Differences In Fungal Community Composition Research Articles

Spruce and beech as local determinants of forest fungal community structure in litter, humus and mineral soil

Beech forests reaches its native distribution limit in SE Norway, but is expected to expand substantially northwards due to climate warming. This may potentially result in a fundamental transformation of contemporary Northern European forests, with tentative effects on the associated belowground fungi. Fungal communities mediate vital ecosystem processes such as ecosystem productivity and carbon sequestration in boreal forests. To investigate how soil fungi is affected by the vegetation transition from spruce to beech forest, we sampled litter, humus and mineral soil in a forest landscape dominated by beech, spruce or a mixture of these. The fungal communities in the soil samples were analyzed by DNA metabarcoding of the rDNA ITS2 region. Although soil layers were the most important structuring gradient, we found clear differences in fungal species composition between spruce and beech plots. The differences in fungal community composition were most evident in the litter and least in the mineral soil. Decomposers, most notably Mycena, dominated the litter layer while various mycorrhizal fungi dominated the humus and mineral layers. Some ectomycorrhizal taxa, such as Cenoccocum and Russula, were more abundant in spruce forests. Differences in fungal community composition between forest types can potentially have large impacts on carbon sequestration rates.

Seagrass‐associated fungal communities follow Wallace's line, but host genotype does not structure fungal community

AbstractAimTo test whether or not fungal communities associated with the widespread seagrass, Syringodium isoetifolium can be differentiated on either side of Wallace's line, a boundary line separating Asian and Australasian fauna. Additionally, we examine whether host multilocus genotype predicts fungal community composition.LocationA total of 77 samples were collected from 14 sampling sites spanning the Indonesian archipelago.MethodsWe sequenced the fungal ITS1 gene using Illumia MiSeq technology and used a clustering‐free Divisive Amplicon Denoising Algorithm to infer ribosomal sequence variants. Data were analysed via non‐metric multidimensional scaling, Mantel tests and permutational multivariate analysis of variance. Binary and quantitative null models were used to determine whether results significantly deviated from random. Host genotype was determined by genotyping at 18 microsatellite loci and standard genetic analysis was performed in the R package APE.ResultsSignificant differences in fungal community composition were detected on either side of Wallace's line (p = <.001 R2 = .040). A significant distance decay of similarity pattern was observed between ribosomal sequence variants and geographical distance (p = .001 R2 = .227) and several fungal ribosomal sequence variants were significantly associated with sampling sites found either east or west of Wallace's line.Main conclusionsFungi are generally considered to have excellent dispersal potentials and marine fungi have the potential to disperse far and wide in an environment that has no obvious barriers to dispersal. Despite this assumed excellent dispersal potential, we show that fungal communities on either side of Wallace's line are significantly different from one another. We speculate that limited dispersal and differences in habitat type are responsible for the observed pattern. Work examining biogeographical patterns in marine fungi is still in its infancy and further research is required to fully understand marine fungal biogeography.

Fungal Community Assembly in the Amazonian Dark Earth.

Here, we compare the fungal community composition and diversity in Amazonian Dark Earth (ADE) and the respective non-anthropogenic origin adjacent (ADJ) soils from four different sites in Brazilian Central Amazon using pyrosequencing of 18S ribosomal RNA (rRNA) gene. Fungal community composition in ADE soils were more similar to each other than their ADJ soils, except for only one site. Phosphorus and aluminum saturation were the main soil chemical factors contributing to ADE and ADJ fungal community dissimilarities. Differences in fungal richness were not observed between ADE and ADJ soil pairs regarding to the most sites. In general, the most dominant subphyla present in the soils were Pezizomycotina, Agaricomycotina, and Mortierellomycotina. The most abundant operational taxonomic units (OTUs) in ADE showed similarities with the entomopathogenic fungus Cordyceps confragosa and the saprobes Fomitopsis pinicola, Acremonium vitellinum, and Mortierellaceae sp., whereas OTUs similar to Aspergillus niger, Lithothelium septemseptatum, Heliocephala gracillis, and Pestalosphaeria sp. were more abundant in ADJ soils. Differences in fungal community composition were associated to soil chemical factors in ADE (P, Ca, Zn, Mg, organic matter, sum of bases, and base saturation) and ADJ (Al, potential acidity, Al saturation, B, and Fe) soils. These results contribute to a deeper view of the fungi communities in ADE and open new perspectives for entomopathogenic fungi studies.Electronic supplementary materialThe online version of this article (doi:10.1007/s00248-015-0703-7) contains supplementary material, which is available to authorized users.

The Distribution and Identity of Edaphic Fungi in the McMurdo Dry Valleys.

Contrary to earlier assumptions, molecular evidence has demonstrated the presence of diverse and localized soil bacterial communities in the McMurdo Dry Valleys of Antarctica. Meanwhile, it remains unclear whether fungal signals so far detected in Dry Valley soils using both culture-based and molecular techniques represent adapted and ecologically active biomass or spores transported by wind. Through a systematic and quantitative molecular survey, we identified significant heterogeneities in soil fungal communities across the Dry Valleys that robustly correlate with heterogeneities in soil physicochemical properties. Community fingerprinting analysis and 454 pyrosequencing of the fungal ribosomal intergenic spacer region revealed different levels of heterogeneity in fungal diversity within individual Dry Valleys and a surprising abundance of Chytridiomycota species, whereas previous studies suggested that Dry Valley soils were dominated by Ascomycota and Basidiomycota. Critically, we identified significant differences in fungal community composition and structure of adjacent sites with no obvious barrier to aeolian transport between them. These findings suggest that edaphic fungi of the Antarctic Dry Valleys are adapted to local environments and represent an ecologically relevant (and possibly important) heterotrophic component of the ecosystem.

Fungal community structure in disease suppressive soils assessed by 28S LSU gene sequencing.

Natural biological suppression of soil-borne diseases is a function of the activity and composition of soil microbial communities. Soil microbe and phytopathogen interactions can occur prior to crop sowing and/or in the rhizosphere, subsequently influencing both plant growth and productivity. Research on suppressive microbial communities has concentrated on bacteria although fungi can also influence soil-borne disease. Fungi were analyzed in co-located soils ‘suppressive’ or ‘non-suppressive’ for disease caused by Rhizoctonia solani AG 8 at two sites in South Australia using 454 pyrosequencing targeting the fungal 28S LSU rRNA gene. DNA was extracted from a minimum of 125 g of soil per replicate to reduce the micro-scale community variability, and from soil samples taken at sowing and from the rhizosphere at 7 weeks to cover the peak Rhizoctonia infection period. A total of ∼994,000 reads were classified into 917 genera covering 54% of the RDP Fungal Classifier database, a high diversity for an alkaline, low organic matter soil. Statistical analyses and community ordinations revealed significant differences in fungal community composition between suppressive and non-suppressive soil and between soil type/location. The majority of differences associated with suppressive soils were attributed to less than 40 genera including a number of endophytic species with plant pathogen suppression potentials and mycoparasites such as Xylaria spp. Non-suppressive soils were dominated by Alternaria, Gibberella and Penicillum. Pyrosequencing generated a detailed description of fungal community structure and identified candidate taxa that may influence pathogen-plant interactions in stable disease suppression.

Effect of genetic modification of potato starch on decomposition of leaves and tubers and on fungal decomposer communities

As part of a risk evaluation of growing genetically modified crops, we investigated the effects of a genetic modification of starch quality (increased level of amylopectin) in potato tubers (Solanum tuberosum L.) on the decomposition of tissues (tubers and leaves) as well as on the associated fungal functional and phylogenetic diversity. The weight loss of both leaves and tubers in litterbags was analysed after 1, 3 and 6 months of incubation in soils and combined with measurements of fungal extracellular enzyme activities (laccases, Mn-peroxidases and cellulases) as well as molecular analyses of the fungal community (ITS regions and cellobiohydrolase I (cbhI) genes). The study revealed that initial (after one month) decomposition of both tubers and leaves of the parental isoline was significantly faster than that of the genetically modified (GM)-variety. This coincided with differences in fungal community composition. After this initial difference, no significant differences in any of the parameters measured could be detected after 3 and 6 months of decomposition illustrating the transient nature of the initial difference between the cultivars. Thus, it can be concluded that the starch modified tubers are not harmful to the fungal decomposer community and that despite initial differences in decomposition, the final decomposition rate of tissues from the GM-variety was similar to that of tissues from the parental variety. Furthermore, interesting dynamics of fungal phyla and species during decomposition were observed; the basidiomycetal yeasts and ascomycetes were primary colonizers of the potato tissue while basidiomycetes were dominant in the more decomposed and lignin-rich litter.

Diversity of fungi in hair roots of Ericaceae varies along a vegetation gradient

Ericaceous dwarf shrubs including Calluna vulgaris and Vaccinium spp. occur both in open heathland communities and in forest ecosystems as understory vegetation. Ericaceous shrubs were once thought to form ericoid mycorrhizal associations with a relatively narrow range of ascomycetous fungi closely related to, and including, Rhizoscyphus ericae. However, perceptions have recently changed since the realization that a broader range of ascomycete fungi, and in some cases basidiomycete fungi, can also form associations with the roots of ericaceous plants. We used a combination of molecular approaches, including denaturing gradient gel electrophoresis, terminal restriction fragment length polymorphism, cloning and sequencing, to investigate the diversity of fungi associated with C. vulgaris roots collected across a heathland/native Scots pine forest vegetation gradient. We also determined differences in fungal community composition between roots of co-occurring C. vulgaris and Vaccinium myrtillus in the forest understory. Collectively, the data show that a large diversity of potentially ericoid mycorrhizal fungal taxa associate with roots of C. vulgaris and V. myrtillus, and that ascomycetes were about 2.5 times more frequent than basidiomycetes. The assemblages of fungi associated with C. vulgaris and V. myrtillus were different. In addition, the community of fungi associated with C. vulgaris hair roots was different for samples collected from the forest, open heathland and a transition zone between the two. This separation was partly, but not entirely, due to the occurrence of typical ectomycorrhizal basidiomycetes associated with the hair roots of C. vulgaris in the forest understory. These data demonstrate that forest understory ericaceous shrubs associate with a diverse range of ascomycete and basidiomycete taxa, including typical ectomycorrhizal basidiomycetes.

Elephant dung decomposition and coprophilous fungi in two habitats of semi-arid Botswana

In order to understand the impact of habitat changes on ecosystem processes caused by increased populations of elephants, elephant dung decomposition was studied in semi-arid Botswana. Dung decomposition rates were studied with and without the presence of arthropods, using pairs of exposed dung and dung enclosed in nylon-mesh bags, respectively. Dung decomposition rates were lower in the absence of arthropods. The rates in the late wet season were higher in the scrubland than in the woodland. In the early dry season, immediately after the wet season, the rates were higher in the woodland than in the scrubland. The difference in decomposition rates between habitats was attributed to microclimatic conditions created by vegetation cover. With regard to fungal succession, Cladosporium cladosporioides and Eurotium brefeldianum occurred only in the late stages of dung decomposition whereas Talaromyces helicus, Cercophora coprophila and Sporormiella minima occurred in all the stages. Although there was no significant difference in Shannon–Weiner fungal species diversity index between habitats, seasons, dung ages and laboratory incubation periods, there were significant differences in fungal community composition between these parameters. Species richness was higher in the late wet season than in the early dry season, indicating the importance of moist conditions for a large diversity of fungal species.

Effect of tree host species on fungal community composition in a tropical rain forest in Panama

Abstract. To determine whether host species influence the composition of fungal communities, the ascomycetes and basidiomycetes present on three tree species (Prioria copaifera (Fabaceae), Quararibea asterolepis (Bombacaceae), and Trichilia tuberculata (Meliaceae)) were sampled on the 50‐ha Forest Dynamics Project plot in lowland moist tropical forest on Barro Colorado Island, Panama. The most abundant fungal morphotypes of both ascomycetes and basidiomycetes were generalists found on all three hosts, but detrended correspondence analysis revealed distinct differences in fungal community composition among host trees. These differences among hosts were constant across census years. Randomization tests revealed that there were significantly fewer host‐generalist fungi than expected for ascomycetes but not for basidiomycetes. These results indicate that host composition plays a role in structuring both ascomycete and basidiomycete fungal communities, but that the most successful fungal morphotypes are capable of colonizing multiple host species.