Mycologia最新文献

The role of microfungal species in the environment is wide and well documented, especially in terms of symbiosis. Nonetheless, microfungal species are usually overseen and vastly understudied. One example of these understudied microfungal groups is the genus Basidiobolus, an ecologically diverse zoopagomycete genus found within vertebrate gastrointestinal systems, a saprobe across leaf litter, or as an opportunistic pathogen of immunocompromised humans. Studies of Basidiobolus diversity and distribution have been focused mostly on non-urbanized areas of subtropical regions, but there is a recent paucity of studies on this genus in temperate and densely human populated areas. Here, we present insights into the ubiquity and diversity of Basidiobolus species associated with amphibian species that live in the Worcester waterway system, a system of connecting streams and ponds that originate in pristine, protected wild management areas, and the highly urbanized downtown area of Worcester, Massachusetts. Our results show the ubiquitous presence of Basidiobolus across the gastrointestinal tract samples of amphibians spanning diverse species and habitats, including conservation areas, urban watersheds, and rural ecosystems. Our study reveals that multiple individuals and species of Basidiobolus coexist within a single host, suggesting complex interactions within amphibian gut microbiomes. Finally, we present possible novel diversity in the genus, indicating that further studies should be focused on understanding the species richness, genetic diversity, and ecological roles and associations of this interesting fungal group.

Fungal biologists have embraced phylogenies for understanding the biology of this diverse group in an evolutionary framework. In an attempt to highlight lineages of fungi that are distinct from the most speciose subphylum Dikarya (Ascomycota + Basidiomycota), the terms "early diverging fungi [lineages]" and "basal fungi" have been introduced, typically to refer to any phylum of fungi outside Dikarya. However, these terms are problematic, because they implicitly assume that the traits and taxa outside of Dikarya are ancestral by invoking a "ladder of progress." A simple rearrangement of the tree to deemphasize the species-rich Dikarya shows that the logic that these taxa are "early branching" or "basal" is a fallacy, because it ignores two facts: (i) that all extant lineages of fungi have evolved an equivalent amount of time since a last common fungal ancestor, and (ii) that the "early diverging lineages" are no more related to each other than they are to Dikarya. To support the many mycologists who want to celebrate the understudied lineages outside of Dikarya while ensuring that these lineages are not mistakenly perceived as "less evolved," "more ancient," or of "lower complexity," we propose that the community abandon these terms and simply use formal taxonomic names, e.g. Mucoromycota. Doing so will promote knowledge of these often overlooked branches of the tree of fungal life.

Urban expansion, projected to triple globally from 2000 to 2030, significantly impacts biodiversity and ecosystem processes, including those of microbial communities. Microbes are key drivers of many ecosystem processes and affect the fitness and resilience of plants and animals, but research on the biotic effects of urbanization has focused primarily on macroorganisms. This study investigates host-associated fungal communities in the pollution-tolerant aquatic plant Ranunculus aquatilis along an urbanization gradient in the Provo River, Utah, USA, a rapidly urbanizing region. We collected plant and adjacent water samples from 10 locations along the river, spanning from rural to urbanized areas within a single watershed, and conducted DNA amplicon sequencing to characterize fungal community composition. Our results show a significant decline in fungal alpha diversity correlated with increased urbanization metrics such as impervious surface area and developed land cover. Specifically, fungal richness and Shannon diversity decreased as urbanization intensified, driven primarily by a reduction in rare taxa. Despite a stable core microbiome dominated by a few taxa, the overall community structure varied significantly along the urbanization gradient, with notable shifts in dominant fungal taxa. Contrary to expectations, no detectable levels of heavy metals were found in water samples at any location, suggesting that other urbanization-related factors, potentially including organic pollutants or plant stress responses, influence fungal endophyte communities. Our findings underscore the need for further investigation into the mechanisms driving these patterns, particularly the roles of organic pollution, nutrient loads, and plant stress. As global urbanized watershed area grows, the fate of aquatic plant life is tied to their fungal community. Understanding these interactions is crucial for predicting the impacts of continued urbanization on freshwater ecosystems.

Curvularia species exhibit a wide range of ecological roles, including plant, animal, or human pathogens, as well as epiphytes, saprophytes, or endophytes, predominantly associated with cultivated cereals. In this study, several fungal isolates with similar characteristics in the genus Curvularia were recovered from various poaceous hosts (Poales plants) in different locations in Iran during 2012‒2022. Based on the morphological characteristics and multilocus phylogeny of the translation elongation factor-1 alpha (TEF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and the internal transcribed spacer (ITS-rDNA) genes, the studied isolates were assigned to five species, of which Curvularia caspica, sp. nov. and C. cyperi, sp. nov. are introduced as novel species and Curvularia nodulosa and C. oryzae are new records for Iran's mycobiota. Molecular studies revealed a closer relationship between one of the studied species (Curvularia sp.) and C. frankliniae. However, due to the absence of detailed morphological characteristics for C. frankliniae, morphological comparisons were not feasible. To precisely establish their phylogenetic position, more isolates need to be analyzed. Consequently, the studied species was identified as Curvularia sp. in this study. Additionally, a new clade, "papendorfii," was established to accommodate 11 species that share common morphological characteristics and form a distinct clade in phylogenetic analyses. The morphology, habitat, distribution, and evolutionary relationships of each species with other Curvularia species were analyzed, accompanied by detailed illustrations and descriptions. This comprehensive study offers valuable insights into the diversity and distribution of Curvularia species, enhancing our understanding of fungal ecology and taxonomy.

This study examined fungi with Xylaria-like morphology on submerged decorative wood in freshwater aquariums in Minnesota and Colorado. The wood was sold in retail stores in the United States but originated from Asia. The submerged wood had black stromatic melanized structures with white tips that grew out from the wood. As colonization progressed, the fungus produced more melanized structures along the entire length of the wood and moved to new wood placed in the aquariums. Cut segments from the fungal structures and from the colonized wood were cultured in malt extract agar supplemented with antibiotics. Pure cultures obtained were used for DNA extraction, and polymerase chain reaction (PCR) amplification was performed using ITS1F-ITS4. Sequences were compared against the National Center for Biotechnology Information (NCBI) nucleotide database using BLASTn. Isolates from the fungal structures and wood obtained from the Minnesota and Colorado aquariums were all found to be Xylaria apoda, a fungus not previously reported from the United States. Phylogenetic analysis shows that the aquarium isolates of Xylaria cluster within a well-supported clade of Xylaria apoda. These Xylaria had grown in a completely aquatic habitat, producing fruiting body-like structures for several years in the freshwater aquariums. Asexual spores were not observed but may have been disseminated into the water as they are formed. Asci and ascospores were also not observed. Xylaria apoda has been reported only from Asia, and it is usually found in terrestrial habitats. This report adds to our knowledge of Xylaria that can grow in a completely underwater environment and focuses attention on an avenue for exotic fungi to be brought into new countries where they are not native. These results also contribute to the growing body of evidence that X. apoda is an ecologically versatile species, capable of thriving in diverse environments, including artificial habitats such as freshwater aquariums.

Southeast Qinghai-Tibet Plateau, which harbors large numbers of marine glaciers and spans across two worldwide "biodiversity hotspots," is facing massive habitat loss in the context of global warming, and the biodiversity of coldadapted fungi in this unique area is also suffering drastic reduction. In this study, we selected 23 fungal isolates that represented the most commonly encountered psychrophilic taxa isolated from soil or water samples of marine glaciers in the southeast Qinghai-Tibet Plateau for detailed taxonomic studies. Incorporating morphological characteristics, multilocus phylogenetic analyses, and the results of four widely used molecular species delimitation methods, including two distance-based: Automatic Barcode Gap Discovery (ABGD) and Assemble Species by Automatic Partitioning (ASAP), and two tree-based: Bayesian Poisson Tree Processes (bPTP) and generalized mixed Yule coalescent model (GMYC), seven Gelida (formerly Psychrophila) species, including six new species, and two Tetracladium species, including one new species, were described. As the genus name Psychrophila is an illegitimate later homonym of a plant genus, we proposed the new name Gelida as a replacement for Psychrophila and transferred four illegitimate Psychrophila species to Gelida as new combinations. Our study provides a valuable perspective on how to delimit robust and accurate species boundaries within an integrative taxonomic framework, which is especially important for efficient biodiversity assessment and conservation of the fungal groups that are facing serious habitat loss.

The lifestyles of the order Geoglossales (Geoglossomycetes, Ascomycota) remain largely unknown. Recent observations support ericoid mycorrhizal lifestyles, especially in cultured Sarcoleotia-related species. However, the currently known genomes of geoglossoid fungi encode fewer carbohydrate-active enzymes (CAZymes) in Pezizomycotina, in contrast to the abundant CAZyme repertoires found in well-known ericoid mycorrhizal fungi. The absence of assembled genomes for cultured geoglossoid fungi hinders our understanding of the genomic features related to their lifestyles. We hypothesize that the genome of Sarcoleotia globosa, a putative ericoid mycorrhizal fungus, encodes abundant CAZymes, consistent with its culturability. General features, such as smaller genome size and smaller number of genes, are shared between the genome of S. globosa strain NBRC 116039 and other geoglossalean genomes. However, the former had the most extensive CAZyme repertoire, with several enzyme families involved in plant cell wall degradation. Some of these CAZymes are not found in Geoglossales and closely related lineages. Nonetheless, the number of CAZymes from S. globosa was notably smaller than that previously reported in ericoid mycorrhizal fungi. This inconsistency may highlight not only ecophysiological variation among ericoid root mycobionts but also the specific evolution of lifestyles in Geoglossales.

In this study, Minimedusa polyspora and Chaetomium globosum and their metabolites were assessed in vitro for their ability to inhibit growth of Alternaria alternata, Berkeleyomyces basicola, and Botrytis cinerea, gaining insights into their biocontrol mechanisms. A dual culture, an assay for volatile antimicrobial compounds effectiveness (performed in two different conditions), and a culture filtrate antifungal assay were designed to discriminate the involved mechanisms. Moreover, the culture filtrates of these strains were assessed for fungistatic and fungicidal activities (determining also the minimum inhibitory concentration and the minimum fungicidal concentration) and for the occurrence of siderophores. The results show that both M. polyspora and C. globosum inhibited, to different extents, growth of all the pathogens in the plate assays. Both culture filtrates showed fungistatic and fungicidal activities, pointing to the release of diffusible compounds as an involved biocontrol mechanism. Based on the results of this study, M. polyspora and C. globosum are promising bioprotection agents of these phytopathogens and species of interest for further studies aimed at validating their potential in in vivo conditions.

Despite being present in many North American forest understories, the ectomycorrhizal (ECM) fungal communities associated with Corylus shrubs have received no prior study. To address this knowledge gap, we characterized the ECM fungal communities on roots of Corylus shrubs as well as co-occurring Quercus and Pinus trees in Minnesota, USA. ECM-colonized root tips from pairs of Corylus shrubs and four ECM tree species, Quercus macrocarpa, Quercus ellipsoidalis, Pinus strobus, and Pinus resinosa, growing in close proximity (<1 m), were sampled at the Cedar Creek Ecosystem Science Reserve. ECM fungal communities were assessed using high-throughput sequencing of the ITS2 region. ECM fungal operational taxonomic unit (OTU) richness was equivalent among the two Quercus species and their associated Corylus shrubs, but significantly higher on P. strobus-associated Corylus shrubs compared with P. strobus, P. resinosa, and P. resinosa-associated Corylus shrubs. ECM fungal community composition on Corylus shrubs largely mirrored that on each of the Quercus and Pinus species, although the two Pinus communities were significantly different from each other. Further, the same ECM fungal OTUs were commonly encountered on paired Corylus-tree host samples, suggesting a high potential for co-colonization by the same fungal individuals. Collectively, these results support the growing consensus that woody understory plants often associate with similar ECM fungal communities as co-occurring tree hosts regardless of phylogenetic relatedness.

Fungal trunk diseases are of major concern for tree fruit, nut, and grape growers throughout the world. These diseases include Eutypa dieback of grape, caused by Eutypa lata, band canker of almond, caused by Neofusicoccum mediterraneum and Neofusicoccum parvum, and twig and branch dieback of walnut, caused by N. mediterraneum, Botryosphaeria dieback of grape, caused by Diplodia mutila, Diplodia seriata, N. mediterraneum, and N. parvum, and esca of grape, caused by Phaeomoniella chlamydospora and Phaeoacremonium minimum. Given the common occurrence of mixed infections, and the similar wood symptoms at the macroscopic level, species-specific detection tools are needed. Fatty acid methyl ester (FAME) profiling can be an effective and inexpensive diagnostic tool. FAME analyses were conducted on pure cultures of multiple isolates per species to characterize profiles and assess whether this technique could result in consistent identification. FAME profiles were dominated by oleic acid (18:1 ω9c) and palmitic acid (16:0), with less abundant FAMEs in different ratios for each species and isolates within species. Canonical discriminant analyses revealed which minor FAMEs were most variable, with a total of 20 different FAMEs that can explain 69.01% of profile variance in the first two canonicals. Using these analyses, samples were self-tested and correctly sorted 97.18% of the time. Within species, canonical discriminant analyses were able to separate isolates further, often by original geographic location or by host plant species. These results further suggest that potential novel species, subspecies, or races may be present among the isolates analyzed, demonstrating the capacity of FAME profiling to have a role in discovering cryptic species and accurately identifying fungal pathogens in conjunction with other molecular techniques and genomic analyses.