Mycologia最新文献

Native to South America, moth plant (Araujia hortorum, Apocynaceae) is an invasive vine that threatens natural ecosystems and agriculture in many parts of the world. Biological control studies involving fungal pathogens have primarily focused on the rust Puccinia araujiae, but other aggressive pathogens exist that may show potential as complementary agents. In its native range in Argentina, plants were quite frequently observed with severe leaf and fruit damage caused by a fungal disease. The pathogen associated with this disease was isolated and identified as Septoria araujiae based on morphological analyses. Multilocus analyses allowed the first phylogenetic placement of this species within the genus. Koch's postulates were fulfilled through inoculation experiments, confirming S. araujiae as the causal agent. The pathogen exhibited a hemibiotrophic life cycle, with an extended asymptomatic phase followed by a necrotrophic stage that led to severe defoliation. Host specificity experiments revealed a narrow host range, with susceptibility largely confined to species within the subtribe Oxypetalinae. These findings contribute new insights into the diversity, ecology, and host interactions of Septoria species and highlight the potential of S. araujiae as a biological control agent for A. hortorum.

A rarely collected rose-pink-colored Hericium americanum has now been documented with in situ images obtained by 11 different field naturalists in the northeastern United States and eastern Canada since 2018. These mushroom enthusiasts responded to a request for images and specimens of a rarely documented rose-pink-colored tooth fungus discussed in the comments section of a description of Hericium americanum and H. coralloides in Mushrooms of the Northeastern United States and Eastern Canada. Five of those finds were collected, preserved by drying, and sent to the authors for analysis. This strikingly colored tooth fungus is confirmed as a variant of H. americanum using morphological and molecular data (nuc rDNA ITS1-5.8S-ITS2 and partial nuc 28S rDNA D1-D6 regions) and proposed here as a new variety.

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.

Filamentous fungi produce secondary metabolites with multiple biochemical activities. For wood-decaying fungi of Basidiomycota, some of these compounds may act as redox-active mediators involved in biodegradation of lignocelluloses and biopolymers. Our aim was to identify natural aromatic compounds produced by white rot fungi of the genus Phlebia (Meruliaceae, Polyporales, Agaricomycetes), which comprises efficient decomposers of wood, wastes, and xenobiotics. Naturally produced aryl compounds were obtained by cultivating the fungi on a defined low-nitrogen liquid medium with glucose as carbon source. Culture supernatants were extracted and analyzed with UPLC-MS (ultra-performance liquid chromatography-mass spectrometry) and NMR (nuclear magnetic resonance). Enzyme assays, cultivation with ¹⁵N isotope-labeled nitrogen supplement, and aryl compound-feeding experiments were performed to assess biosynthesis mechanisms. Together with the well-known secondary metabolite veratryl alcohol and its enzymatic oxidation product veratraldehyde, we identified two nitroaryl derivatives, 6-nitroveratryl alcohol and 4-nitroveratrole, accumulating in culture supernatants of Phlebia spp. Cultivation of P. radiata isolate 2776 with NH₄NO₃ caused higher product yield of the nitroaryl compounds than ¹⁵NH₄Cl supplementation, suggesting a role of nitrate ions in formation of nitroaryl products. With ¹⁵N-labeled supplementation, however, incorporation of nitrogen also from ammonium ions was observed. Although lignin peroxidase (LiP) enzyme activities correlated with appearance of nitroaryl compounds, their formation from veratryl alcohol by LiP was not accomplished in vitro in reaction mixtures with extracellular supernatants. In compound-feeding experiments, additional glycosylated derivative of 6-nitroveratryl alcohol was detected in P. radiata cultures, and nitroguaiacol was formed from nitroveratrole. These results indicate multiple pathways including both intra- and extracellular metabolism in biosynthesis and bioconversion of monoaromatic aryl compounds and their derivatives in fungi of Phlebia.

Ectomycorrhizal (ECM) fungi are widely recognized for their ability to enhance plant survival and growth under saline conditions. Although extensive research has focused on the development of salt-tolerant ECM fungal strains, the cytological and morphological responses of ECM fungi to salt stress remain unclear. Moreover, the cellular mechanisms underlying fungal adaptation to high-salinity conditions remain poorly understood. This study investigated salinity tolerance and cellular adaptations of three R. roseolus strains subjected to increasing artificial seawater concentrations. The mycelia were grown on modified Melin-Norkrans (MMN) medium containing 0%, 50%, or 100% artificial seawater then observed under a phase-contrast light microscope. The hybrid strain TUFC102052 exhibited the highest tolerance to 50% artificial seawater, whereas significant growth inhibition was observed in both the wild-type strain TUFC10010 and the salt-sensitive strain TUFC102053 at higher salinity levels. Cellular alterations including subterminal cell size reduction and vacuole fragmentation were observed, indicating potential adaptive strategies for survival under saline conditions. These findings provide new insights into the morphological adaptations of the ECM fungus R. roseolus to salt stress.

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.