scholarly journals Mechanisms of soil bacterial and fungal community assembly differ among and within islands

2020 ◽  
Vol 22 (4) ◽  
pp. 1559-1571 ◽  
Author(s):  
Pandeng Wang ◽  
Shao‐Peng Li ◽  
Xian Yang ◽  
Jizhong Zhou ◽  
Wensheng Shu ◽  
...  
Keyword(s):  
Fungal Community ◽  
Community Assembly ◽  
Soil Bacterial

Experimentally altered rainfall regimes and host root traits affect grassland arbuscular mycorrhizal fungal communities

2019 ◽  
Author(s):  
Coline Deveautour ◽  
Suzanne Donn ◽  
Sally Power ◽  
Kirk Barnett ◽  
Jeff Powell
Keyword(s):  
Fungal Community ◽  
Community Assembly ◽  
Root Length ◽  
Specific Root Length ◽  
Root Traits ◽  
Arbuscular Mycorrhizal ◽  
Fungal Communities ◽  
Rainfall Regime ◽  
Precipitation Regimes ◽  
Rainfall Regimes

Future climate scenarios predict changes in rainfall regimes. These changes are expected to affect plants via effects on the expression of root traits associated with water and nutrient uptake. Associated microorganisms may also respond to these new precipitation regimes, either directly in response to changes in the soil environment or indirectly in response to altered root trait expression. We characterised arbuscular mycorrhizal (AM) fungal communities in an Australian grassland exposed to experimentally altered rainfall regimes. We used Illumina sequencing to assess the responses of AM fungal communities associated with four plant species sampled in different watering treatments and evaluated the extent to which shifts were associated with changes in root traits. We observed that altered rainfall regimes affected the composition but not the richness of the AM fungal communities, and we found distinctive communities in the increased rainfall treatment. We found no evidence of altered rainfall regime effects via changes in host physiology because none of the studied traits were affected by changes in rainfall. However, specific root length was observed to correlate with AM fungal richness, while concentrations of phosphorus and calcium in root tissue and the proportion of root length allocated to fine roots were correlated to community composition. Our study provides evidence that climate change and its effects on rainfall may influence AM fungal community assembly, as do plant traits related to plant nutrition and water uptake. We did not find evidence that host responses to altered rainfall drive AM fungal community assembly in this grassland ecosystem.

scholarly journals Global diversity and biogeography of the Zostera marina mycobiome

2021 ◽  
Author(s):  
Cassandra L. Ettinger ◽  
Laura E. Vann ◽  
Jonathan A. Eisen
Keyword(s):  
Fungal Community ◽  
Community Assembly ◽  
Zostera Marina ◽  
High Throughput Sequencing ◽  
Marine Fungi ◽  
Marine Ecosystem ◽  
Fungal Community Composition ◽  
Functional Roles ◽  
Functional Guilds ◽  
The Many

Seagrasses are marine flowering plants that provide critical ecosystem services in coastal environments worldwide. Marine fungi are often overlooked in microbiome and seagrass studies, despite terrestrial fungi having critical functional roles as decomposers, pathogens or endophytes in global ecosystems. Here we characterize the distribution of fungi associated with the seagrass, Zostera marina, using leaves, roots, and rhizosphere sediment from 16 locations across its full biogeographic range. Using high throughput sequencing of the ribosomal internal transcribed spacer (ITS) region and 18S ribosomal RNA gene, we first measured fungal community composition and diversity. We then tested hypotheses of neutral community assembly theory and the degree to which deviations suggested amplicon sequence variants (ASVs) were plant-selected or dispersal-limited. Finally, we identified a core mycobiome and investigated the global distribution of differentially abundant ASVs. We found that the fungal community is significantly different between sites and that the leaf mycobiome follows a weak, but significant pattern of distance decay in the Pacific Ocean. Generally, there was evidence for both deterministic and stochastic factors contributing to community assembly of the mycobiome, with most taxa assembling through stochastic processes. The Z. marina core leaf and root mycobiomes were dominated by unclassified Sordariomycetes spp., unclassified Chytridiomycota lineages (including Lobulomycetaceae spp.), unclassified Capnodiales spp. and Saccharomyces sp. It is clear from the many unclassified fungal ASVs and fungal functional guilds, that knowledge of marine fungi is still rudimentary. Further studies characterizing seagrass-associated fungi are needed to understand the roles of these microorganisms generally and when associated with seagrasses. Importance Fungi have important functional roles when associated with land plants, yet very little is known about the roles of fungi associated with marine plants, like seagrasses. In this study, we report the results of a global effort to characterize the fungi associated with the seagrass, Zostera marina, across its full biogeographic range. Although we defined a putative global core fungal community, it is apparent from the many fungal sequences and predicted functional guilds that had no matches to existing databases, that general knowledge of seagrass-associated fungi and marine fungi generally is lacking. This work serves as an important foundational step towards future work investigating the functional ramifications of fungi in the marine ecosystem.

scholarly journals Deterministic Selection Dominates Microbial Community Assembly in Termite Mounds Across a Large Spatial Area

2020 ◽  
Author(s):  
Qing-Lin Chen ◽  
Hang-Wei Hu ◽  
Zhen-Zhen Yan ◽  
Chao-Yu Li ◽  
Bao-Anh Thi Nguyen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Stochastic Processes ◽  
Microbial Communities ◽  
Fungal Community ◽  
Community Assembly ◽  
Distance Decay ◽  
Termite Mounds ◽  
Deterministic Processes ◽  
Microbial Community Assembly

Abstract Background: Termites are ubiquitous insects in tropical and subtropical habitats, where they construct massive mounds from soil, their saliva and excreta. Termite mounds harbor an enormous amount of microbial inhabitants, which regulate multiple ecosystem functions such as mitigating methane emissions and increasing ecosystem resistance to climate change. However, we lack a mechanistic understanding about the role of termite mounds in modulating the microbial community assembly processes, which are essential to unravel the biological interactions of soil fauna and microorganisms, the major components of soil food webs. We conducted a large-scale survey across a >1500 km transect in northern Australia to investigate biogeographical patterns of bacterial and fungal community in 134 termite mounds and the relative importance of deterministic versus stochastic processes in microbial community assembly. Results: Microbial alpha (number of phylotypes) and beta (changes in bacterial and fungal community composition) significantly differed between termite mounds and surrounding soils. Microbial communities in termite mounds exhibited a significant distance-decay pattern, and fungal communities had a stronger distance-decay relationship (slope = -1.91) than bacteria (slope = -0.21). Based on the neutral community model (fitness < 0.7) and normalized stochasticity ratio index (NST) with a value below the 50% boundary point, deterministic selection, rather than stochastic forces, predominated the microbial community assembly in termite mounds. Deterministic processes exhibited significantly weaker impacts on bacteria (NST = 45.23%) than on fungi (NST = 33.72%), probably due to the wider habitat niche breadth and higher potential migration rate of bacteria. The abundance of antibiotic resistance genes (ARGs) was negatively correlated with bacterial/fungal biomass ratios, indicating that ARG content might be an important biotic factor that drove the biogeographic pattern of microbial communities in termite mounds. Conclusions: Deterministic processes play a more important role than stochastic processes in shaping the microbial community assembly in termite mounds, an unique habitat ubiquitously distributed in tropical and subtropical ecosystems. An improved understanding of the biogeographic patterns of microorganisms in termite mounds is crucial to decipher the role of soil faunal activities in shaping microbial community assembly, with implications for their mediated ecosystems functions and services.

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