Mycologia最新文献

The new species Stereophlebia arizonica from southern Arizona is described and illustrated. Although similar to S. pendula, a widely distributed taxon in North America, molecular phylogenetic analyses and morphological evidence show that they are distinct, sister species. Phylogenetic analyses place Stereophlebia in a clade with Gelatinofungus within the Phanerochaetaceae (Polyporales). Critical morphological features of Gelatinofungus not reported earlier are presented, and G. betulinus is determined to be a later synonym of S. pendula.

This study describes a novel parasitic fungus that infects the benthic and epiphytic dinoflagellate Ostreopsis cf. ovata during a coastal microalgal bloom in the Mediterranean Sea. Microscopic observations revealed a distinctive, irregularly shaped zoosporangium during the mature stages and spherical, posteriorly uniflagellate zoospores. This supports its affiliation within the phylum Chytridiomycota. Concatenated phylogenetic analysis based on 18S, 5.8S, and 28S ribosomal DNA placed the fungus within the order Lobulomycetales, thus establishing it as a distinct lineage separate from previously described species. Additional phylogenetic analyses including environmental DNA sequences revealed a close phylogenetic relationship with previously reported freshwater sequences. This suggests a possible ecological link between marine and freshwater habitats. Cross-infection experiments confirmed the ability of the fungus to infect healthy cells of both dinoflagellate and diatom species, rendering it the first known chytrid with a broad phytoplankton host range. Additionally, it is the first member of this order known to parasitize dinoflagellate species and only the second known to parasitize marine algae. Infection prevalence was higher in dinoflagellates than in diatoms. Furthermore, under laboratory conditions, the chytrid also developed zoosporangia on pollen grains, using them as an alternative nutrient source. Based on these findings, this study describes a new genus and species of zoosporic fungus, Algophthora mediterranea, within the order Lobulomycetales.

Truffles are enclosed, hypogeous fruiting bodies that have evolved hundreds of times across different fungal groups. Truffles are particularly diverse within Pezizales, a large and diverse order of Ascomycota where truffle forms have evolved multiple times. The majority of truffle species are ectomycorrhizal symbionts of trees and rely on animals for dispersal. Because of their hypogeous nature, truffles remain understudied and many new taxa remain to be discovered. Due to their obligate symbiosis with host plants and their dependence on animal dispersal, ectomycorrhizal truffle species often show distinct host associations, are restricted to certain forest types, and have notable biogeographic distribution patterns. Here, we present morphological and phylogenetic evidence in support of two new truffle species associated with Nothofagaceae trees in southern South America, Geomorium nahuelbutense (Geomoriaceae) and Paragalactinia nothofagacearum (Pezizaceae). The closest described relatives of these species form aboveground, apothecial ascomata, suggesting that these taxa are derived from independent evolutionary events leading to the truffle morphology. Paragalactinia nothofagacearum is widespread in northern Patagonia and has been documented as an ectomycorrhizal associate of Lophozonia alpina (= Nothofagus nervosa) seedlings. In contrast, Geomorium nahuelbutense has only been found in a well-preserved coastal forest in Chile toward the northern extent of the range of Nothofagaceae in South America. This is a conservation priority area that has been heavily impacted by fires, deforestation, and other human activities. This species is known only from two modern collections from Parque Nacional Nahuelbuta and one preserved specimen collected by Roland Thaxter near Concepción, Chile, in 1906.

Anaerobic gut fungi (AGF; Neocallimastigomycota) are a clade of basal, zoospore-producing fungi within the subkingdom Chytridiomyceta and known inhabitants of the alimentary tract of animal hosts. To date, 22 genera and 38 species have been described, most originating from herbivorous mammals. Here, we report on the isolation and characterization of a novel species of Neocallimastigomycota from an avian host. Multiple AGF strains were isolated from ostrich feces obtained from a local farm in Oklahoma (USA). All strains formed small, irregular-shaped white colonies with darker centers, displayed a filamentous rhizoidal structure with monocentric thallus developmental patterns, and produced mostly monoflagellated zoospores. The type strain produced terminal sporangia that were predominantly globose, often exhibiting cup-shaped and occasionally elongated sporangiophores. Sporangiophores characteristically exhibited constrictions at irregular intervals, giving them a beads-on-a-string-like appearance. Phylogenetic analysis using the partial nuc 28S rDNA D1-D2 regions (D1-D2 28S), ribosomal internal transcribed spacer 1 (ITS1), and RNA polymerase II large subunit (RPB1) grouped all isolates as a separate species within the genus Piromyces. Transcriptomic analysis indicated an average amino acid identity (AAI) of 80.34% (± 3.27%) between the type species and members of the genus Piromyces and 62.93-76.05% between the type species and all other AGF taxa outside Piromyces. Based on the morphology, phylogenetic analysis, and AAI values, we propose accommodating these strains as a novel species of Piromyces, for which the name Piromyces struthionis is proposed. The type strain for this species is Ost1.

The family Nectriaceae includes numerous phytopathogenic fungal genera that cause canker diseases on both angiosperm and conifer hosts worldwide. Among these, Neonectria species are globally important canker pathogens of numerous plant hosts, but their roles in contributing to forest decline and mortality outside their involvement in beech bark disease and apple canker are largely understudied. In the U.S.A. N. magnoliae causes perennial cankers on two native hosts in central Appalachia: Liriodendron tulipifera (tulip poplar) and Magnolia fraseri (Fraser magnolia) and has been recently confirmed from non-native M. stellata (star magnolia) in West Virginia, U.S.A. Both native hosts occur in the central Appalachian Mountains, but M. fraseri occurs mostly at higher elevations, from 600 to 1700 m. Neonectria magnoliae was first described in 1943 (as Nectria magnoliae), yet its impact across the forested landscape remains unclear. To clarify host-specific differences across the contemporary range of N. magnoliae, we used multilocus phylogenetics, comparative pathogenicity/virulence assays, and morphological analyses to determine whether N. magnoliae represents two cryptic species that specialize on L. tulipifera and Magnolia spp. or whether N. magnoliae has host-specific pathotypes. Our studies revealed two morphologically distinct formae speciales within N. magnoliae: (i) N. magnoliae f. sp. liriodendri-strains originating from L. tulipifera with increased virulence on L. tulipifera and lacking macroconidia production and (ii) N. magnoliae f. sp. magnoliae-strains originating from M. fraseri with increased virulence on M. fraseri and producing macroconidia readily in culture. Overall, the incidence of these two pathotypes indicates that neither pathotype poses serious risks to either plant host but can add to cumulative stresses that both tree species are experiencing in the face of shifting global weather patterns.

Panaeolus oligotrophus sp. nov., a species macromorphologically resembling Panaeolus cinctulus, was collected in central Florida. Its macro- and micromorphological features are described and compared with all other known Panaeolus species. Color photos of the fruiting bodies and micrographs of key microscopic features are provided, along with an updated phylogenetic analysis. A microscopic reexamination of the holotype of Panaeolus pumilus supports its synonymy with P. cinctulus. The potential for psilocybin production by P. oligotrophus was determined by the characterization of the psilocybin gene cluster through whole genome sequencing. Phylogenetic and morphological evidence also supports the placement of Crucispora rhombisperma within Panaeolus, for which the new combination Panaeolus rhombispermus is proposed. This paper makes two interesting additions to the genus Panaeolus: P. rhombispermus introduces the novelty of an extremely differentiated spore morphology, and Panaeolus oligotrophus provides a rare example of Panaeolus in the underexplored niche of oligonutritive sandy soil.

The emergence of Candida auris, a multidrug-resistant fungal pathogen with unique heterogenic characteristics and clades, raised significant concerns globally, particularly in healthcare settings. C. auris pathogenicity resides in its adaptability and resilience, with the ability to form robust biofilms and adhere to host tissues and medical devices. Adhesins, particularly Als3, primarily mediate these processes. This review explores the variations in expression, copy numbers, and genetic modifications of Als3 in relation to different clades and environmental conditions. Furthermore, the role of Als3 in adhesion, biofilm formation, and invasion is discussed, in addition to its contribution to immune evasion and fungal virulence. Expression profiles of Als3 and copy numbers play important roles in fungal heterogeneity, aggregation, and pathogenicity, with high expression and copy numbers imposing significant effects. Gene mutation, transcriptional and translational controls of Als3, in addition to three-dimensional structure in C. auris, are areas of limited information. The potential of targeting Als3 for therapeutic interventions is also reviewed, including approaches such as the use of C. albicans Als3 vaccine, antibodies, natural ligands, and others, although research in this area is still limited. Future research directions should include in-depth investigation of Als3 structural and molecular differences, in addition to the discovery of target drugs.

Invasive and weedy plants proliferate in disturbed areas, including the margins of agricultural fields where they can be alternative hosts and reservoirs of crop pathogens. Research on plant pathogens focuses on economically important plants, whereas pathogens of weedy and invasive grasses are generally less well characterized. Bipolaris species have the potential to cause disease on many plant species and are common pathogens of grasses and crops in the family Poaceae. This study aimed to identify Bipolaris species causing foliar lesions on common weedy and invasive grasses in disturbed and natural areas in four counties in Florida. Isolation of characteristic Bipolaris conidia from sampled grasses resulted in 22 isolates. Maximum likelihood phylogenetic analysis of internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase (GPDH) gene sequences from these isolates identified four Bipolaris and one Curvularia species. B. yamadae was the most common species recovered, followed by B. sorokiniana, B. cynodontis, and B. zeae. To determine whether the Bipolaris isolates were potential crop pathogens, we tested their pathogenicity on seedlings of wheat cultivar "Jamestown." All Bipolaris isolates tested caused moderate to severe disease. Our results indicate that invasive and weedy grasses support populations of Bipolaris pathogens of crops. Knowledge of pathogen natural history can inform management of existing and emerging crop diseases.

Many species in Rhytismataceae exhibit distinct host specificity. The present study focuses on Rhytismataceae associated with needles of Juniperus species. Based on analyses of morphology, phylogeny, and ecology, the new genus Bifusiformispora is proposed, along with five new species: Bifusiformispora ovalis, B. lucida, B. opaca, Hypoderma rostratum, and Lophodermium germanicum. In addition, two new combinations, Bifusiformispora junipericola and Lophodermium junipericola, are proposed. Finally, a key to Rhytismataceae species on Juniperus needles worldwide is provided.