecal Microbiota Undergoes Step-wise Compositional Changes in Accordance With Increasing Levels of Domestication

2021 ◽  
Author(s):  
Katie Bull ◽  
Gareth Davies ◽  
Timothy Patrick Jenkins ◽  
Laura Elizabeth Peachey
Keyword(s):  
Adult Female ◽  
High Throughput Sequencing ◽  
Rrna Gene ◽  
Faecal Microbiota ◽  
Microbial Composition ◽  
Faecal Samples ◽  
High Incidence ◽  
Life Threatening ◽  
Group Variation ◽  
The Uk

Abstract BackgroundChanges to the gut microbiota are associated with an increased incidence of disease in many species. This is particularly important during the process of domestication, where captive animals commonly suffer from gastrointestinal (GI) pathology. Horses are a prime example of a species which suffers from a high incidence of (often life-threatening) GI diseases in domesticated environments. We aimed to indentify the gut microbial changes which occur due to domestication in horses by profiling the faecal microbiota of adult female Exmoor ponies under three management conditions, representing increasing levels of domestication.MethodsFaecal samples were collected from 29 adult female Exmoor ponies in the South West of the UK; ponies were categorised as Feral (n=10), Semi-Feral (n=10) and Domesticated (n=9), based on their management conditions; thus controlling for age, gender and random effects between groups. Diet and medication were recorded and faecal samples taken to assess parasite infection. Faecal microbial composition was profiled via high-throughput sequencing of the bacterial 16S rRNA gene.ResultsDownstream biostatistical analysis indicated profound step-wise changes in global microbial community structure in the transition from Feral to Semi-Feral to Domesticated groups. A relatively high abundance of members of the phylum Proteobacteria and Tenericutes were associated with the Domesticated group; and higher levels of Methanobacteria were seen in the Feral group. The Semi-Feral group frequently had intermediate levels of these taxa; however, they also exhibited the greatest ‘within group’ variation in bacterial diversity and parasites burdens. Functional predictions revealed increased amino acid and lipid metabolism in the Domesticated group and increased energy metabolism in the Feral group; supporting a hypothesis that differences in diet was the key driver of gut microbial composition. ConclusionsIf assumed the Feral population has a more natural gut microbial phenotype, akin to that with which horses have evolved, these data can potentially be used to provide microbial signitures of balanced gut homeostasis in horses; which, in turn, will aid prevention of GI disease in domesticated horses.

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