Ascension Island is a remote oceanic island that was a volcanic desert prior to human colonisation. In the 19th century, an artificial cloud forest was established by a military garrison to improve the scarce water supply. Using ITS metabarcoding of topsoil environmental DNA, we compared the fungal communities of the desert and the Green Mountain cloud forest. Forest soils had higher total nitrogen and carbon, and lower pH than desert soils. Fungal richness was higher in forest soils and ordination analysis revealed distinct fungal communities in each habitat. Both habitats contained a high percentage of unclassified fungal OTUs, implying the presence of native/endemic fungal flora, with a shift from Ascomycota in the desert to Asco-Basidiomycota in the forest. Indicator species analysis revealed habitat- and vegetation-specific fungal taxa, and the presence of cosmopolitan fungi in forest and unknown fungi in the desert soils, suggesting reshaping of fungal communities due to the afforestation.
The fungal mycelium is a dynamic structure capable of complex spatial responses, yet its spatial responses to anthropogenic stressors are rarely tackled, despite the often-heterogeneous distribution of stressors. In this study, 23 saprotrophic fungal isolates were exposed to a localized copper source, and spatial mycelial responses were assessed through qualitative morphological scoring and compared with conventional biomass and mycelial extension metrics. This approach revealed diverse intra- and interspecific morphological responses. Most fungi showed asymmetric inhibition near the copper while maintaining growth elsewhere, indicating spatial containment. Three inhibition front morphologies, concave, convex, and straight, suggest different underlying mechanisms, including hyphal tip inhibition and structural growth constraints. Barrage-like formations, even in early-diverging Mucoromycota, point to conserved spatial defense strategies. Other responses included vertical growth redirection, global suppression without local inhibition, and reproductive shifts. These findings emphasize a need for spatially explicit approaches for predicting effects of environmental pollution on fungal biodiversity.
Extinction risk assessment of the world's funga lags far behind that of flora and fauna, impeding inclusion in conservation policy and action. Prediction and automation have helped accelerate Red Listing of plants, facilitating prioritization of taxa for assessment and reducing the manual input required. Similar approaches for fungi could help address their extreme underrepresentation on the Red List. We used Bayesian logistic regression modelling and an automated assessment pipeline to identify and rapidly assess 715 species of North American macrofungi confidently predicted to be Least Concern. However, fundamental data are lacking for risk prediction for many fungi: only one in twenty species analysed could be classified as confidently Least Concern. Our workflow could facilitate increased coverage of fungi on the Red List. Nonetheless, continued investment in assessing potentially threatened fungi is essential for improving the accuracy of future predictions and, more importantly, for guiding conservation action for species at risk.
Phyllosphere fungal community assembly in agroecosystems includes biotic filtering by crop hosts. However, it is uncertain whether there are plant traits common across multiple crops that could serve as an additional biotic filter or be used as predictive tools to design more optimal mycobiome compositions. Here, we leveraged a large, multi-location field experiment on corn, switchgrass, and wheat in North Carolina, USA to determine if foliar fungi respond to plant traits in a crop-dependent or -independent manner. We found that crop performance traits strongly linked to yield (Height, Leaf Area Index) dominated predictions for both fungal community turnover and joint species distributions, with rapid fungal shifts across smaller to larger plants. However, predictions for fungal response to plant traits were consistently improved by including crop identity. Based on our results, foliar fungal community assembly depends on both the plant host and associated plant traits.
Metabarcoding of environmental DNA is widely used to assess fungal diversity, yet the choice of bioinformatic pipeline strongly influences results. Here we compare five pipelines to detect Cladonia diversity from soil eDNA across Europe, using an extensive floristic survey combined with Sanger sequencing as a reference. All pipelines similarly detected dominant species but differed in their recovery of rare taxa, hidden diversity, or putative artefacts. The total number of operational taxonomic units (OTUs) varied 2.5-fold across pipelines, and overlap with the reference dataset ranged from 21% to 40%. The pipeline by Bálint et al. (2014), followed by Swarm v2 clustering and VSEARCH chimera filtering, achieved the greatest agreement with the taxonomic survey and recovered the highest number of rare OTUs. The DADA2-based pipeline with DECIPHER clustering yielded the highest number of OTUs not found by the taxonomic survey. In contrast, LULU curation yielded the most conservative dataset, with the lowest diversity and lowest overlap with the Sanger-verified reference.
Field-based information on the relationship between desert truffle elemental composition and extractable soil element pools remains scarce in semi-arid calcareous ecosystems. This study examined five natural T. boudieri habitats associated with Helianthemum salicifolium in Central Anatolia (Kirsehir, Türkiye). Each habitat was treated as the ecological unit of analysis, with pooled ascocarp samples and composite soil samples used to describe habitat-level fungal and edaphic elemental profiles. Soils were slightly alkaline (pH 7.52–7.68), low in salinity (EC 0.20–0.58 mS cm−1), and extremely poor in extractable P (0.00205–0.02355 g kg−1). Ascocarp elemental composition varied among habitats. K was the dominant macroelement (19.5–27.7 g kg−1), P ranged from 7.0 to 10.3 g kg−1, and Fe showed the widest microelement range (194–913 mg kg−1). Ascocarp-to-extractable soil ratios were calculated to describe element-specific divergence between ascocarps and operationally accessible soil pools and log10-transformed ratios were used for exploratory testing of divergence from parity. Across habitats, ascocarps maintained relatively high P concentrations despite extremely low extractable soil P, whereas Ca showed consistently low ratios relative to extractable soil Ca. Fe variability suggested stronger habitat- or microsite-level heterogeneity. These patterns indicate that T. boudieri ascocarp elemental composition does not simply mirror the extractable soil pool under calcareous dryland conditions. Rather than confirming specific uptake mechanisms, this habitat-level dataset identifies testable ecological hypotheses concerning P maintenance, Ca constraint, Fe microsite variability, and the T. boudieri–H. salicifolium–soil interface.
Citizen science is an increasingly important tool for biodiversity and conservation studies. We developed a small-scale, local Citizen Science Program (CSP) to address the lack of fungal inventorying and monitoring in poorly studied montane environments of Southern Brazil and to assess whether non-specialist volunteers could complement records from researchers. Thirty-two local volunteers were trained to use a mobile phone app, generating 264 macrofungal records over 14 months. Comparing volunteer and researcher collections from the same area and period showed 37 shared genera, 54 recorded only by researchers, and 28 only by volunteers, indicating that volunteers generated 23% of unique genus records. The programme also helped document 18 wild edible mushroom species (three of them recorded only by volunteers and 10 recorded only by researchers) and monitor three threatened fungal species. These findings underscore the complementary roles of researchers and non-specialist volunteers and show that small-scale local citizen science initiatives can help inventory and monitor fungal diversity while filling knowledge gaps in understudied regions.
Ectomycorrhizal fungi (EMF) are essential for forest health. In urban reserves, environmental stressors can affect both their plant hosts and the small mammals that disperse their propagules. We aimed to assess the response of EMF to urbanisation by comparing the diversity (i.e., Shannon diversity and richness) and composition of EMF communities in small mammal scats and soils from urban reserves to those in native forest sites in Sydney, Australia. We also tested the effects of season and small mammal species on EMF community diversity and composition in small mammal scats. Using ITS1 barcoding, we found that soils supported more diverse and distinct EMF communities than scats. EMF diversity was similar in urban reserves and native forest sites in both soils and scats, but community composition differed between the habitat types. In scats, EMF Shannon diversity was higher in autumn than in spring, while richness did not differ between seasons. Our comparison of the two most frequently captured mammals, Brown antechinus (Antechinus stuartii) and the Australian bush rat (Rattus fuscipes), revealed that antechinus scats had higher EMF Shannon diversity, but similar richness, than those of bush rats. EMF community composition was also different between these two small mammal species. Overall, our results indicate that urban reserves can act as important refugia for EMF, and that small mammals in these reserves may disperse a diverse pool of EMF.
Fungal communities inhabiting the wood of living trees influence host vitality and wood quality yet remain poorly characterized for many economically important tree species. In this study, the mycobiomes of heartwood and sapwood in three Populus lineages (P. tremula, P. tremula x tremuloides and species and hybrids in Populus sect. Tacamahaca) were characterized using ITS2 metabarcoding. We observed clear, differences between wood types, with heartwood mycobiomes being less diverse than sapwood communities. Heartwood samples were enriched in fungi belonging to class Leotiomycetes, particularly the genera Ascocoryne, Cadophora and Neobulgaria, which have potential impacts on wood quality (discoloration and decay). Beta diversity analyses revealed that wood type was the primary driver of community composition. These findings provide insights into the spatial organization of fungal communities within wood from living Populus trees and highlight the need for mechanistic studies of heartwood mycobiome assembly and its implications for wood quality in plantation forestry.
Fungal endophytes affect plants in ways ranging from beneficial to detrimental depending on soil nutrient availability, yet the role of endophyte community composition in shaping these outcomes remains unclear. We tested how nitrogen form (NH4+ versus NO3) and dose shape fungal communities in leaves and roots of Spartina alterniflora in a salt marsh ecosystem. Using culture-based isolation and in vitro assays of hyphal growth and biomass, we asked whether field nitrogen enrichment altered fungal communities and whether resulting shifts produced legacy effects on fungal traits. Leaf endophyte richness was higher than root richness but did not change with enrichment. In contrast, root richness shifted under NH4+ enrichment, while NO3- enrichment had no effect. Trait assays showed that fungi from NH4+ enriched field plots grew poorly under NH4+ lab nutrient resource conditions, whereas fungi from NO3- enriched field plots maintained high growth across lab nutrient treatments. These results suggest nitrogen addition leaves legacy effects in the mycobiome.
The spread of Hymenoscyphus fraxineus and the ash dieback epidemic threatens the biodiversity associated with European ash (Fraxinus excelsior). Following a loss of ash from the landscape, sycamore (Acer pseudoplatanus) and beech (Fagus sylvatica), are expected to dominate replacement by natural colonisation. Here we analyse fruit body records using a null modelling framework to examine the macro-fungal diversity associated with ash within the UK and Ireland. In total, 55 species were significantly associated with ash, 22 of which exhibited a high level of dependency on F. excelsior substrates. Records of saproxylic fungi pertaining to ash were compared with those of the two dominant replacement species. There were large ecological distances between the ash community and the communities recorded on the alternative hosts, indicating that both beech and sycamore are likely to function poorly as compensatory analogues for ash in terms of the saprotrophic fungal communities they support.
Fungi often exhibit specific associations with particular substrates in forest ecosystems. However, how the fungal species pool, environmental filtering, and dispersal jointly shape fungal distributions across multiple forest substrates remains poorly understood. To fill this gap, we analysed fungal species composition and identified indicator species across 11 forest substrates, including leaves, leaf litter, mammal faeces, topsoil, subsoil, mosses, lichens, bark, snow, dead wood, and decaying fungal fruiting bodies. Over 70% of 2772 species occurred in fewer than three substrates, 63% were substrate-specific, and indicator proportions and strengths varied among substrates. Species composition in faeces, wood, and subsoil was the most distinct, whereas leaves, mosses, and snow exhibited the highest fungal community similarity. Phylogenetic clustering was significant in most substrates except subsoil, topsoil, and wood. Among all substrates, leaves, snow, moss, and topsoil shared the highest numbers of indicator species with other substrates, suggesting strong linkages among these substrates. Overall, the observed patterns are consistent with environmental filtering and dispersal, and they suggest that substrates differ in their roles as propagule sources and reservoirs.
Gaeumannomyces species (Magnaporthales, Ascomycota) occur worldwide as both pathogenic and commensal root-associates of cereal crops and wild grasses, meaning these fungi have considerable impacts on both arable and pastoral food security. However, as these fungi are obscured below-ground and difficult to work with, our understanding of Gaeumannomyces lags far behind that of many other plant-associated fungi lineages. This study has made use of the GlobalFungi database to address a fundamental question: what is the geographical distribution of Gaeumannomyces species? To align with up-to-date taxonomy, classification has been refined using evolutionary placement of sequences to a reference tree. This is complemented with a synthesis of host and lifestyle reports to survey the range exhibited across the genus and assess knowledge gaps. The resulting overview consolidates current knowledge to highlight the potential role of wild reservoirs in crop disease dynamics and identifies G. australiensis as a potential emergent pathogen in China.
Wrightoporia araucariae is a Critically Endangered polypore that grows exclusively on dead trunks of Araucaria angustifolia. Since its original description in 2014, no additional records have been reported. To support its conservation and refine knowledge of its distribution, field surveys, fungarium revisions, and habitat-suitability modeling were conducted. After 25 expeditions across 17 localities throughout south Brazil, no new specimens were found. Fungarium revisions confirmed an additional collection from Canela, Rio Grande do Sul, while a previous record from Santa Catarina was reidentified as Antrodia sp., restricting its occurrence to Rio Grande do Sul. Ensemble models based on the Area of Habitat approach indicated that although the climatically suitable area is broad, only 7.4% overlaps with Araucaria forest fragments. Projections for 2070 show losses of approximately 80-97%, with remaining areas limited to isolated high-altitude refugia. Areas with high probability of occurrence and low uncertainty and extrapolation identified in future climate projections should guide in-situ conservation actions to safeguard refugia for W. araucariae. These results support the reassessment of W. araucariae as Critically Endangered under IUCN subcriteria A3c and C2a(ii).
Foliar fungal endophytes shape plant health and stress responses, yet their dynamics across co-occurring oak species remain poorly resolved. Using ITS metabarcoding, we surveyed endophyte communities in blue oaks (Quercus douglasii) and interior live oaks (Quercus wislizeni) across two microhabitats and three seasonal time points. Interior live oaks hosted more diverse and compositionally distinct fungal communities than blue oaks. Seasonal turnover was pronounced, with saprotrophs increasing and plant pathogens declining by late summer, particularly in blue oaks. Ridge-site trees harbored slightly less diverse communities than valley-site trees, highlighting microclimate effects. Blue oaks, especially those at exposed ridge sites, supported higher pathogen loads potentially contributing to regional blue oak decline. These findings reveal that foliar fungal communities vary by host species, season, and site, with blue oaks harboring higher pathogen loads that may have implications for understanding regional blue oak decline.
Root-associated fungi can influence plant germination, growth, survival, reproduction and coexistence. Yet, their diversity and distribution are still poorly known with most studies focusing on single plant species. We studied the diversity, composition and biogeographic patterns of root-associated fungi from small islands of five archipelagos, spanning diverse climates, plant communities and island characteristics. Our results revealed a distinct biogeographic pattern, with minimal taxon overlap and different diversity levels linked to island age, climate, and plant diversity. Ascomycetes dominated all sites, but basidiomycete abundance peaked on tropical islands. Saprotrophs and pathogens were the most abundant functional groups across islands. In contrast, mutualistic fungi showed disproportionately high diversity relative to their low abundance, reaching maximum values on tropical Fregate and temperate Na Redona. Our data also confirm the worldwide distribution of some wind-dispersed ascomycete genera with broad ecological niches, while uncovering unexpected hotspots of wild reservoirs for key plant pathogens.
The influence of Leptographium terebrantis stem infection on constitutive and induced oleoresin and soluble phenolics in terminal shoots was assessed in a Pinus taeda plantation using three inoculum densities. The pathogen causes wilt disease by invading and colonizing root xylem tissues. We observed three levels of P. taeda defense in response to L. terebrantis during a two-year period interrupted by drought. Normal carbon allocation to growth was maintained and constitutive oleoresin production was observed at low and medium inoculum densities, with oleoresin induction observed among the medium inoculum density trees. At the high inoculum level, oleoresin flow occurred at a level similar to the medium inoculum density trees and carbon allocation to growth was diminished. Terminal shoot phenolic concentration was unaffected by the pathogen. Our findings validate the view that simultaneous occurrence of wilt disease and drought reduces constitutive and induced defenses by interfering with carbon fixation and allocation to growth.
