As part of an ongoing study of marine fungi associated with seagrasses, we discovered a novel root-fungus symbiosis in the Indo-Pacific species Thalassodendronciliatum from Mauritius. Culturing its mycobionts yielded dozens of morphologically and genetically uniform isolates, all representing a previously unknown fungus. A second undescribed fungus was isolated from saline soils in Czechia. Phylogenetic analyses based on three rDNA markers confirmed both taxa as distinct, hitherto unknown lineages within the Lulworthiales, which are introduced here as Thalassodendromycespurpureus gen. et sp. nov. and Halomyrmapluriseptata gen. et sp. nov., respectively. Both species developed characteristic structures under culture conditions that enabled their morphological characterisation: T.purpureus forms distinctive clusters of dark brown monilioid hyphae, while H.pluriseptata is characterised by holoblastic conidiogenesis and solitary, dark brown, multicellular conidia. Thalassodendromyces clustered in a strongly supported clade with Spathulospora, a parasitic genus of the red macroalga Ballia, while the closest relatives of Halomyrma were identified as the asexual genera Halazoon and Halophilomyces (nom. inval. Art. 40.7). An analysis of published metabarcoding ITS rDNA data from environmental samples in the GlobalFungi database indicated that H.pluriseptata is widely distributed across temperate, subtropical, and tropical regions in the Northern and Southern Hemispheres. The species exhibits a strong preference for aquatic biomes, particularly marine and estuarine, with a few records in terrestrial ecosystems. In contrast, no record of T.purpureus was retrieved from GlobalFungi, suggesting narrower ecological specialisation, a close association with its seagrass host, and/or a restricted geographical range. Our findings expand the ecological and phylogenetic scope of the Lulworthiales, bridging marine and terrestrial fungal communities, and highlight seagrass roots as an important source of novel symbiotic marine fungi. Recent discoveries of the Lulworthiales in saline inland soils challenge their marine exclusivity and raise important questions about their ecological plasticity, dispersal mechanisms, and adaptive strategies. In light of current observations, we discuss the taxonomic challenges of the Spathulosporales and the lulworthialean fungi, integrating molecular and morphological perspectives. We address the importance of combining morphological and molecular approaches to accurately delineate new fungal taxa, as well as the value of environmental DNA metabarcoding for uncovering cryptic fungal diversity and enhancing our understanding of fungal distribution and ecological functions.

• Keywords
• Dictyoconidia, Thalassodendron, holoblastic conidiogenesis, marine, monilioid, new taxa, phylogenetics, saprobic, symbiotic,
• Publication type
• Journal Article MeSH

The fungal genus Cryptococcus includes several life-threatening human pathogens as well as diverse saprobic species whose genome architecture, ecology, and evolutionary history remain less well characterized. Understanding how some lineages evolved into major pathogens remains a central challenge and may be advanced by comparisons with their nonpathogenic counterparts. Integrative approaches have become essential for delimiting species and reconstructing evolutionary relationships, particularly in lineages with cryptic diversity or extensive chromosomal rearrangements. Here, we formally characterize six Cryptococcus species representing distinct evolutionary lineages, comprising both newly discovered and previously recognized but unnamed taxa, through a combination of phylogenomic analyses, divergence metrics, chromosomal comparisons, mating assays, and phenotypic profiling. Among pathogenic taxa, we formally name Cryptococcus hyracis sp. nov., corresponding to the previously characterized VGV lineage within the C. gattii complex. In parallel, we describe five saprobic, nonpathogenic species isolated from fruit, soil, and bark beetle galleries, spanning four phylogenetic clades. We identify a strong ecological association with bark beetles for Cryptococcus porticicola sp. nov., the only newly described nonpathogenic species with multiple sequenced strains from diverse sites. In this species, we detect strain-level chromosomal variation and evidence of sexual reproduction, along with population-level signatures of recombination consistent with ongoing genetic exchange. Across the genus, chromosome-level comparisons reveal extensive structural variation, including species- and strain-specific rearrangements that may restrict gene flow. We also identify multiple instances of chromosome number reduction, often associated with centromere inactivation following interchromosomal rearrangements. Comparative metabolic profiling with Biolog phenotype microarrays reveals clade-level differentiation and distinct substrate preferences, which may reflect metabolic divergence and habitat-specific diversification. Notably, we confirm that thermotolerance is restricted to clinically relevant taxa. These findings refine the species-level taxonomy of Cryptococcus, broaden its known genomic and ecological diversity, and strengthen the framework for investigating speciation, adaptation, and the emergence of pathogenicity within the genus.

• Keywords
• Fungal speciation, chromosome evolution, comparative genomics, digital DNA–DNA hybridization, human fungal pathogens, rRNA architecture,
• Publication type
• Journal Article MeSH
• Preprint MeSH

Mycorrhizal fungi are ecosystem engineers that sustain plant life and help regulate Earth's biogeochemical cycles1-3. However, in contrast to plants and animals, the global distribution of mycorrhizal fungal biodiversity is largely unknown, which limits our ability to monitor and protect key underground ecosystems4,5. Here we trained machine-learning algorithms on a global dataset of 25,000 geolocated soil samples comprising >2.8 billion fungal DNA sequences. We predicted arbuscular mycorrhizal and ectomycorrhizal fungal richness and rarity across terrestrial ecosystems. On the basis of these predictions, we generated high-resolution, global-scale maps and identified key reservoirs of highly diverse and endemic mycorrhizal communities. Intersecting protected areas with mycorrhizal hotspots indicated that less than 10% of predicted mycorrhizal richness hotspots currently exist in protected areas. Our results describe a largely hidden component of Earth's underground ecosystems and can help identify conservation priorities, set monitoring benchmarks and create specific restoration plans and land-management strategies.

• Publication type
• Journal Article MeSH

Decomposition is a crucial process in terrestrial ecosystems, driving nutrient cycling and carbon storage dynamics. Considering the amount of fungal necromass produced in soils annually, its decomposition represents an important nutrient recycling process. Understanding the decomposition dynamics and associated microbial communities of fungal necromass is essential for elucidating ecosystem functioning, especially in environmentally sensitive regions such as the Arctic tundra, which remain under-explored. In a three-year field experiment conducted in the Svalbard archipelago, we investigated the decomposition of two types of fungal necromass with differing biochemical properties. We studied the decomposition rate, changes in chemical composition, and the succession of fungal and bacterial communities associated with the decaying fungal necromass. We discovered that up to 20% of fungal necromass remained even after three years of decomposition, indicating that the decomposition process was incomplete. Our results indicate the crucial role of Pseudogymnoascus in decomposing low-quality, highly melanized necromass with a high C:N ratio in Arctic soils, underscoring its importance in carbon cycling in the Arctic tundra. Notably, we observed dynamic changes in bacterial communities, with increasing richness over time and a shift from copiotrophic to oligotrophic species specializing in decomposing recalcitrant material. Our study indicates the strong potential that fungal necromass can play in carbon sequestration of arctic soils and reveals the distinct dynamics between rather stable fungal and rapidly changing bacterial communities associated with the decomposing fungal necromass in the Arctic tundra. These findings enhance our understanding of microbial succession during decomposition in extreme environments and highlight the potentially differing roles of fungi and bacteria in these processes.

• Keywords
• Arctic tundra, Bacterial communities, Decomposition, Fungal communities, Fungal necromass,
• Publication type
• Journal Article MeSH

The nuclear ribosomal DNA Internal Transcribed Spacer (ITS) region is used as a universal fungal barcode marker, but often lacks a significant DNA barcoding gap between sister taxa. Here we tested the reliability of protein coding low-copy genes as alternative barcode markers. Mock communities of three unrelated agaric genera (Dermoloma, Hodophilus, and Russula) representing lineages of closely related species were sequenced by the Illumina platform targeting the ITS1, ITS2, the second largest subunit of RNA polymerase II gene (rpb2) and the transcription elongation factor 1-alpha gene (ef1-α) regions. Species representation and their relative abundances were similar across all tested barcode regions, despite a lower copy number in protein coding markers. ITS1 and ITS2 required more sophisticated sequence filtering because they produced a high number of chimeric sequences requiring reference-based chimera removal and had a higher number of sequence variants per species. Although clustering of filtered ITS sequences resulted in an average higher number of correctly clustered units at optimal similarity thresholds, these thresholds varied substantially among genera. Best-fitted thresholds of low-copy markers were more consistent across genera but frequently lacked species resolution due to low intraspecific variability. At some thresholds, we observed multiple species lumped together, and at the same time, species split into multiple partial clusters, which should be taken into consideration when assessing the best clustering thresholds and taxonomic identity of clusters. To achieve the best taxonomic resolution and improve species detection, we recommend combining different markers and applying additional reference-based sorting of clusters. The current availability of rpb2 and ef1-α reference sequences in public databases is far from being complete for all fungal groups, but a combined marker approach can be used for group-specific studies that can build reference data for their own purposes.

• Keywords
• amplicon abundance, chimera, sympatric species, threshold,
• Publication type
• Journal Article MeSH

Somion occarium is a wood-decaying bracket fungus belonging to an order known to be rich in useful chemical compounds. Despite its widespread distribution, S. occarium has been assessed as endangered on at least 1 national Red List, presumably due to loss of old-growth forest habitat. Here, we present a near-complete, annotated nuclear genome assembly for S. occarium consisting of 31 Mbp arranged in 11 pseudochromosomes-9 of which are telomere-to-telomere-as well as a complete mitochondrial genome assembly of 112.9 Kbp. We additionally performed phylogenomic analysis and annotated carbohydrate-active enzymes (CAZymes) to compare gene and CAZyme content across closely related species. This genome was sequenced as the representative for Kingdom Fungi in the European Reference Genome Atlas Pilot Project.

• Keywords
• cerrenaceae, polyporales, fungal conservation, saprotroph, white-rot,
• MeSH
• Wood microbiology   MeSH
• Phylogeny MeSH
• Genome, Fungal * MeSH
• Genome, Mitochondrial * MeSH
• Endangered Species MeSH
• Publication type
• Journal Article MeSH

In this study, we assessed the phylogenetic relationships among members of Ceratostomella and the morphologically similar genus Xylomelasma, currently classified within the Sordariomycetes. Our phylogenetic analyses, utilising three and five gene markers, revealed that species from these two genera are congeneric, supporting the transfer of Xylomelasma to Ceratostomella. Consequently, we propose two new combinations: C.sordida comb. nov. and C.novae-zelandiae comb. nov. In addition, we identified two cryptic species within the C.sordida species complex, which are described as C.crypta sp. nov. and C.melanospora sp. nov. Traditional micromorphological characters have proven insufficient for differentiating these new species; however, they are clearly distinguishable by molecular data, particularly using the internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) of the nuclear rRNA cistron, and genes encoding the second largest subunit of RNA polymerase II (rpb2), and translation elongation factor 1-α (tef1-α) as primary and secondary barcodes. This study provides new insights into the morphological characteristics of Ceratostomella, identifying the ascogenous system as an important diagnostic trait at the generic level, which distinguishes Ceratostomella from morphologically similar fungi. Ceratostomella is currently recognised with eight species. We also investigated the relationship between Ceratostomella and the closely related Barbatosphaeria. The lack of statistical support in the Maximum likelihood analysis is discussed and the inclusion of Ceratostomella in Barbatosphaeriaceae is not supported. Ceratostomella is accepted as a genus incertae sedis, while Barbatosphaeriaceae remains a monotypic family. The global diversity of Ceratostomella is inferred from metabarcoding data and published field observations. Biogeographic analysis indicates that members of Ceratostomella are widespread, found in soil and decaying wood, as well as in air, dust, roots, shoots, and water across temperate, subtropical and tropical regions in both the Northern and Southern Hemispheres. We are concurrently publishing whole-genome analyses of three ex-type strains of Ceratostomella, i.e. C.crypta, C.melanospora and C.sordida. This effort aims to establish a new standard for high-quality taxonomic studies, which, in accordance with current trends, should incorporate whole-genome sequencing data for future research and application. Our findings underscore the importance of integrating morphological, biogeographic and molecular data for accurate species delineation and highlight the complexity within the genus Ceratostomella.

• Keywords
• Ascogenous hyphae, Sordariomycetes, biogeography, cryptic species, molecular systematics, saprobes, two new species,
• Publication type
• Journal Article MeSH

Phylogenetic analysis of four DNA regions (ITS, LSU, mtSSU and tef1α) supported the existence of five European Taphrina species which colonise Alnus in Europe. In addition to previously well-defined species, T.viridis is, for the first time recognised, by molecular study as a species related to T.sadebeckii. Analysis of publicly available sequences of barcoding regions suggested that T.viridis is only associated with A.alnobetula and no other Taphrina species colonize this host tree. Symptomatic, morphological, and physiological characterisation of T.viridis are provided together with the key for identification of Alnus associated Taphrina species in Europe and North America.

• Keywords
• Alder, Exoascus, culture characterisation, identification key, morphology, taxonomy, witches’-brooms,
• Publication type
• Journal Article MeSH

While the succession of terrestrial plant communities is well studied, less is known about succession on dead wood, especially how it is affected by environmental factors. While temperate forests face increasing canopy mortality, which causes considerable changes in microclimates, it remains unclear how canopy openness affects fungal succession. Here, we used a large real-world experiment to study the effect of closed and opened canopy on treatment-based alpha and beta fungal fruiting diversity. We found increasing diversity in early and decreasing diversity at later stages of succession under both canopies, with a stronger decrease under open canopies. However, the slopes of the diversity versus time relationships did not differ significantly between canopy treatments. The community dissimilarity remained mainly stable between canopies at ca. 25% of species exclusively associated with either canopy treatment. Species exclusive in either canopy treatment showed very low number of occupied objects compared to species occurring in both treatments. Our study showed that canopy loss subtly affected fungal fruiting succession on dead wood, suggesting that most species in the local species pool are specialized or can tolerate variable conditions. Our study indicates that the fruiting of the fungal community on dead wood is resilient against the predicted increase in canopy loss in temperate forests.

• Keywords
• Canopy mortality, Climate change, Dead wood, Forest management, Fungi, Microclimate, Succession,
• MeSH
• Biodiversity * MeSH
• Wood * microbiology   MeSH
• Fungi * MeSH
• Forests * MeSH
• Fruiting Bodies, Fungal growth & development   MeSH
• Trees microbiology   MeSH
• Publication type
• Journal Article MeSH

How the multiple facets of soil fungal diversity vary worldwide remains virtually unknown, hindering the management of this essential species-rich group. By sequencing high-resolution DNA markers in over 4000 topsoil samples from natural and human-altered ecosystems across all continents, we illustrate the distributions and drivers of different levels of taxonomic and phylogenetic diversity of fungi and their ecological groups. We show the impact of precipitation and temperature interactions on local fungal species richness (alpha diversity) across different climates. Our findings reveal how temperature drives fungal compositional turnover (beta diversity) and phylogenetic diversity, linking them with regional species richness (gamma diversity). We integrate fungi into the principles of global biodiversity distribution and present detailed maps for biodiversity conservation and modeling of global ecological processes.

• MeSH
• Biodiversity MeSH
• Ecosystem * MeSH
• Phylogeny MeSH
• Fungi genetics   MeSH
• Humans MeSH
• Soil * MeSH
• Soil Microbiology MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Soil * MeSH