The Indoor Mycobiomes of Daycare Centers Are Affected by Occupancy and Climate.

Many children spend considerable time in daycare centers and may be influenced by the indoor microorganisms there, including fungi. In this study, we investigate the indoor mycobiomes of 125 daycare centers distributed along strong environmental gradients throughout Norway. Dust samples were collected from doorframes outside and inside buildings using a community science sampling approach. Fungal communities in the dust samples were analyzed using DNA metabarcoding of the internal transcribed spacer 2 (ITS2) region. We observed a marked difference between the outdoor and indoor mycobiomes. The indoor mycobiomes included considerably more yeasts and molds than the outdoor samples, with Saccharomyces, Mucor, Malassezia, and Penicillium being among the most dominant fungal genera. Changes in the indoor fungal richness and composition correlated with numerous variables related to both outdoor and indoor conditions; there was a clear geographic structure in the indoor mycobiome composition that mirrored the outdoor climate, ranging from humid areas in western Norway to drier and colder areas in eastern Norway. Moreover, the number of children in the daycare centers, as well as various building features, influenced the indoor mycobiome composition. We conclude that the indoor mycobiomes in Norwegian daycare centers are structured by multiple factors and are dominated by yeasts and molds. This study exemplifies how community science sampling enables DNA-based analyses of a high number of samples covering wide geographic areas. IMPORTANCE With an alarming increase in chronic diseases like childhood asthma and allergies, there is an increased focus on the exposure of young children to indoor biological and chemical air pollutants. Our study of 125 daycares throughout Norway demonstrates that the indoor mycobiome not only reflects cooccurring outdoor fungi but also includes a high abundance of yeast and mold fungi with an affinity for indoor environments. A multitude of factors influence the indoor mycobiomes in daycares, including the building type, inhabitants, as well as the outdoor environment. Many of the detected yeasts and molds are likely associated with the human body, where some have been coupled with allergies and respiratory problems. Our results call for further studies investigating the potential impact of the identified daycare-associated mycobiomes on children's health.

Altitudinal upwards shifts in fungal fruiting in the Alps.

Many plant and animal species are changing their latitudinal and/or altitudinal distributions in response to climate change, but whether fungi show similar changes is largely unknown. Here, we use historical fungal fruit body records from the European Alps to assess altitudinal changes in fungal fruiting between 1960 and 2010. We observe that many fungal species are fruiting at significantly higher elevations in 2010 compared to 1960, and especially so among soil-dwelling fungi. Wood-decay fungi, being dependent on the presence of one or a few host trees, show a slower response. Species growing at higher elevations changed their altitudinal fruiting patterns significantly more than lowland species. Environmental changes in high altitudes may lead to proportionally stronger responses, since high-altitude species live closer to their physiological limit. These aboveground changes in fruiting patterns probably mirror corresponding shifts in belowground fungal communities, suggesting parallel shifts in important ecosystem functions.

Explaining European fungal fruiting phenology with climate variability.

Here we assess the impact of geographically dependent (latitude, longitude, and altitude) changes in bioclimatic (temperature, precipitation, and primary productivity) variability on fungal fruiting phenology across Europe. Two main nutritional guilds of fungi, saprotrophic and ectomycorrhizal, were further separated into spring and autumn fruiters. We used a path analysis to investigate how biogeographic patterns in fungal fruiting phenology coincided with seasonal changes in climate and primary production. Across central to northern Europe, mean fruiting varied by approximately 25 d, primarily with latitude. Altitude affected fruiting by up to 30 d, with spring delays and autumnal accelerations. Fruiting was as much explained by the effects of bioclimatic variability as by their large-scale spatial patterns. Temperature drove fruiting of autumnal ectomycorrhizal and saprotrophic groups as well as spring saprotrophic groups, while primary production and precipitation were major drivers for spring-fruiting ectomycorrhizal fungi. Species-specific phenology predictors were not stable, instead deviating from the overall mean. There is significant likelihood that further climatic change, especially in temperature, will impact fungal phenology patterns at large spatial scales. The ecological implications are diverse, potentially affecting food webs (asynchrony), nutrient cycling and the timing of nutrient availability in ecosystems.

Warming-induced shift in European mushroom fruiting phenology.

In terrestrial ecosystems, fungi are the major agents of decomposition processes and nutrient cycling and of plant nutrient uptake. Hence, they have a vital impact on ecosystem processes and the terrestrial carbon cycle. Changes in productivity and phenology of fungal fruit bodies can give clues to changes in fungal activity, but understanding these changes in relation to a changing climate is a pending challenge among ecologists. Here we report on phenological changes in fungal fruiting in Europe over the past four decades. Analyses of 746,297 dated and geo-referenced mushroom records of 486 autumnal fruiting species from Austria, Norway, Switzerland, and the United Kingdom revealed a widening of the annual fruiting season in all countries during the period 1970-2007. The mean annual day of fruiting has become later in all countries. However, the interspecific variation in phenological responses was high. Most species moved toward a later ending of their annual fruiting period, a trend that was particularly strong in the United Kingdom, which may reflect regional variation in climate change and its effects. Fruiting of both saprotrophic and mycorrhizal fungi now continues later in the year, but mycorrhizal fungi generally have a more compressed season than saprotrophs. This difference is probably due to the fruiting of mycorrhizal fungi partly depending on cues from the host plant. Extension of the European fungal fruiting season parallels an extended vegetation season in Europe. Changes in fruiting phenology imply changes in mycelia activity, with implications for ecosystem function.

Mycorrhizal fungal communities in coastal sand dunes and heaths investigated by pyrosequencing analyses.

Maritime sand dunes and coastal ericaceous heaths are unstable and dynamic habitats for mycorrhizal fungi. Creeping willow (Salix repens) is an important host plant in these habitats in parts of Europe. In this study, we wanted to assess which mycorrhizal fungi are associated with S. repens in four different coastal vegetation types in Southern Norway, three types from sand dunes and one from heaths. Moreover, we investigated which ecological factors are important for the fungal community structure in these vegetation types. Mycorrhizal fungi on S. repens root samples were identified by 454 pyrosequencing of tag-encoded internal transcribed spacer 1 (ITS1) amplicons. Significantly higher fungal richness was observed in hummock dunes and dune slacks compared to eroded dune vegetation. The compositional variation was mainly accounted for by location (plot) and vegetation type and was significantly correlated to content of carbon, nitrogen and phosphorus in soil. The investigated maritime sand dunes and coastal ericaceous heaths hosted mycorrhizal taxa mainly associated with Helotiales, Sebacinales, Thelephorales and Agaricales.

Arctic root-associated fungal community composition reflects environmental filtering.

There is growing evidence that root-associated fungi have important roles in Arctic ecosystems. Here, we assess the diversity of fungal communities associated with roots of the ectomycorrhizal perennial herb Bistorta vivipara on the Arctic archipelago of Svalbard and investigate whether spatial separation and bioclimatic variation are important structuring factors of fungal community composition. We sampled 160 plants of B. vivipara from 32 localities across Svalbard. DNA was extracted from entire root systems, and 454 pyrosequencing of ITS1 amplicons was used to profile the fungal communities. The fungal communities were predominantly composed of Basidiomycota (55% of reads) and Ascomycota (35%), with the orders Thelephorales (24%), Agaricales (13.8%), Pezizales (12.6%) and Sebacinales (11.3%) accounting for most of the reads. Plants from the same site or region had more similar fungal communities to one another than plants from other sites or regions, and sites clustered together along a weak latitudinal gradient. Furthermore, a decrease in per-plant OTU richness with increasing latitude was observed. However, no statistically significant spatial autocorrelation between sites was detected, suggesting that environmental filtering, not dispersal limitation, causes the observed patterns. Our analyses suggest that while latitudinal patterns in community composition and richness might reflect bioclimatic influences at global spatial scales, at the smaller spatial scale of the Svalbard archipelago, these changes more likely reflect varied bedrock composition and associated edaphic factors. The need for further studies focusing on identifying those specific bioclimatic and edaphic factors structuring root-associated fungal community composition at both global and local scales is emphasized.

Mushroom's spore size and time of fruiting are strongly related: is moisture important?

Most basidiomycete fungi produce annual short-lived sexual fruit bodies from which billions of microscopic spores are spread into the air during a short time period. However, little is known about the selective forces that have resulted in some species fruiting early and others later in the fruiting season. This study of relationships between morphological and ecological characteristics, climate factors and time of fruiting are based upon thorough statistical analyses of 66 520 mapped records from Norway, representing 271 species of autumnal fruiting mushroom species. We found a strong relationship between spore size and time of fruiting; on average, a doubling of spore size (volume) corresponded to 3 days earlier fruiting. Small-spored species dominate in the oceanic parts of Norway, whereas large-spored species are typical of more continental parts. In separate analyses, significant relationships were observed between spore size and climate factors. We hypothesize that these relationships are owing to water balance optimization, driven by water storage in spores as a critical factor for successful germination of primary mycelia in the drier micro-environments found earlier in the fruiting season and/or in continental climates.

Mushroom fruiting and climate change.

Many species of fungi produce ephemeral autumnal fruiting bodies to spread and multiply. Despite their attraction for mushroom pickers and their economic importance, little is known about the phenology of fruiting bodies. Using approximately 34,500 dated herbarium records we analyzed changes in the autumnal fruiting date of mushrooms in Norway over the period 1940-2006. We show that the time of fruiting has changed considerably over this time period, with an average delay in fruiting since 1980 of 12.9 days. The changes differ strongly between species and groups of species. Early-fruiting species have experienced a stronger delay than late fruiters, resulting in a more compressed fruiting season. There is also a geographic trend of earlier fruiting in the northern and more continental parts of Norway than in more southern and oceanic parts. Incorporating monthly precipitation and temperature variables into the analyses provides indications that increasing temperatures during autumn and winter months bring about significant delay of fruiting both in the same year and in the subsequent year. The recent changes in autumnal mushroom phenology coincide with the extension of the growing season caused by global climate change and are likely to continue under the current climate change scenario.

High diversity of root associated fungi in both alpine and arctic Dryas octopetala.

BACKGROUND: Dryas octopetala is a widespread dwarf shrub in alpine and arctic regions that forms ectomycorrhizal (ECM) symbiotic relationships with fungi. In this study we investigated the fungal communities associated with roots of D. octopetala in alpine sites in Norway and in the High Arctic on Svalbard, where we aimed to reveal whether the fungal diversity and species composition varied across the Alpine and Arctic regions. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was used to identify the fungal communities from bulk root samples obtained from 24 plants. RESULTS: A total of 137 operational taxonomic units (OTUs) were detected (using 97% similarity cut off during sequence clustering) and well-known ECM genera such as Cenococcum, Cortinarius, Hebeloma, Inocybe and Tomentella occurred frequently. There was no decrease in fungal diversity with increasing latitude. The overall spatial heterogeneity was high, but a weak geographical structuring of the composition of OTUs in the root systems was observed. Calculated species accumulation curves did not level off. CONCLUSIONS: This study indicates that the diversity of fungi associated with D. octopetala does not decrease in high latitude arctic regions, which contrasts observations made in a wide spectrum of other organism groups. A high degree of patchiness was observed across root systems, but the fungal communities were nevertheless weakly spatially structured. Non-asymptotical species accumulation curves and the occurrence of a high number of singletons indicated that only a small fraction of the fungal diversity was detected.

Open-source data reveal how collections-based fungal diversity is sensitive to global change.

PREMISE OF THE STUDY: Fungal diversity (richness) trends at large scales are in urgent need of investigation, especially through novel situations that combine long-term observational with environmental and remotely sensed open-source data. METHODS: We modeled fungal richness, with collections-based records of saprotrophic (decaying) and ectomycorrhizal (plant mutualistic) fungi, using an array of environmental variables across geographical gradients from northern to central Europe. Temporal differences in covariables granted insight into the impacts of the shorter- versus longer-term environment on fungal richness. RESULTS: Fungal richness varied significantly across different land-use types, with highest richness in forests and lowest in urban areas. Latitudinal trends supported a unimodal pattern in diversity across Europe. Temperature, both annual mean and range, was positively correlated with richness, indicating the importance of seasonality in increasing richness amounts. Precipitation seasonality notably affected saprotrophic fungal diversity (a unimodal relationship), as did daily precipitation of the collection day (negatively correlated). Ectomycorrhizal fungal richness differed from that of saprotrophs by being positively associated with tree species richness. DISCUSSION: Our results demonstrate that fungal richness is strongly correlated with land use and climate conditions, especially concerning seasonality, and that ongoing global change processes will affect fungal richness patterns at large scales.

European mushroom assemblages are darker in cold climates.

Thermal melanism theory states that dark-colored ectotherm organisms are at an advantage at low temperature due to increased warming. This theory is generally supported for ectotherm animals, however, the function of colors in the fungal kingdom is largely unknown. Here, we test whether the color lightness of mushroom assemblages is related to climate using a dataset of 3.2 million observations of 3,054 species across Europe. Consistent with the thermal melanism theory, mushroom assemblages are significantly darker in areas with cold climates. We further show differences in color phenotype between fungal lifestyles and a lifestyle differentiated response to seasonality. These results indicate a more complex ecological role of mushroom colors and suggest functions beyond thermal adaption. Because fungi play a crucial role in terrestrial carbon and nutrient cycles, understanding the links between the thermal environment, functional coloration and species' geographical distributions will be critical in predicting ecosystem responses to global warming.

The real nature of the indole alkaloids in Cortinarius infractus: evaluation of artifact formation through solvent extraction method development.

This study was triggered by the absence of infractine in EtOH extracts of Cortinarius infractus and the presence of the beta-carboline-1-propionic acid [I. Brondz, K. Høiland, D.S. Bell, A.R. Annino, TheReporter, Supelco 24 (3) (2006) 6]. In previous studies it was determined that C. infractus contained indole alkaloid substances of the infractine group [W. Steglich, L. Kopanski, M. Wolf, M. Moser, G. Tegtmeyer, Indolalkaloide aus dem Blaetterpilz Cortinarius infractus (Agaricales). Tetrahedron Lett. 25 (1984) 2341]. It is quite possible that some of these compounds do not exist in any other mushroom species and therefore they could prove to be valuable chemotaxonomic markers. Proper classification of this species requires that the chemical markers are identified correctly. In this study, the presence of several compounds previously found in C. infractus (Pers.: Fr.) Fr. is questioned. In this investigation, it was shown by HPLC-MS that infractine and 6-hydroxyinfractine, previously described as constituents of C. infractus, were artifacts produced during the extraction process. Also, the molecular species that participate in the artefact formation were identified. Infractine and 6-hydroxyinfractine, reported earlier in C. infractus, originate from the precursor (pre-infractine) beta-carboline-1-propionic acid during extraction with methanol.

Links between Genetic Groups, Indole Alkaloid Profiles and Ecology within the Grass-Parasitic Claviceps purpurea Species Complex.

The grass parasitic fungus Claviceps purpurea sensu lato produces sclerotia with toxic indole alkaloids. It constitutes several genetic groups with divergent habitat preferences that recently were delimited into separate proposed species. We aimed to 1) analyze genetic variation of C. purpurea sensu lato in Norway, 2) characterize the associated indole alkaloid profiles, and 3) explore relationships between genetics, alkaloid chemistry and ecology. Approximately 600 sclerotia from 14 different grass species were subjected to various analyses including DNA sequencing and HPLC-MS. Molecular results, supported by chemical and ecological data, revealed one new genetic group (G4) in addition to two of the three known; G1 (C. purpurea sensu stricto) and G2 (C. humidiphila). G3 (C. spartinae) was not found. G4, which was apparently con-specific with the recently described C. arundinis sp. nov, was predominantly found in very wet habitats on Molinia caerulea and infrequently in saline habitats on Leymus arenarius. Its indole-diterpene profile resembled G2, while its ergot alkaloid profile differed from G2 in high amounts of ergosedmam. In contrast to G1, indole-diterpenes were consistently present in G2 and G4. Our study supports and complements the newly proposed species delimitation of the C. purpurea complex, but challenges some species characteristics including host spectrum, habitat preferences and sclerotial floating ability.

Multivariate analysis of fatty acids in spores of higher basidiomycetes: a new method for chemotaxonomical classification of fungi.

The aim of the present work was to study the possibility of using the fatty acid content in the basidiospores as a taxonomic tool. Basidiospores of Armillaria borealis, Amanita muscaria, Agaricus sylvicola, Hypholoma capnoides, Cortinarius nemorensis and Russula delica were used. The content of fatty acids as well as other substances may vary to a certain degree depending on the part (pileus, stipe, lamella) or stage of development of the actual basidiocarp analysed. Moreover, substances from fungivorous invertebrates, parasitic fungi or bacteria may be found in the chemical analyses of the basidiocarps. Chemotaxonomic conclusions may, therefore, be burdened with serious uncertainties. On the other hand, the ripe basidiospores are terminated structures and belong to the most homogenous structures encountered from a basidiocarp. Their shape, size, colour and ornamentation are considerably homogenous within an actual species. Therefore, the basidiospores are often used as a reliable differentiating characteristic separating species as well as taxa of higher categories. From a practical point of view, ripe spores are easy to obtain in relatively large quantities with simple techniques, and they are not so prone to decay as the carpophore tissue. In the present study, gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), after methanolysis of the fungus spores, were used to map essential fatty acids in basidiomycetes. Gas chromatography and gas chromatography-mass spectrometry revealed the presence of fatty acids of C12:0-C24:0 size in the basidiospores of these higher basidiomycetes. The major fatty acid in H. capnoides is C18:2, and the major fatty acid in the other species is C18:1. The basidiospores proved to be a good source of fatty acids for chemotaxonomic investigations of agarics.

Population genetics and spatial structure of the fairy ring fungus Marasmius oreades in a Norwegian sand dune ecosystem.

The population genetics and spatial structure of the fairy ring fungus Marasmius oreades (Bolt. : Fr.) Fr. was studied by DNA amplification fingerprinting (DAF). Basidiocarp samples were collected from fairy rings from two separate sand dune systems of about 560 m(2) and 1750 m(2), respectively, on the Lista Peninsula in southwestern Norway in 1996. Samples were collected after a careful mapping of fairy rings and a vegetation survey of the composition and spatial structure of vascular plants, bryophytes and lichens. DAF with standard arbitrary oligonucleotide primers was used to examine the genetic relationship between basidiocarp samples. The study showed that the fungal population contained a high number of genotypes and that about 90% of the fairy rings represented a separate genet. Both cluster and phylogenetic analyses of DAF amplification products established relationships between fairy rings and showed that genetically similar basidiocarps were found close to each other. Overall results showed a weak correspondence between genotype and spatial distribution and no correspondence between genotype and composition of the surrounding vegetation. Furthermore, the occurrence of the four dominant sand dune grass species was randomly distributed among the localities housing the various fungal genotypes, indicating that the fungus did not exhibit genotypic specialization to the various grass species that could host it as a pathogen. Results show that establishment of new individuals generally was mediated by basidiospore dispersal and not by fragmenting dikaryotic, vegetative mycelium, as previously proposed.

The presence of orellanine in spores and basidiocarp from Cortinarius orellanus and Cortinarius rubellus.

This is the first report quantifying the orellanine content in basidiospores. The toxin content and tissue distribution of orellanine were determined from Cortinarius orellanus (Fr.) Fr. and Cortinarius rubellus Cooke. Basidiospores, the basidiocarp, divided into cap and stem, and mycorrhiza roots were analyzed to determine the amount of orellanine by reversed phase high performance liquid chromatography and thin layer chromatography. The orellanine contents in spores were 0.31% (C. orellanus) and 0.09% (C. rubellus). In caps, we found the toxin content to be 0.94% (C. orellanus) and 0.78% (C. rubellus), in stems 0.48% (C. orellanus) and 0.42% (C. rubellus) and in mycorrhiza roots from C. rubellus we determined the orellanine contents to 0.03%. In addition, extracts from the different structures of the basidiocarp of C. orellanus and C. rubellus, with an orellanine content corresponding to 25 nmol, inhibited the growth of Bacillus subtilis.

Molecular characterization and evaluation of plant litter-associated fungi from the spring 'grazing corridor' of a sheep herd vulnerable to alveld disease.

This study sample and identify species of fungi on withered vegetation in the spring 'grazing corridor' from infields to Narthecium bogs for a sheep herd almost chronically vulnerable to phototoxic disease. Hepatogen photosensitizing disorders like alveld attack grazing sheep, especially lambs, in various parts of the world. It has been hypothesized that saponin metabolites in the monocotyledonous plant Narthecium ossifragum causes the disorder in Norway, however, this has not been verified. Thus, the search for other causal agents or saponin cofactors (the cofactor hypothesis) has been intensified, and endophytic poisonous fungi associated with dead N. ossifragum leaves and grasses are among the prime suspects. The fungal diversity was targeted by obtaining axenic cultures from surface-sterilized plant material, with subsequent DNA isolation, PCR, and sequencing of the ITS nrDNA region. The taxonomic affinities of the obtained sequences were thereafter explored by similarity searches against the public access sequence database EMBL/GenBank/DDBJ. Among the spectrum of identified taxa were representatives of Cladosporium, Fusarium, Penicillium, and Trichoderma, all of which are well known as potential producers of toxins. A possible involvement of these toxic species in the etiology of alveld is evaluated and discussed.

UNITE: a database providing web-based methods for the molecular identification of ectomycorrhizal fungi.

Identification of ectomycorrhizal (ECM) fungi is often achieved through comparisons of ribosomal DNA internal transcribed spacer (ITS) sequences with accessioned sequences deposited in public databases. A major problem encountered is that annotation of the sequences in these databases is not always complete or trustworthy. In order to overcome this deficiency, we report on UNITE, an open-access database. UNITE comprises well annotated fungal ITS sequences from well defined herbarium specimens that include full herbarium reference identification data, collector/source and ecological data. At present UNITE contains 758 ITS sequences from 455 species and 67 genera of ECM fungi. UNITE can be searched by taxon name, via sequence similarity using blastn, and via phylogenetic sequence identification using galaxie. Following implementation, galaxie performs a phylogenetic analysis of the query sequence after alignment either to pre-existing generic alignments, or to matches retrieved from a blast search on the UNITE data. It should be noted that the current version of UNITE is dedicated to the reliable identification of ECM fungi. The UNITE database is accessible through the URL http://unite.zbi.ee