Ectomycorrhizal and Saprotrophic Fungal Communities Vary Across mm-Scale Soil Microsites Differing in Phosphatase Activity

To understand nutrient cycling in soils, soil processes and microorganisms need be better characterized. To determine whether specific trophic groups of fungi are associated with soil enzyme activity, we used soil imprinting to guide mm-scale sampling from microsites with high and low phosphatase activities in birch/Douglas-fir stands. Study 1 involved sampling one root window per site at 12 sites of different ages(stands);study 2 was conducted at one of the stem-exclusion stands, at which 5 root windows had been installed. Total fungal and ectomycorrhizal(EM) fungal terminal-restriction fragment length polymorphism(TRFLP)fingerprints differed between high-and low-phosphatase activity microsites at 8 of 12 root windows across 12 sites. Where differences were detected, fewer EM fungi were detected in high-than low-phosphatase activity microsites. Using 5 root windows at one site,next-generation sequencing detected similar fungal communities across microsites, but the ratio of saprotrophic to EM fungal reads was higher in high-phosphatase activity microsites in the two windows that had low EM fungal richness. In windows with differences in fungal communities, both studies indicated that EM fungi were less successful than saprotrophic fungi in colonizing fine-scale,organic matter-rich microsites. Fine-scale sampling linked with in situ detection of enzyme activity revealed relationships between soil fungal communities and phosphatase activity that could not be observed at the scales employed by conventional approaches, thereby contributing to the understanding of fine-scale phosphorus cycling in forest soils.

Fungal diversity and community composition responses to the reintroduction of fire in a non-managed Mediterranean shrubland ecosystem

Background:More than a decade of fire suppression has changed the structure of fire-adapted shrubland ecosystems in Spain’s National Parks,which are now at extreme risk of uncontrolled wildfires.Prescribed burning can mitigate the risk of wildfires by reducing the fuel load but prescribed burning may also alter the soil properties and reduce microbial and fungal activity,causing changes in the availability of nutrients deep in the soil layer.Although fungal communities are a vital part of post-fire restoration,some fire effects remain unclear.To examine the short-term effects of prescribed burning on soil fungal communities in Doñana Biological Reserve(SW Spain),we collected soil samples pre-burn and 1 day,6 and 12 months post-burn from burned plots to perform physicochemical and metabarcode DNA analyses.Results:Prescribed burning had no significant effect on the total fungal operational taxonomic unit richness and abundance.However,changes in soil pH,nitrogen and potassium content post-burn affected fungal community composition.Small non-significant changes in pH and phosphorous affected the composition of ectomycorrhizal fungi.Conclusions:The ectomycorrhizal fungal community appears to be resilient to the effects of low-to moderate-intensity fires and saprotrophic taxa may benefit from this kind of fire.This finding revealed that prescribed burning is a potentially valuable management tool for reducing fire hazards in shrublands that has little effect on the total richness and abundance of fungal communities.

Soil fungal community is more sensitive to nitrogen deposition than increased rainfall in a mixed deciduous forest of China

Nitrogen(N)deposition and intensified rainfall can strongly affect soil microbial community,but compared with available studies on bacteria,those on soil fungi are quite limited.Here we carried out a field experiment in a mixed deciduous forest of China to study the influences of increased N deposition and rainfall on soil fungi by using quantitative PCR and high-throughput sequencing method.The results demonstrated that(1)N addition significantly increased fungal abundance and alpha diversity(richness,Shannon index and Invsimpson index),changed fungal community composition at OTU level,and marginally increased the relative abundance of Ascomycota and Zygomycota,while water addition showed no remarkable effects on fungal abundance,biodiversity and community composition.(2)N addition significantly increased the richness of saprotrophic fungi and pathogenic fungi,and the relative abundance of saprotrophic fungi,but water addition only slightly increased the abundance of pathogenic fungi.(3)Fungal composition dissimilarity closely correlated with the disparity of soil parameters as a whole.Soil NH_(4)^(+)-N exhibited strong positive correlation with the richness of pathogenic fungi and mycorrhizal fungi,while both soil moisture and NH_(4)^(+)-N tightly correlated with soil fungal abundance and alpha diversity indices.We concluded that in this N-limited but non-water-limited forest ecosystem,N deposition posed stronger effects on soil fungi than increased rainfall,partially mediated by changes in soil properties.

Soil fungal and prokaryotic community structure exhibits differential short-term responses to timber harvest in the Pacific Northwest

Conventional clear-cut timber harvest is a widespread industrial practice across the Pacific Northwest;however,information regarding how these practices impact soil microbial community structure at the regional scale is limited.With evidence of consistent and substantial impact of harvest on soil microbial functional profiles across the region(despite a range of environmental conditions),the objective of this study was to determine the extent to which harvest also influences the structure of prokaryotic and fungal soil microbial communities,and how generalized these trends are throughout the geographic region.Paired soil samples were collected one year before and after harvest across nine second-growth Douglas-fir forests in the Pacific Northwest.Total community DNA was extracted from the soils,and high-throughput targeted gene sequencing of the 16 S r RNA gene for prokaryotes and the internal transcribed spacer(ITS)gene for fungi was performed.Alpha diversity was consistently and significantly higher after harvest;it was moderately so for fungal communities(+14.6%),but only marginally so for prokaryotic communities(+2.0%).Similarly,on average,a greater proportion of the variation in the community structure of fungi(20.1%)at each site was associated with forest harvest compared to that of prokaryotes(13.2%).Overall,the greatest influence of timber harvest on soil microbial communities appeared to be a relative depletion of ectomycorrhizal fungi,with a concomitant enrichment of saprotrophic fungi.Understanding the short-term responses of soil microbial communities across the region,particularly those of tree root-associated symbionts,may aid our understanding of the role soil microbial communities play in ecological succession.

The Caucasian corticioid fungi:level of endemism,similarity,and possible contribution to European fungal diversity

We assess the composition of corticioid fungi in the Caucasus region for the first time.The Caucasian corticioids were compared with those of well-documented areas in the Northern Hemisphere using the Tripartite similarity index and cluster analysis.To investigate the significance of the Caucasus region as a possible contributor to the colonization of wood-inhabiting basidiomycetes in Europe,DNA sequences of nuclear ribosomal internal transcribed spacers(ITS1 and ITS2)belonging to the corticioid fungus Peniophorella praetermissa were analysed for comparisons of genetic diversity within and differentiation between geographical regions.Putative species endemism and disjunction of corticioids in the Caucasus region is also discussed.The composition of corticioid fungi in the Caucasus region was found to be distinctly more similar to Europe and North America than to East Asia and India.Similarity tests and molecular Fsts both point to a strong connection between the Caucasus and Europe.The highest molecular diversity in P.praetermissa was in the Caucasus and East Asia as compared with other regions studied.The Caucasus and East Asia were significantly differentiated from each other,and unlike Caucasian samples,East Asian sequences were highly divergent from the European ones.This result suggests that the Caucasus might have been a source of colonization for Europe.Endemism is very low,possibly a common feature for wood-inhabiting saprotrophic fungi.

Fungal diversity and its mechanism of community shaping in the milieu of sanitary landfill

Land filling is the main method to dispose municipal solid waste in China.During the decomposition of organic waste in landfills,fungi play an important role in organic carbon degradation and nitrogen cycling.However,fungal composition and potential functions in landfill have not yet been characterized.In this study,refuse and leachate samples with different areas and depths were taken from a large sanitary landfill in Beijing to identify fungal communities in landfills.In high-throughput sequencing of ITS region,474 operational taxonomic units(OTUs)were obtained from landfill samples with a cutoff level of 3%and a sequencing depth of 19962.The results indicates that Ascomycota,with the average relative abundance of 84.9%,was the predominant phylum in landfill fungal communities.At the genus level,Family Hypocreaceae unclassified(15.7%),Fusarium(9.9%)and Aspergillus(8.3%)were the most abundant fungi found in the landfill and most of them are of saprotrophic lifestyle,which plays a big role in nutrient cycling in ecosystem.Fungi existed both in landfilled refuse and leachate while both the richness and evenness of fungal communities were higher in the former.In addition,fungal communities in landfilled refuse presented geographic variances,which could be partly attributed to physical habitat properties(pH,dissolved organic carbon,volatile solid,NH_(4)^(+),NO_(2)^(−)and NO_(3)^(−)),while NO_(3)^(−)was considered the most significant factor(p<0.05)in shaping fungal community.

Biodiversity of fungi on Vitis vinifera L. revealed by traditional and high-resolution culture-independent approaches

This study is unique as it compares traditional and high-resolution culture-independent approaches using the same set of samples to study the saprotrophic fungi on Vitis vinifera.We identified the saprotrophic communities of table grape(Red Globe)and wine grape(Carbanate Gernischet)in China using both traditional and culture-independent techniques.The traditional approach used direct observations based on morphology,single spore isolation and phylogenetic analysis yielding 45 taxa which 19 were commonly detected in both cultivars.The same set of samples were then used for Illumina sequencing which analyzed ITS1 sequence data and detected 226 fungal OTUs,of which 176 and 189 belong to the cultivars Carbanate Gernischet and Red Globe,respectively.There were 139 OTUs shared between the two V.vinifera cultivars and 37 and 50 OTUs were specific to Carbanate Gernischet and Red Globe cultivars respectively.In the Carbanate Gernischet cultivar,Ascomycota accounted for 77%of the OTUs and in Red Globe,almost all sequenced were Ascomycota.The fungal taxa overlap at the genus and species level between the traditional and culture-independent approach was relatively low.In the traditional approach we were able to identify the taxa to species level,while in the culture-independent method we were frequently able to identify the taxa to family or genus level.This is remarkable as we used the same set of samples collected in China for both approaches.We recommend the use of traditional techniques to accurately identify taxa.Culture-independent method can be used to get a better understanding about the organisms that are present in a host in its natural environment.We identified primary and secondary plant pathogens and endophytes in the saprotrophic fungal communities,which support previous observations,that dead plant material in grape vineyards can be the primary sources of disease.Finally,based on present and previous findings,we provide a worldwide checklist of 905 fungal taxa on Vitis species,which includes their mode of life and distribution.