How to know the fungi: combining field inventories and DNA-barcoding to document fungal diversity

Why Are There So Few Basidiomycota and Basal Fungi as Endophytes? A Review

A review of selected studies on fungal endophytes confirms the paucity of Basidiomycota and basal fungi, with almost 90% attributed to Ascomycota. Reasons for the low number of Basidiomycota and basal fungi, including the Chytridiomycota, Mucoromycota, and Mortierellomycota, are advanced, including isolation procedure and media, incubation period and the slow growth of basidiomycetes, the identification of non-sporulating isolates, endophyte competition, and fungus-host interactions. We compare the detection of endophytes through culture-dependent methods and culture-independent methods, the role of fungi on senescence of the host plant, and next-generation studies.

Preliminary species diversity and community phylogenetics of wood-inhabiting basidiomycetous fungi in the Dabie Mountains, Central China reveal unexpected richness

Wood-inhabiting fungi have important economic values as well as playing a major ecological role in forest ecosystem cycles. The Dabie Mountains, at the junction of Henan, Hubei, and Anhui Provinces, Central China, provide an ideal climate and favorable niches for the speciation and diversification of various forms of life including fungi. We studied the species diversity and community phylogenetics of wood-inhabiting basidiomycetous fungi that revealed 175 wood-inhabiting basidiomycetous species, of which 20 represented unidentified species, based on morphological and phylogenetic analyses of 575 specimens collected from ten sampling sites. These species belonged to two classes, 11 orders, 42 families, and 106 genera of Basidiomycota, and included 12 edible species, 28 medicinal species, four poisonous species, and seven forest pathogens. Four types of fungal distribution pattern at the genus level were recognized for 65 genera, while another 41 genera could not be placed in any known distribution pattern. The five sampling sites in the eastern part of the Dabie Mountains had significantly higher species diversity and phylogenetic diversity of wood-inhabiting basidiomycetous fungi than those in the western part, and thus deserve priority in terms of conservation. The community of wood-inhabiting basidiomycetous fungi in the Dabie Mountains is generally affected by a combination of habitat filtering and competitive exclusion. This study provides a basis on which to build actions for the comprehensive recognition, utilization, and conservation of wood-inhabiting basidiomycetous fungi in the region.

New species of Hydnotrya (Ascomycota, Pezizomycetes) from southwestern China with notes on morphological characteristics of 17 species of Hydnotrya

More specimens of Hydnotrya have been collected from southwestern China in recent years. Morphological and molecular analyses showed that they belonged to three species of Hydnotrya, of which two are new to science, H.oblongispora and H.zayuensis. The third one was H.laojunshanensis, previously reported in 2013. The new species are described, and their relationship to other species of Hydnotrya is discussed. H.laojunshanensis is re-described in more detail. The main morphological characters of 17 species of Hydnotrya are compared and a key to them is provided as well.

Five new species of Gloeandromyces (Fungi, Laboulbeniales) from tropical American bat flies (Diptera, Streblidae), revealed by morphology and phylogenetic reconstruction

This paper describes and illustrates five new species of Gloeandromyces (Ascomycota, Laboulbeniales) associated with tropical American bat flies (Diptera, Streblidae). These are Gloeandromyces cusucoensis sp. nov. from Trichobius uniformis in Costa Rica and Honduras, G. diversiformis sp. nov. from Strebla wiedemanni in Costa Rica, G. plesiosaurus sp. nov. from Trichobius yunkeri in Panama, G. pseudodickii sp. nov. from Trichobius longipes in Ecuador and Panama, and G. verbekeniae sp. nov. from Strebla galindoi in Ecuador and Panama. The description of these five species doubles the number of known species in the genus. Morphological characteristics, host association, and a three-locus (18S nuc rDNA, 28S nuc rDNA, TEF1) phylogenetic reconstruction support placement of these taxa in the genus Gloeandromyces. Three of the new species are polymorphic; they have multiple morphotypes that grow in specific positions on the host integument: G. diversiformis f. diversiformis, f. musiformis, and f. vanillicarpiformis; G. plesiosaurus f. asymmetricus and f. plesiosaurus; and G. verbekeniae f. verbekeniae and f. inflexus. Finally, a dichotomous key to all species and morphotypes is presented.

Phylogeny and Taxonomic Revision of the Family Discinaceae (Pezizales, Ascomycota)

Species of Discinaceae are common macrofungi with a worldwide distribution. Some of them are commercially consumed, while a few others are reported as poisonous. Two genera were accepted in the family: the epigeous Gyromitra with discoid, cerebriform to saddle-shaped ascomata and the hypogeous Hydnotrya with globose or tuberous ascomata. However, due to discrepancies in their ecological behaviors, a comprehensive investigation of their relationship was not thoroughly explored. In this study, phylogenies of Discinaceae were reconstructed using sequence analyses of combined and separate three gene partitions (internal transcribed spacer [ITS], large subunit ribosomal DNA [LSU], and translation elongation factor [TEF]) with a matrix containing 116 samples. As a result, the taxonomy of the family was renewed. Eight genera were recognized: two of them (Gyromitra and Hydnotrya) were retained, three (Discina, Paradiscina, and Pseudorhizina) were revived, and three (Paragyromitra, Pseudodiscina, and Pseudoverpa) were newly established. Nine new combinations were made in four genera. Two new species in Paragyromitra and Pseudodiscina and an un-named taxon of Discina were described and illustrated in detail based on the materials collected from China. Furthermore, a key to the genera of the family was also provided. IMPORTANCE Taxonomy of the fungal family Discinaceae (Pezizales, Ascomycota) was significantly renewed on the basis of sequence analyses of internal transcribed spacer (ITS), large subunit ribosomal DNA (LSU), and translation elongation factor (TEF). Eight genera were accepted, including three new genera; two new species were described; and nine new combinations were made. A key to the accepted genera of the family is provided. The aim of this study is to deepen the understanding of the phylogenetic relationships among genera of the group, as well as the associated generic concepts.

Re-examination of the Southern Hemisphere truffle genus Amylascus (Pezizaceae, Ascomycota) and characterization of the sister genus Nothoamylascus gen. nov

Amylascus is a genus of ectomycorrhizal truffles within Pezizaceae that is known from Australia and contains only two described species, A. herbertianus and A. tasmanicus. Species of Amylascus are closely related to truffles (Pachyphlodes, Luteoamylascus) and cup fungi (Plicariella) from the Northern Hemisphere. Here we reevaluate the species diversity of Amylascus and related taxa from southern South America and Australia based on new morphological and molecular data. We identify previously undocumented diversity and morphological variability in ascospore color, ascospore ornamentation, hymenial construction, epithecium structure and the amyloid reaction of the ascus in Melzer's reagent. We redescribe two Amylascus species from Australia and describe seven new Amylascus species, five from South America and two from Australia. This is the first report of Amylascus species from South America. We also describe the new South American genus Nothoamylascus as sister lineage to the Pachyphlodes-Amylascus-Luteoamylascus clade (including Amylascus, Luteoamylascus, Pachyphlodes, and Plicariella). We obtained ITS sequences of mitotic spore mats from Nothoamylascus erubescens gen. & sp. nov. and four of the seven newly described Amylascus species, providing the first evidence of mitotic spore mats in Amylascus. Additional ITS sequences from mitotic spore mats reveal the presence of nine additional undescribed Amylascus and one Nothoamylascus species that do not correspond to any sampled ascomata. We also identify three additional undescribed Amylascus species based on environmental sequences from the feces of two grounddwelling bird species from Chile, Scelorchilus rubecula and Pteroptochos tarnii. Our results indicate that ascomata from Amylascus and Nothoamylascus species are rarely collected, but molecular data from ectomycorrhizal roots and mitotic spore mats indicate that these species are probably common and widespread in southern South America. Finally, we present a time-calibrated phylogeny that is consistent with a late Gondwanan distribution. The time since the most recent common ancestor of: 1) the family Pezizaceae had a mean of 276 Ma (217-337 HPD); 2) the Amylascus-Pachyphlodes-Nothoamylascus-Luteoamylascus clade had a mean of 79 Ma (60-100 HPD); and 3) the Amylascus-Pachyphlodes clade had a mean of 50 Ma (38-62 HPD). The crown age of Pachyphlodes had a mean of 39 Ma (25-42 HPD) and Amylascus had a mean age of 28 Ma (20-37 HPD), falling near the Eocene-Oligocene boundary and the onset of the Antarctic glaciation (c. 35 Ma). Citation: Healy RA, Truong C, Castellano MA, et al. 2023. Re-examination of the Southern Hemisphere truffle genus Amylascus (Pezizaceae, Ascomycota) and characterization of the sister genus Nothoamylascus gen. nov. Persoonia 51: 125-151. doi: 10.3767/persoonia.2023.51.03.

Local adaptation in fungi

In this review, I explore the pervasive but underappreciated role of local adaptation in fungi. It has been difficult historically to study local adaptation in fungi because of the limited understanding of fungal species and their traits, but new hope has been offered with technological advances in sequencing. The filamentous nature of fungi invalidates some assumptions made in evolution because of their ability to exist as multinucleate entities with genetically different nuclei sharing the same cytoplasm. Many insights on local adaptation have come from studying fungi, and much of the empirical evidence gathered about local adaptation in the context of host-pathogen interactions comes from studying fungal virulence genes, drug resistance, and environmental adaptation. Together, these insights paint a picture of the variety of processes involved in fungal local adaptation and their connections to the unusual cell biology of Fungi (multinucleate, filamentous habit), but there is much that remains unknown, with major gaps in our knowledge of fungal species, their phenotypes, and the ways by which they adapt to local conditions.

Diversity and distribution of tropical ectomycorrhizal fungi

The tropics were long considered to have few ectomycorrhizal fungi, presumably due to a paucity of ectomycorrhizal host plants relative to higher-latitude ecosystems. However, an increase in research in tropical regions over the past 30 years has greatly expanded knowledge about the occurrence of tropical ectomycorrhizal fungi. To assess their broad biogeographic and diversity patterns, we conducted a comprehensive review and quantitative data analysis of 49 studies with 80 individual data sets along with additional data from GlobalFungi to elucidate tropical diversity patterns and biogeography of ectomycorrhizal fungi across the four main tropical regions: the Afrotropics, the Neotropics, Southeast Asia, and Oceania. Generalized linear models were used to explore biotic and abiotic influences on the relative abundance of the 10 most frequently occurring lineages. We also reviewed the available literature and synthesized current knowledge about responses of fungi to anthropogenic disturbances, and their conservation status and threats. We found that /russula-lactarius and /tomentella-thelephora were the most abundant lineages in the Afrotropics, the Neotropics, and Southeast Asia, whereas /cortinarius was the most abundant lineage in Oceania, and that /russula-lactarius, /inocybe, and /tomentella-thelephora were the most species-rich lineages across all of the tropical regions. Based on these analyses, we highlight knowledge gaps for each tropical region. Increased sampling of tropical regions, collaborative efforts, and use of molecular methodologies are needed for a more comprehensive view of the ecology and diversity of tropical ectomycorrhizal fungi.

50 Years of Cumulative Open-Source Data Confirm Stable and Robust Biodiversity Distribution Patterns for Macrofungi

Fungi are a hyper-diverse kingdom that contributes significantly to the regulation of the global carbon and nutrient cycle. However, our understanding of the distribution of fungal diversity is often hindered by a lack of data, especially on a large spatial scale. Open biodiversity data may provide a solution, but concerns about the potential spatial and temporal bias in species occurrence data arising from different observers and sampling protocols challenge their utility. The theory of species accumulation curves predicts that the cumulative number of species reaches an asymptote when the sampling effort is sufficiently large. Thus, we hypothesize that open biodiversity data could be used to reveal large-scale macrofungal diversity patterns if these datasets are accumulated long enough. Here, we tested our hypothesis with 50 years of macrofungal occurrence records in Norway and Sweden that were downloaded from the Global Biodiversity Information Facility (GBIF). We first grouped the data into five temporal subsamples with different cumulative sampling efforts (i.e., accumulation of data for 10, 20, 30, 40 and 50 years). We then predicted the macrofungal diversity and distribution at each subsample using the maximum entropy (MaxEnt) species distribution model. The results revealed that the cumulative number of macrofungal species stabilized into distinct distribution patterns with localized hotspots of predicted macrofungal diversity with sampling efforts greater than approximately 30 years. Our research demonstrates the utility and importance of the long-term accumulated open biodiversity data in studying macrofungal diversity and distribution at the national level.

Beyond Nuclear Ribosomal DNA Sequences: Evolution, Taxonomy, and Closest Known Saprobic Relatives of Powdery Mildew Fungi (Erysiphaceae) Inferred From Their First Comprehensive Genome-Scale Phylogenetic Analyses

Powdery mildew fungi (Erysiphaceae), common obligate biotrophic pathogens of many plants, including important agricultural and horticultural crops, represent a monophyletic lineage within the Ascomycota. Within the Erysiphaceae, molecular phylogenetic relationships and DNA-based species and genera delimitations were up to now mostly based on nuclear ribosomal DNA (nrDNA) phylogenies. This is the first comprehensive genome-scale phylogenetic analysis of this group using 751 single-copy orthologous sequences extracted from 24 selected powdery mildew genomes and 14 additional genomes from Helotiales, the fungal order that includes the Erysiphaceae. Representative genomes of all powdery mildew species with publicly available whole-genome sequencing (WGS) data that were of sufficient quality were included in the analyses. The 24 powdery mildew genomes included in the analysis represented 17 species belonging to eight out of 19 genera recognized within the Erysiphaceae. The epiphytic genera, all but one represented by multiple genomes, belonged each to distinct, well-supported lineages. Three hemiendophytic genera, each represented by a single genome, together formed the hemiendophytic lineage. Out of the 14 other taxa from the Helotiales, Arachnopeziza araneosa, a saprobic species, was the only taxon that grouped together with the 24 genome-sequenced powdery mildew fungi in a monophyletic clade. The close phylogenetic relationship between the Erysiphaceae and Arachnopeziza was revealed earlier by a phylogenomic study of the Leotiomycetes. Further analyses of powdery mildew and Arachnopeziza genomes may discover signatures of the evolutionary processes that have led to obligate biotrophy from a saprobic way of life. A separate phylogeny was produced using the 18S, 5.8S, and 28S nrDNA sequences of the same set of powdery mildew specimens and compared to the genome-scale phylogeny. The nrDNA phylogeny was largely congruent to the phylogeny produced using 751 orthologs. This part of the study has revealed multiple contamination and other quality issues in some powdery mildew genomes. We recommend that the presence of 28S, internal transcribed spacer (ITS), and 18S nrDNA sequences in powdery mildew WGS datasets that are identical to those determined by Sanger sequencing should be used to assess the quality of assemblies, in addition to the commonly used Benchmarking Universal Single-Copy Orthologs (BUSCO) values.

Molecular-Based Diversity Studies and Field Surveys Are Not Mutually Exclusive: On the Importance of Integrated Methodologies in Mycological Research

Understanding and describing the diversity of living organisms is a great challenge. Fungi have for a long time been, and unfortunately still are, underestimated when it comes to taxonomic research. The foundations were laid by the first mycologists through field observations. These important fundamental works have been and remain vital reference works. Nevertheless, a non-negligible part of the studied funga escaped their attention. Thanks to modern developments in molecular techniques, the study of fungal diversity has been revolutionized in terms of tools and knowledge. Despite a number of disadvantages inherent to these techniques, traditional field-based inventory work has been increasingly superseded and neglected. This perspective aims to demonstrate the central importance of field-based research in fungal diversity studies, and encourages researchers not to be blinded by the sole use of molecular methods.

Fungal diversity in the tropics: Entoloma spp. in Panama

Entoloma (Agaricales, Basidiomycota) is a species-rich genus with approximately 2000 species known worldwide. In Central America, however, information about the species of this genus is sparse, despite the generally high biodiversity in this region. Recently, 124 specimens of Entoloma were collected in Panama, Chiriquí Province. In the present publication, the morphology of 20 species represented by more than one specimen is described and depicted with photographs, line drawings, and scanning electron micrographs. Molecular phylograms based on ITS or concatenated ITS and partial nc LSU rDNA sequences are provided. The taxonomic status of these species is evaluated and 17 species of Entoloma are described as new to science. Only one species could be assigned to an already known species, viz. Entoloma belouvense. Nolanea albertinae, described from Brazil, appeared similar and is combined in E. belouvense on varietal level. The identifications of two further species are uncertain. At least 30 other species, including potentially new species, cannot formally be described due to insufficient material. A preliminary key to the species of the genus Entoloma in Panama is provided. The spatial shape of the polyhedroid basidiospores of Entoloma spp. is discussed based on literature and the micrographs generated for the present study. Our re-evaluations indicate that the type of polyhedroid basidiospore and the structure of its base are not reliable as diagnostic characters for the delimitation of subgenera in Entoloma.

Exploring the Relationships between Four New Species of Boletoid Fungi from Northern China and Their Related Species

The family Boletaceae primarily represents ectomycorrhizal fungi, which play an essential ecological role in forest ecosystems. Although the Boletaceae family has been subject to a relatively global and comprehensive history of work, novel species and genera are continually described. During this investigation in northern China, many specimens of boletoid fungi were collected. Based on the study of their morphology and phylogeny, four new species, Butyriboletus pseudoroseoflavus, Butyriboletus subregius, Tengioboletus subglutinosus, and Suillellus lacrymibasidiatus, are introduced. Morphological evidence and phylogenetic analyses of the single or combined dataset (ITS or 28S, rpb1, rpb2, and tef1) confirmed these to be four new species. The evidence and analyses indicated the new species’ relationships with other species within their genera. Detailed descriptions, color photographs, and line drawings are provided. The species of Butyriboletus in China were compared in detail and the worldwide keys of Tengioboletus and Suillellus were given.

Global Distribution and Richness of Armillaria and Related Species Inferred From Public Databases and Amplicon Sequencing Datasets

Armillaria is a globally distributed fungal genus most notably composed of economically important plant pathogens that are found predominantly in forest and agronomic systems. The genus sensu lato has more recently received attention for its role in woody plant decomposition and in mycorrhizal symbiosis with specific plants. Previous phylogenetic analyses suggest that around 50 species are recognized globally. Despite this previous work, no studies have analyzed the global species richness and distribution of the genus using data derived from fungal community sequencing datasets or barcoding initiatives. To assess the global diversity and species richness of Armillaria, we mined publicly available sequencing datasets derived from numerous primer regions for the ribosomal operon, as well as ITS sequences deposited on Genbank, and clustered them akin to metabarcoding studies. Our estimates reveal that species richness ranges from 50 to 60 species, depending on whether the ITS1 or ITS2 marker is used. Eastern Asia represents the biogeographic region with the highest species richness. We also assess the overlap of species across geographic regions and propose some hypotheses regarding the drivers of variability in species diversity and richness between different biogeographic regions.

Discovering the role of Patagonian birds in the dispersal of truffles and other mycorrhizal fungi

Dispersal is a key process that impacts population dynamics and structures biotic communities. Dispersal limitation influences the assembly of plant and microbial communities, including mycorrhizal fungi and their plant hosts. Mycorrhizal fungi play key ecological roles in forests by feeding nutrients to plants in exchange for sugars, so the dispersal of mycorrhizal fungi spores actively shapes plant communities. Although many fungi rely on wind for spore dispersal, some fungi have lost the ability to shoot their spores into the air and instead produce enclosed belowground fruiting bodies (truffles) that rely on animals for dispersal. The role of mammals in fungal spore dispersal is well documented, but the relevance of birds as dispersal agents of fungi has been understudied, despite the prominence of birds as seed dispersal vectors. Here, we use metagenomics and epifluorescence microscopy to demonstrate that two common, widespread, and endemic Patagonian birds, chucao tapaculos (Scelorchilus rubecula) and black-throated huet-huets (Pteroptochos tarnii), regularly consume mycorrhizal fungi and disperse viable spores via mycophagy. Our metagenomic analysis indicates that these birds routinely consume diverse mycorrhizal fungi, including many truffles, that are symbiotically associated with Nothofagaceae trees that dominate Patagonian forests. Epifluorescence microscopy of fecal samples confirmed that the birds dispersed copious viable spores from truffles and other mycorrhizal fungi. We show that fungi are a common food for both bird species and that this animal-fungi symbiosis is widespread and ecologically important in Patagonia. Our findings indicate that birds may also act as cryptic but critical fungal dispersal agents in other ecosystems.

Thaxterogaster revisited: A phylogenetic and taxonomic overview of sequestrate Cortinarius from Patagonia

In the Patagonian region, Cortinarius is the most diverse and abundant genus of ectomycorrhizal fungi with at least 250 species. Sequestrate forms were until recently documented within the genus Thaxterogaster, a genus now known to be polyphyletic, and many were consequently transferred to Cortinarius. Original descriptions were mostly available in German and Spanish and interpretations of morphological structures outdated. Despite recent advances in Cortinarius systematics, the current classification, diversity, and ecology of sequestrate "cortinarioid" fungi in Patagonia remain unclear. The objective of this study was to provide an update on sequestrate Cortinarius of southern South America. We documented each species with morphological descriptions, photographs, basidiospore scanning electron microscopy (SEM) images, and molecular characterization using nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (28S) sequence data. Original descriptions of taxa were also translated to English and revised based on fresh collections. We documented 24 species from Patagonia based on molecular data and conducted morphological and phylogenetic analysis for 18 previously described species based on type and reference specimens. In addition, we formally described two new species. Four additional taxa were provisionally determined as new but require further study. New ITS sequence data were produced from eight type specimens. We also provide a new name, Cortinarius gloiodes, nom. nov., for the taxon previously described as Thaxterogaster gliocyclus. In addition to the species treated in detail, we provided additional reference information and discussion on six described species that remained incompletely known or for which no recent collections were found. Of the 24 taxa documented from Patagonia, 15 species were assigned to 12 current sections in the genus Cortinarius. Analysis of spore ultrastructure showed that sequestrate forms of Patagonian Cortinarius lack a true perisporium.

Fungal Community Composition and Diversity Vary With Soil Horizons in a Subtropical Forest

Soil fungal communities, which drive many ecosystem processes, vary across soil horizons. However, how fungal communities are influenced by soil horizon layers remains largely unstudied. In this study, soil samples were collected from the organic horizon (O horizon) and mineral matter horizon (M horizon) in two sites of Dabie Mountain, China, and the effects of the two horizons on the soil fungal community composition were assessed based on Illumina MiSeq sequencing. Our results showed that soil fungal community composition varied with soil horizons, and soil fungal species richness and diversity in the O horizon were significantly higher than that in the M horizon. Total organic carbon (TOC), total organic nitrogen (TON), alkali-hydrolyzable nitrogen (AHN), available potassium (AK), and available phosphorus (AP) significantly influenced fungal community composition, abundance, and diversity across the two horizons (P < 0.05). Furthermore, precipitation was found to have a significant effect on fungal community composition. Our results demonstrate changes in fungal communities across soil horizons and highlight the importance of soil organic matter on fungal communities and diversity.

Phylogenetic relationships in the genus Podoserpula and description of P. aliweni, a new species from Chile

Phylogenetic analyses based on a three-locus nuclear data set (ITS1-5.8S-ITS2, the 5' end of the 28S, and the largest subunit of RNA polymerase I) supported the pagoda fungus (Podoserpula, Amylocorticiales) as a monophyletic group most closely related to species of Anomoporia, which is nonmonophyletic, and Amyloathelia. Phylogenetic relationships inferred from internal transcribed spacer (ITS) sequences of specimens sampled in Australia, Chile, China, Madagascar, and New Zealand divided Podoserpula into two major lineages: Clade A containing Australian and New Zealand collections designated P. pusio and the Chinese species P. ailaoshanensis, which have basidiospores with no reaction to Melzer's reagent, and Clade B, which includes a species described from Chile, P. aliweni, and specimens originating from Australia, Chile, Madagascar, and New Zealand with dextrinoid basidiospores. Podoserpula aliweni forms a unique branch in the phylogenetic tree and differs from its most closely related taxon by 1.8-2.1% in the ITS region. The new species exhibits a tree-like habit with a white to concolorous stipe-like base with the hymenophore's main subcylindrical axis bearing up to 18 superimposed pilei, slightly enrolled white margins shading from yellowish white to orange-yellow toward the center, and ellipsoid to broadly ellipsoid basidiospores measuring 4.0-4.5 × 3.5 µm. Ecologically, P. aliweni occurs during the rainy season, often gregariously on dried branches or wet soil under Nothofagus dombeyi or N. obliqua and has a distribution range of more than 600 km in southern Chile. This study extends the known distributional range and increases our knowledge on the phylogenetic diversity and taxonomy in Podoserpula.

Using aggregated field collection data and the novel r package fungarium to investigate fungal fire association

Understanding which fungi exhibit certain ecological traits, such as habitat, host, or substrate associations, and knowing how these traits change across space and time can provide invaluable insight into the roles fungi play in their respective ecosystems. Archived sporocarp data, such as the collection and observation records accessible through the Mycology Collections Portal (MyCoPortal), are well suited for trait investigations, since these records circumvent the need for field work, are geographically and temporally diverse, and often have detailed and trait-relevant environmental metadata. However, there are inefficiencies and inadequacies in the MyCoPortal online interface that affect data set generation and trait searching, and many of the available records have outdated or misspelled taxon names as well as misspelled location names. Thus, we created the r package fungarium, which enables the efficient download of complete MyCoPortal data sets from within the R environment, enhances the identification of trait-relevant records, confirms or updates taxon names while also accounting for spelling errors, and fixes misspelled location names. Utilizing this package and MyCoPortal data, we demonstrated methods for analyzing taxonomic, geographic, and temporal patterns in ecological traits, using fire association as an example. We found that fire association, which was quantified via fire-associated enrichment factors (fire-associated records/total records), differed substantially between taxa, and these differences were qualitatively supported by existing literature, as hypothesized. Sampling bias within the MyCoPortal data and limitations of the burned acreage data set used (i.e., Monitoring Trends in Burn Severity) were identified as confounding factors in our geographic and temporal analyses, as evidenced by the unexpected lack of correlation between fire association and burned acreage on county and year bases. However, both confounding factors likely depend on the trait analyzed and external data set used. Overall, the fungarium package and associated methods presented here effectively enable the use of archived sporocarp data for future ecological trait studies.

The Consequences of Our Changing Environment on Life Threatening and Debilitating Fungal Diseases in Humans

Human activities have significantly impacted the environment and are changing our climate in ways that will have major consequences for ourselves, and endanger animal, plant and microbial life on Earth. Rising global temperatures and pollution have been highlighted as potential drivers for increases in infectious diseases. Although infrequently highlighted, fungi are amongst the leading causes of infectious disease mortality, resulting in more than 1.5 million deaths every year. In this review we evaluate the evidence linking anthropomorphic impacts with changing epidemiology of fungal disease. We highlight how the geographic footprint of endemic mycosis has expanded, how populations susceptible to fungal infection and fungal allergy may increase and how climate change may select for pathogenic traits and indirectly contribute to the emergence of drug resistance.

Loose Ends in the Cortinarius Phylogeny: Five New Myxotelamonoid Species Indicate a High Diversity of These Ectomycorrhizal Fungi with South American Nothofagaceae

This paper is a contribution to the current knowledge of taxonomy, ecology and distribution of South American Cortinarius (Pers.) Gray. Cortinarius is among the most widely distributed and species-rich basidiomycete genera occurring with South American Nothofagaceae and species are found in many distinct habitats, including shrublands and forests. Due to their ectomycorrhizal role, Cortinarius species are critical for nutrient cycling in forests, especially at higher latitudes. Some species have also been reported as edible fungi with high nutritional quality. Our aim is to unravel the taxonomy of selected Cortinarius belonging to phlegmacioid and myxotelamonioid species based on morphological and molecular data. After widely sampling Cortinarius specimens in Patagonian Nothofagaceae forests and comparing them to reference collections (including holotypes), we propose five new species of Cortinarius in this work. Phylogenetic analyses of concatenated rDNA ITS-LSU and RPB1 sequences failed to place these new species into known Cortinarius sections or lineages. These findings highlight our knowledge gaps regarding the fungal diversity of South American Nothofagaceae forests. Due to the high diversity of endemic Patagonian taxa, it is clear that the South American Cortinarius diversity needs to be discovered and described in order to understand the evolutionary history of Cortinarius on a global scale.

Four new species of sequestrate Inocybe from Chilean Nothofagaceae forests

Sequestrate fungi have enclosed hypogeous, subhypogeous, or epigeous basidiomes and have lost the ability to actively discharge their spores. They can be distinguished as gasteroid (basidiome fully enclosed with a loculated hymenophore) or secotioid (basidiome with some agaricoid or pileate-stipitate features, but the lamellae are misshapen and unexposed or mostly unexposed at maturity). There are only four reports of sequestrate taxa within the ectomycorrhizal family Inocybaceae, three from Australia and one from western North America. Recent field work in Nothofagaceae forests in the Chilean coastal range revealed novel sequestrate forms of Inocybe. We examined specimens using a combination of morphological and molecular data from nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and portions of nuc 28S rDNA (28S) and the gene encoding the second largest subunit of RNA polymerase II (rpb2). Here, we describe four new sequestrate Inocybe species, I. ranunculiformis, I. anfractuosa, I. illariae, and I. nahuelbutensis. Results of our phylogenetic analysis resolved the four new species as distinct species-level clades with strong support, suggesting that these fungi have convergently evolved sequestrate forms independently. The species described here were all placed along with members of the "smooth-spored temperate austral clade," which includes almost exclusively Australasian and South American species of Inocybe.

Species Diversity With Comprehensive Annotations of Wood-Inhabiting Poroid and Corticioid Fungi in Uzbekistan

Uzbekistan, located in Central Asia, harbors high diversity of woody plants. Diversity of wood-inhabiting fungi in the country, however, remained poorly known. This study summarizes the wood-inhabiting basidiomycte fungi (poroid and corticoid fungi plus similar taxa such as Merismodes, Phellodon, and Sarcodon) (Agaricomycetes, Basidiomycota) that have been found in Uzbekistan from 1950 to 2020. This work is based on 790 fungal occurrence records: 185 from recently collected specimens, 101 from herbarium specimens made by earlier collectors, and 504 from literature-based records. All data were deposited as a species occurrence record dataset in the Global Biodiversity Information Facility and also summarized in the form of an annotated checklist in this paper. All 286 available specimens were morphologically examined. For 138 specimens, the 114 ITS and 85 LSU nrDNA sequences were newly sequenced and used for phylogenetic analysis. In total, we confirm the presence of 153 species of wood-inhabiting poroid and corticioid fungi in Uzbekistan, of which 31 species are reported for the first time in Uzbekistan, including 19 that are also new to Central Asia. These 153 fungal species inhabit 100 host species from 42 genera of 23 families. Polyporales and Hymenochaetales are the most recorded fungal orders and are most widely distributed around the study area. This study provides the first comprehensively updated and annotated the checklist of wood-inhabiting poroid and corticioid fungi in Uzbekistan. Such study should be expanded to other countries to further clarify species diversity of wood-inhabiting fungi around Central Asia.

A phylogenetic assessment of Pholiota and the new genus Pyrrhulomyces

Multigene data sets were assembled to evaluate the phylogeny of species attributed to the genus Pholiota sensu A.H. Sm. & Hesler. This effort included generation of just more than 200 new sequences from 19 type collections of Pholiota and recent samples from East Asia. Phylogenetic analyses reinforced the autonomous phylogenetic positions of pholiotoid taxa in the genera Flammula (Hymenogastraceae) and Kuehneromyces (Strophariaceae). Samples of Pholiota astragalina from diverse geographic regions split into two species-level lineages but occupied an isolated phylogenetic position apart from Pholiota sensu stricto. The new genus Pyrrhulomyces is described to accommodate P. astragalina and a new cryptic species from the Southern Appalachians, Pyrrhulomyces amariceps. Pyrrhulomyces is distinguished from other genera of Strophariaceae by the blackening basidiomata with a bitter taste, smooth basidiospores without a germ pore under light microscopy, presence of pleurochrysocystidia, an ixocutis, rugulose spore ornamentation under scanning electron microscope (SEM), and association with late stages of conifer wood decay. Pholiota subochracea was found to be sister to a clade containing samples of Hypholoma and Bogbodia, but this portion of the Strophariaceae will require further taxon and gene sampling to resolve relationships between these three taxa. Pholiota sensu stricto comprised at least two major groups, but several residual poorly placed lineages were also noted depending on the data set analyzed. New combinations are made in the genera Flammula, Kuehneromyces, and Stropharia for three species of Pholiota-P. abieticola, P. obscura, and P. scabella, respectively, based on molecular annotation of type collections. Overall, 20 new synonymies are proposed, mostly in Pholiota. Illustrations of Pyrrhulomyces are provided along with a key to genera of Strophariaceae and Hymenogastraceae.

Entoloma sequestratum, a new species from northern Thailand, and a worldwide key to sequestrate taxa of Entoloma (Entolomataceae)

Based on our study of the morphology and genetics of sporocarps collected in the mountains of northern Thailand, we herein describe Entoloma sequestratum as a new sequestrate member of the Entolomotaceae. This serves as the first report of a sequestrate member of the genus from Thailand. In addition, we provide a worldwide key to all of the described sequestrate members of the genus.

Marasmioid rhizomorphs in bird nests: Species diversity, functional specificity, and new species from the tropics

In tropical and subtropical rainforests, vegetative fungal rhizomorphs from the Marasmiineae are routinely used as construction material in bird nests. Because rhizomorphs seldom produce mushrooms within nests, the fungal species involved remain largely unknown. In turn, this limitation has prevented us from resolving broader questions such as whether specific fungal species are selected by birds for different functional roles (i.e., attachment, or parasite control). To fill some of these gaps, we collected 74 rhizomorph-containing bird nests from the Neo- and Afrotropics and used nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) sequences to discriminate between rhizomorph-forming species. In total we recovered 25 Marasmiineae species used by birds in nest construction, none of which were shared between the Neotropics and the Afrotropics. We also collected Marasmiineae basidiomes in the vicinity of nests and used ITS sequences to match these sporulating morphs with nest rhizomorphs for nine species. Basidiomes from an additional five species were found fruiting from rhizomorphs incorporated within bird nests. Finally, an additional six species were putatively identified based on publicly available sequence data. Rhizomorphs of five species were found to be utilized almost exclusively as lining material in nests. Lining material comes in direct contact with nestlings and is hypothesized to play a role in parasite control. Rhizomorphs from 10 species were used to attach and anchor nests to substrates; we matched six of those to fruiting litter trap-forming species collected in the understory. Litter traps hold large quantities of fallen litter material, suggesting that birds may preferentially use rhizomorphs that are adapted to bearing heavy loads for nest attachment. Finally, we describe two species of Marasmius-M. neocrinis-equi, sp. nov., and M. nidus-avis, sp. nov.-that are commonly found associated with bird nests and show that rhizomorph production is common across the genus.

Cones, needles and wood: Micraspis (Micraspidaceae, Micraspidales fam. et ord. nov.) speciation segregates by host plant tissues

Micraspis acicola was described more than 50 years ago to accommodate a phacidium-like fungus that caused a foliar disease of Picea mariana. After its publication, two more species were added, M. strobilina and M. tetraspora, all of them growing on Pinaceae in the Northern Hemisphere, but each species occupying a unique type of host tissue (needles, cones or wood). Micraspis is considered to be a member of class Leotiomycetes, but was originally placed in Phacidiaceae (Phacidiales), later transferred to Helotiaceae (Helotiales) and recently returned to Phacidiales but in a different family (Tympanidaceae). The genus remains poorly sampled, and hence poorly understood both taxonomically and ecologically. Here, we use morphology, cultures and sequences to provide insights into its systematic position in Leotiomycetes and its ecology. Our results show that the genus should not be included in Tympanidaceae or Phacidiaceae, and support the erection of a new family and order with a unique combination of morphological features supported by molecular data.

Fungi in aquatic ecosystems

Fungi are phylogenetically and functionally diverse ubiquitous components of almost all ecosystems on Earth, including aquatic environments stretching from high montane lakes down to the deep ocean. Aquatic ecosystems, however, remain frequently overlooked as fungal habitats, although fungi potentially hold important roles for organic matter cycling and food web dynamics. Recent methodological improvements have facilitated a greater appreciation of the importance of fungi in many aquatic systems, yet a conceptual framework is still missing. In this Review, we conceptualize the spatiotemporal dimensions, diversity, functions and organismic interactions of fungi in structuring aquatic food webs. We focus on currently unexplored fungal diversity, highlighting poorly understood ecosystems, including emerging artificial aquatic habitats.

Evidence for Co-evolutionary History of Early Diverging Lycopodiaceae Plants With Fungi

Lycopods are tracheophytes in the Kingdom Plantae and represent one of the oldest lineages of living vascular plants. Symbiotic interactions between these plants with fungi and bacteria, including fine root endophytes in Endogonales, have been hypothesized to have helped early diverging plant lineages colonize land. However, attempts to study the lycopod rhizobiome in its natural environment are still limited. In this study, we used Illumina amplicon sequencing to characterize fungal and bacterial diversity in nine Lycopodiaceae (club moss) species collected in New Zealand. This was done with generic fungal ITS rDNA primers, as well as Endogonales- and arbuscular mycorrhizal fungi (AMF)-selective primer sets targeting the 18S rDNA, and generic bacterial primers targeting the V4 region of the 16S rDNA. We found that the Lycopodiaceae rhizobiome was comprised of an unexpected high frequency of Basidiomycota and Ascomycota coincident with a low abundance of Endogonales and Glomerales. The distribution and abundance of Endogonales varied with host lycopod, and included a novel taxon as well as a single operational taxonomic unit (OTU) that was detected across all plant species. The Lycopodiaceae species with the greatest number and also most unique OTUs was Phlegmariurus varius, while the plant species that shared the most fungal OTUs were Lycopodiella fastigiatum and Lycopodium scariosum. The bacterial OTU distribution was generally not consistent with fungal OTU distribution. For example, community dissimilarity analysis revealed strong concordance between the evolutionary histories of host plants with the fungal community but not with the bacterial community, indicating that Lycopodiaceae have evolved specific relationships with their fungal symbionts. Notably, nearly 16% of the ITS rDNA fungal diversity detected in the Lycopodiaceae rhizobiome remained poorly classified, indicating there is much plant-associated fungal diversity left to describe in New Zealand.

Cortinarius section Thaumasti in South American Nothofagaceae forests

We studied the South American species of Cortinarius section Thaumasti based on morphological and molecular data. Members of this group can easily be identified in the field because the basidiomata are small and Phlegmacium-like with a bulbous stipe and the universal veil in most species forms a distinct volva at the base of the stipe. The phylogenetic delimitation of the clade was mostly in concordance with the earlier, morphology-based grouping of the South American taxa except that C. chrysophaeus was resolved outside of the clade. Altogether nine species were recognized in the section. Four species, C. chlorophanus, C. coleopus, C. cosmoxanthus, and C. vaginatus, were previously described by other authors, whereas three species, C. chlorosplendidus, C. olivaceovaginatus, and C. subcosmoxanthus, are described here as new. We were able to identify two remaining taxa, but we do not have sufficient morphological data to allow for a formal description. All of the species in C. section Thaumasti form ectomycorrhizal associations with Nothofagaceae. They have been documented from South America and New Zealand. The Patagonian species are considered endemic to the region. A key to the described species is provided.

Estimation of Fungal Diversity and Identification of Major Abiotic Drivers Influencing Fungal Richness and Communities in Northern Temperate and Boreal Quebec Forests

Fungi play important roles in forest ecosystems and understanding fungal diversity is crucial to address essential questions about species conservation and ecosystems management. Changes in fungal diversity can have severe impacts on ecosystem functionality. Unfortunately, little is known about fungal diversity in northern temperate and boreal forests, and we have yet to understand how abiotic variables shape fungal richness and composition. Our objectives were to make an overview of the fungal richness and the community composition in the region and identify their major abiotic drivers. We sampled 262 stands across the northern temperate and boreal Quebec forest located in the region of Abitibi-Témiscamingue, Mauricie, and Haute-Mauricie. At each site, we characterized fungal composition using Illumina sequencing, as well as several potential abiotic drivers (e.g., humus thickness, soil pH, vegetation cover, etc.). We tested effects of abiotic drivers on species richness using generalized linear models, while difference in fungal composition between stands was analyzed with permutational multivariate analysis of variance and beta-diversity partitioning analyses. Fungi from the order Agaricales, Helotiales, and Russulales were the most frequent and sites from the north of Abitibi-Témiscamingue showed the highest OTUs (Operational Taxonomic Unit) richness. Stand age and moss cover were the best predictors of fungal richness. On the other hand, the strongest drivers of fungal community structure were soil pH, average cumulative precipitation, and stand age, although much of community variance was left unexplained in our models. Overall, our regional metacommunity was characterized by high turnover rate, even when rare OTUs were removed. This may indicate strong environmental filtering by several unmeasured abiotic filters, or stronger than expected dispersal limitations in soil fungal communities. Our results show how difficult it can be to predict fungal community assembly even with high replication and efforts to include several biologically relevant explanatory variables.

Notes, outline and divergence times of Basidiomycota

The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406–430 Mya, classes are 211–383 Mya, and orders are 99–323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27–178 Mya, Pucciniomycotina from 85–222 Mya, and Ustilaginomycotina from 79–177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution.

Fungal functional ecology: bringing a trait-based approach to plant-associated fungi

Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro-organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function. Trait-based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and -omics-based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (Fun^Fun ). Fun^Fun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait-based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology.

Fungi of French Guiana gathered in a taxonomic, environmental and molecular dataset

In Amazonia, the knowledge about Fungi remains patchy and biased towards accessible sites. This is particularly the case in French Guiana where the existing collections have been confined to few coastal localities. Here, we aimed at filling the gaps of knowledge in undersampled areas of this region, particularly focusing on the Basidiomycota. From 2011, we comprehensively collected fruiting-bodies with a stratified and reproducible sampling scheme in 126 plots. Sites of sampling reflected the main forest habitats of French Guiana in terms of soil fertility and topography. The dataset of 5219 specimens gathers 245 genera belonging to 75 families, 642 specimens are barcoded. The dataset is not a checklist as only 27% of the specimens are identified at the species level but 96% are identified at the genus level. We found an extraordinary diversity distributed across forest habitats. The dataset is an unprecedented and original collection of Basidiomycota for the region, making specimens available for taxonomists and ecologists. The database is publicly available in the GBIF repository ( https://doi.org/10.15468/ymvlrp ).

A multigene phylogeny toward a new phylogenetic classification of Leotiomycetes

Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. These fungi are commonly detected in cultures from diseased tissue and from environmental DNA extracts. The identification of specimens from such character-poor samples increasingly relies on DNA sequencing. However, the current classification of Leotiomycetes is still largely based on morphologically defined taxa, especially at higher taxonomic levels. Consequently, the formal Leotiomycetes classification is frequently poorly congruent with the relationships suggested by DNA sequencing studies. Previous class-wide phylogenies of Leotiomycetes have been based on ribosomal DNA markers, with most of the published multi-gene studies being focussed on particular genera or families. In this paper we collate data available from specimens representing both sexual and asexual morphs from across the genetic breadth of the class, with a focus on generic type species, to present a phylogeny based on up to 15 concatenated genes across 279 specimens. Included in the dataset are genes that were extracted from 72 of the genomes available for the class, including 10 new genomes released with this study. To test the statistical support for the deepest branches in the phylogeny, an additional phylogeny based on 3156 genes from 51 selected genomes is also presented. To fill some of the taxonomic gaps in the 15-gene phylogeny, we further present an ITS gene tree, particularly targeting ex-type specimens of generic type species. A small number of novel taxa are proposed: Marthamycetales ord. nov., and Drepanopezizaceae and Mniaeciaceae fams. nov. The formal taxonomic changes are limited in part because of the ad hoc nature of taxon and specimen selection, based purely on the availability of data. The phylogeny constitutes a framework for enabling future taxonomically targeted studies using deliberate specimen selection. Such studies will ideally include designation of epitypes for the type species of those genera for which DNA is not able to be extracted from the original type specimen, and consideration of morphological characters whenever genetically defined clades are recognized as formal taxa within a classification.

Ectomycorrhizal fungi and soil enzymes exhibit contrasting patterns along elevation gradients in southern Patagonia

The biological and functional diversity of ectomycorrhizal (ECM) associations remain largely unknown in South America. In Patagonia, the ECM tree Nothofagus pumilio forms monospecific forests along mountain slopes without confounding effects of vegetation on plant-fungi interactions. To determine how fungal diversity and function are linked to elevation, we characterized fungal communities, edaphic variables, and eight extracellular enzyme activities along six elevation transects in Tierra del Fuego (Argentina and Chile). We also tested whether pairing ITS1 rDNA Illumina sequences generated taxonomic biases related to sequence length. Fungal community shifts across elevations were mediated primarily by soil pH with the most species-rich fungal families occurring mostly within a narrow pH range. By contrast, enzyme activities were minimally influenced by elevation but correlated with soil factors, especially total soil carbon. The activity of leucine aminopeptidase was positively correlated with ECM fungal richness and abundance, and acid phosphatase was correlated with nonECM fungal abundance. Several fungal lineages were undetected when using exclusively paired or unpaired forward ITS1 sequences, and these taxonomic biases need reconsideration for future studies. Our results suggest that soil fungi in N. pumilio forests are functionally similar across elevations and that these diverse communities help to maintain nutrient mobilization across the elevation gradient.

Unveiling new sequestrate Cortinarius species from northern Patagonian Nothofagaceae forests based on molecular and morphological data

Because of systematic sampling campaigns in the northern Patagonian Nothofagaceae forests of Argentina, several specimens of sequestrate fungi were collected. Some of those collections showed phylogenetic affinities and morphological similarities to members of the formerly recognized sequestrate genus Thaxterogaster, currently a synonym of Cortinarius on the basis of molecular data. Comparisons of macro- and micromorphological features and sequences of nuc rDNA internal transcribed spacer (ITS) regions have revealed that these collections belong to formerly undescribed species. The sequences of the four new taxa presented here, Cortinarius flavopurpureus, C. translucidus, C. nahuelhuapensis, and C. infrequens, were combined into a data set including additional sequences generated from herbarium collections and retrieved from public gene databases and analyzed by maximum likelihood and Bayesian inference methods. The four new species were resolved as distinct clades with strong support; at the same time, they showed unique morphological characteristics (hypogeous to subhypogeous habit, complete gasteromycetation, and spore shape and ornamentation) that separate them from previously described Cortinarius species. In addition, several undescribed and/or not previously sequenced species from these forests were detected through phylogenetic analysis of ectomycorrhizal root tip sequences. A key of characters to identify the sequestrate Cortinarius from Patagonia is provided.

Comparison of plant-soil feedback experimental approaches for testing soil biotic interactions among ecosystems

The study of interactions and feedbacks between plants and soils is a rapidly expanding research area, and a primary tool used in this field is to perform glasshouse experiments where soil biota are manipulated. Recently, there has been vigorous debate regarding the correctness of methods for carrying out these types of experiment, and specifically whether it is legitimate to mix soils from different sites or plots (mixed soil sampling, MSS) or not (independent soil sampling, ISS) to create either soil inoculum treatments or subjects. We performed the first empirical comparison of MSS vs ISS approaches by comparing growth of two boreal tree species (Picea abies and Pinus sylvestris) in soils originating from 10 sites near the boreal forest limit in northern Sweden, and 10 sites in the subarctic region where boreal forests may potentially expand as a result of climate change. We found no consistent differences in the conclusions that we reached whether we used MSS or ISS approaches. We propose that researchers should not choose a soil handling method based on arguments that one method is inherently more correct than the other, but rather that method choice should be based on correct alignment with specific research questions and goals.