全球表层土壤中微生物群落的结构及功能

土壤中存在着地球上最多样化的微生物群落,它们对地球养分循环和碳储存都至关重要。为了更好的了解土壤功能,对土壤微生物的全球分布模式和功能基因序列进行建模,并了解土壤中细菌和真菌群落的多样性和结构之间的生物、环境联系是很有必要的。

Plant and fungal species interactions differ between aboveground and belowground habitats in mountain forests of eastern China

Plant and fungal species interactions drive many essential ecosystem properties and processes;however,how these interactions differ between aboveground and belowground habitats remains unclear at large spatial scales.Here,we surveyed 494 pairwise fungal communities in leaves and soils by Illumina sequencing,which were associated with 55 woody plant species across more than 2,000-km span of mountain forests in eastern China.The relative contributions of plant,climate,soil and space to the variation of fungal communities were assessed,and the plant-fungus network topologies were inferred.Plant phylogeny was the strongest predictor for fungal community composition in leaves,accounting for 19.1%of the variation.In soils,plant phylogeny,climatic factors and soil properties explained 9.2%,9.0%and 8.7%of the variation in soil fungal community,respectively.The plant-fungus networks in leaves exhibited significantly higher specialization,modularity and robustness(resistance to node loss),but less complicated topology(e.g.,significantly lower linkage density and mean number of links)than those in soils.In addition,host/fungus preference combinations and key species,such as hubs and connectors,in bipartite networks differed strikingly between aboveground and belowground samples.The findings provide novel insights into cross-kingdom(plant-fungus)species co-occurrence at large spatial scales.The data further suggest that community shifts of trees due to climate change or human activities will impair aboveground and belowground forest fungal diversity in different ways.

High-level classification of the Fungi and a tool for evolutionary ecological analyses

High-throughput sequencing studies generate vast amounts of taxonomic data.Evolutionary ecological hypotheses of the recovered taxa and Species Hypotheses are difficult to test due to problems with alignments and the lack of a phylogenetic backbone.We propose an updated phylum-and class-level fungal classification accounting for monophyly and divergence time so that the main taxonomic ranks are more informative.Based on phylogenies and divergence time estimates,we adopt phylum rank to Aphelidiomycota,Basidiobolomycota,Calcarisporiellomycota,Glomeromycota,Entomophthoromycota,Entorrhizomycota,Kickxellomycota,Monoblepharomycota,Mortierellomycota and Olpidiomycota.We accept nine subkingdoms to accommodate these 18 phyla.We consider the kingdom Nucleariae(phyla Nuclearida and Fonticulida)as a sister group to the Fungi.We also introduce a perl script and a newick-formatted classification backbone for assigning Species Hypotheses into a hierarchical taxonomic framework,using this or any other classification system.We provide an example of testing evolutionary ecological hypotheses based on a global soil fungal data set.

FungalTraits:a user-friendly traits database of fungi and fungus-like stramenopiles

The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies.Over the past decades,rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats.Yet,in spite of the progress of molecular methods,knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging.In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels.Combining the information from previous efforts such as FUNGuild and FunFun together with involvement of expert knowledge,we reannotated 10,210 and 151 fungal and Stramenopila genera,respectively.This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera,designed for rapid functional assignments of environmental stud-ies.In order to assign the trait states to fungal species hypotheses,the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences.On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1%dissimilarity threshold.

Identifying the ‘unidentified’ fungi: a global-scale long-read third-generation sequencing approach

Molecular identification methods,in particular high-throughput sequencing tools,have greatly improved our knowledge about fungal diversity and biogeography,but many of the recovered taxa from natural environments cannot be identified to species or even higher taxonomic levels.This study addresses the phylogenetic placement of previously unrecognized fungal groups by using two complementary approaches:(i)third-generation amplicon sequencing analysis of DNA from global soil samples,screening out ITS reads of<90%similarity to other available Sanger sequences,and(ii)analysis of common fungal taxa that were previously indicated to be enigmatic in terms of taxonomic placement based on the ITS sequences alone(so-called top50 sequences).For the global soil samples,we chose to amplify the full rRNA gene operon using four partly overlapping amplicons and multiple newly developed primers or primer combinations that cover nearly all fungi and a vast majority of non-fungal eukaryotes.We extracted the rRNA 18S(SSU)and 28S(LSU)genes and performed phylogenetic analyses against carefully selected reference material.Both SSU and LSU analyses placed most soil sequences and top50 sequences to known orders and classes,but tens of monophyletic groups and single sequences remained outside described taxa.Furthermore,the LSU analyses recovered a few small groups of sequences that may potentially represent novel phyla.We conclude that rRNA genes-based phylogenetic analyses are efficient tools for determining phylogenetic relationships of fungal taxa that cannot be placed to any order or class using ITS sequences alone.However,in many instances,longer rRNA gene sequences and availability of both SSU and LSU reads are needed to improve taxonomic resolution.By leveraging third-generation sequencing from global soil samples,we successfully provided phylogenetic placement for many previously unidentified sequences and broadened our view on the fungal tree of life,with 10-20%new order-level taxa.In addition,the PacBio sequence data greatly extends fungal class-level information in reference databases.

Improving ITS sequence data for identification of plant pathogenic fungi

Plant pathogenic fungi are a large and diverse assemblage of eukaryotes with substantial impacts on natural ecosystems and human endeavours.These taxa often have complex and poorly understood life cycles,lack observable,discriminatory morphological characters,and may not be amenable to in vitro culturing.As a result,species identification is frequently difficult.Molecular(DNA sequence)data have emerged as crucial information for the taxonomic identification of plant pathogenic fungi,with the nuclear ribosomal internal transcribed spacer(ITS)region being the most popular marker.However,international nucleotide sequence databases are accumulating numerous sequences of compromised or low-resolution taxonomic annotations and substandard technical quality,making their use in the molecular identification of plant pathogenic fungi problematic.Here we report on a concerted effort to identify high-quality reference sequences for various plant pathogenic fungi and to re-annotate incorrectly or insufficiently annotated public ITS sequences from these fungal lineages.A third objective was to enrich the sequences with geographical and ecological metadata.The results-a total of 31,954 changes-are incorporated in and made available through the UNITE database for molecular identification of fungi(http://unite.ut.ee),including standalone FASTA files of sequence data for local BLAST searches,use in the next-generation sequencing analysis platforms QIIME and mothur,and related applications.The present initiative is just a beginning to cover the wide spectrum of plant pathogenic fungi,and we invite all researchers with pertinent expertise to join the annotation effort.

Delimiting species in Basidiomycota:a review

Species delimitation is one of the most fundamental processes in biology.Biodiversity undertakings,for instance,require explicit species concepts and criteria for species delimitation in order to be relevant and translatable.However,a perfect species concept does not exist for Fungi.Here,we review the species concepts commonly used in Basidiomycota,the second largest phylum of Fungi that contains some of the best known species of mushrooms,rusts,smuts,and jelly fungi.In general,best practice is to delimitate species,publish new taxa,and conduct taxonomic revisions based on as many independent lines of evidence as possible,that is,by applying a so-called unifying(or integrative)conceptual framework.However,the types of data used vary considerably from group to group.For this reason we discuss the different classes of Basidiomycota,and for each provide:(i)a general introduction with difficulties faced in species recognition,(ii)species concepts and methods for species delimitation,and(iii)community recommendations and conclusions.

The Global Soil Mycobiome consortium dataset for boosting fungal diversity research

Fungi are highly important biotic components of terrestrial ecosystems,but we still have a very limited understanding about their diversity and distribution.This data article releases a global soil fungal dataset of the Global Soil Mycobiome consortium(GSMc)to boost further research in fungal diversity,biogeography and macroecology.The dataset comprises 722,682 fungal operational taxonomic units(OTUs)derived from PacBio sequencing of full-length ITS and 18S-V9 variable regions from 3200 plots in 108 countries on all continents.The plots are supplied with geographical and edaphic metadata.The OTUs are taxonomically and functionally assigned to guilds and other functional groups.The entire dataset has been corrected by excluding chimeras,index-switch artefacts and potential contamination.The dataset is more inclusive in terms of geographical breadth and phylogenetic diversity of fungi than previously published data.The GSMc dataset is available over the PlutoF repository.

Correction to:FungalTraits:a user friendly traits database of fungi and fungus-like stramenopiles

Correction to:Fungal Diversity(2020)105:116 https://doi.org/10.1007/s13225-020-00466-2 There were errors in the name of author LászlóG.Nagy and in affiliation no.31 in the original publication.The original article has been corrected.