| 1. |
- Anslan, Sten, et al.
(författare)
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Temporal changes in fungal communities associated with guts and appendages of Collembola as based on culturing and high-throughput sequencing
- 2016
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 96, s. 152-159
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Tidskriftsartikel (refereegranskat)abstract
- Due to high abundance and feeding habits, invertebrates are of great importance for shaping microbial communities at the fine scale. Springtails (Collembola) that feed on fungal spores and mycelia may contribute to dispersal through carrying fungal propagules in their guts or on their appendages. The Collembola–fungal associations are mainly investigated by microscopy or culturing techniques, which allow identify only fungi that have distinctive morphological characteristics or that can be cultured in vitro. Here we identified the Collembola-associated fungi on the body surface and in the gut content using both culturing and high-throughput sequencing (HTS) methods. We studied three epigeic Collembola species found on the Norway spruce dominated forest stands throughout the vegetation period – Entomobrya nivalis, Orchesella flavescens andPogonognathellus longicornis. We discovered over 1200 fungal operational taxonomic units (OTUs), i.e. the proxies for species, based on 97% sequence similarity of the ITS2 subregion of ribosomal DNA. Most of the fungi were saprotrophs, but we detected also mycorrhizal, parasitic and lichenized fungi. Season was the most important factor affecting fungal richness and composition, especially on body surface. Although the data matrix revealed significant effect of substrate, we were unable to detect the significant fungal community differences between body surface and gut samples of conspecifics. There were no significant differences among studied epigeic Collembola species in the preference for fungal diet. Our study demonstrates that collembolans associate with a broader range of fungi than previously observed and thus potentially play an important role in enhancing fungal colonization through dispersal activities.
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| 2. |
- Bahram, Mohammad, et al.
(författare)
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Stochastic distribution of small soil eukaryotes resulting from high dispersal and drift in a local environment
- 2016
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Ingår i: The ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 10, s. 885-896
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Tidskriftsartikel (refereegranskat)abstract
- A central challenge in ecology is to understand the relative importance of processes that shape diversity patterns. Compared with aboveground biota, little is known about spatial patterns and processes in soil organisms. Here we examine the spatial structure of communities of small soil eukaryotes to elucidate the underlying stochastic and deterministic processes in the absence of environmental gradients at a local scale. Specifically, we focus on the fine-scale spatial autocorrelation of prominent taxonomic and functional groups of eukaryotic microbes. We collected 123 soil samples in a nested design at distances ranging from 0.01 to 64 m from three boreal forest sites and used 454 pyrosequencing analysis of Internal Transcribed Spacer for detecting Operational Taxonomic Units of major eukaryotic groups simultaneously. Among the main taxonomic groups, we found significant but weak spatial variability only in the communities of Fungi and Rhizaria. Within Fungi, ectomycorrhizas and pathogens exhibited stronger spatial structure compared with saprotrophs and corresponded to vegetation. For the groups with significant spatial structure, autocorrelation occurred at a very fine scale (<2 m). Both dispersal limitation and environmental selection had a weak effect on communities as reflected in negative or null deviation of communities, which was also supported by multivariate analysis, that is, environment, spatial processes and their shared effects explained on average <10% of variance. Taken together, these results indicate a random distribution of soil eukaryotes with respect to space and environment in the absence of environmental gradients at the local scale, reflecting the dominant role of drift and homogenizing dispersal.
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| 3. |
- Tedersoo, Leho, et al.
(författare)
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Genomics and metagenomics technologies to recover ribosomal DNA and single-copy genes from old fruit-body and ectomycorrhiza specimens
- 2016
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Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; :13, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- High-throughput sequencing (HTS) has become a standard technique for genomics, metagenomics and taxonomy, but these analyses typically require large amounts of high-quality DNA that is difficult to obtain from uncultivable organisms including fungi with no living culture or fruit-body representatives. By using 1 ng DNA and low coverage Illumina HiSeqHTS, we evaluated the usefulness of genomics and metagenomics tools to recover fungal barcoding genes from old and problematic specimens of fruit-bodies and ectomycorrhizal (EcM) root tips. Ribosomal DNA and single-copy genes were successfully recovered from both fruit-body and EcM specimens typically <10 years old (maximum, 17 years). Samples with maximum obtained DNA concentration <0.2 ng µl-1 were sequenced poorly. Fungal rDNA molecules assembled from complex mock community and soil revealed a large proportion of chimeras and artefactual consensus sequences of closely related taxa. Genomics and metagenomics tools enable recovery of fungal genomes from very low initial amounts of DNA from fruit-bodies and ectomycorrhizas, but these genomes include a large proportion of prokaryote and other eukaryote DNA. Nonetheless, the recovered scaffolds provide an important source for phylogenetic and phylogenomic analyses and mining of functional genes.
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