Mycologia最新文献

Pleoscrubia floridana, sp. nov. included in Pleoscrubia, gen. nov. isolated from roots of the Florida endemic Paronychia chartacea (paper nailwort; Caryophyllaceae), is described. Multigene phylogenetic analyses suggest that the fungus represents a novel lineage and along with morphological and ecological characteristics support the description of Pleoscrubiaceae, fam. nov. within Pleosporales (Dothideomycetes) to accommodate this distinct genus and species. Pleoscrubia floridana is likely unique to the Florida scrub ecosystem and associated with Paronychia chartacea host. The plant-fungal interaction experiment yielded neutral results on Arabidopsis thaliana. This newly discovered fungal lineage will help researchers understand the diversity and systematics of Pleosporales.

Mucormycosis is a group of diseases that is increasing in frequency. A common opportunistic human fungal pathogen in this group is Rhizopus microsporus, which is a globally distributed species present in soil-associated environments. A subset of isolates in this species host endobacteria that are hypothesized to influence fungal pathogenicity in both clinical and environmental settings. We have limited understanding of how clinically and environmentally derived isolates are related or how physiological attributes, including thermotolerance and endosymbiosis, are correlated with population structure. Traditional molecular barcodes used to assess intraspecific relationships, such as ribosomal DNA internal transcribed spacer (ITS-rDNA)-based markers, do not provide species-level resolution, necessitating analyses of whole genome data. In this study, we generated novel whole genome sequencing data for six R. microsporus isolates and combined these data with publicly available whole genome sequences of 46 R. microsporus isolates. We evaluated these sequences to understand the evolutionary relationships among clinical and environmental isolates using phylogenomic and single nucleotide polymorphism (SNP)-based population genomics methods. We further studied their relationships by quantifying and comparing potential physiological differences and endosymbiont presence in a subset of 16 isolates with live cultures. We found that clinical isolates that originate from environmental settings contain higher molecular diversity than subpopulations isolated from clinical settings. We observed that environmental isolates grow faster than clinical isolates at temperatures between 22 and 37 C and that 7 of 16 (44%) contain endobacteria in the genus Mycetohabitans (Burkholderiales). Lastly, we observed that genome assembly size in R. microsporus is variable and that long-read sequencing technologies greatly enhance our ability to investigate the underlying genomic features. Our study provides a valuable backdrop for probing the basic biology and applied biomedical importance of Rhizopus and related fungi that cause mucormycosis.

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.

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.

Five strains of Cunninghamella were isolated from Amazon forest soils in the state of Amazonas, Brazil. Strains URM 9031 and URM 9187 form sporophores with main axes ending in a vesicle or dividing into several branches with globose to subglobose sporangiola. Lateral branches can rebranch up to four times. The maximum temperature growth (Tmax) is 38 C. Strains URM 9032, URM 9199, and URM 9108 form axial sporophores ending in a vesicle or forked, with lateral branches rebranching up to four times; sporangiola are exclusively globose. The Tmax is 41 C. Based on distinct morphologies, along with physiological and multilocus phylogenetic evidence of the nuc rDNA regions ITS1-5.8S-ITS2 (internal transcribed spacer [ITS]) and partial D1-D2 domains (28S) and the elongation factor-1 alpha (EF-1α) gene, Cunninghamella ramificata sp. nov. and C. amazonica sp. nov. are proposed. A taxonomic discussion of both new species and an updated identification key for the Cunninghamella are provided.

Two smut fungi infecting the crinkle-awn grass Trachypogon spicatus (Poaceae) in Africa are characterized morphologically, illustrated, and linked to DNA barcodes (rDNA ITS, 28S). Sporisorium trachypogonis-spicati is reported for the first time from Benin, South Africa, and Togo, far from the previously known localities in the Democratic Republic of the Congo and Zimbabwe. This species is morphologically similar and closely related but genetically divergent to Sporisorium trachypogonicola, which infects Trachypogon spicatus in the Americas. Tilletia afrotrachypogonis is described as a new species from Togo and is also known from southeastern Africa (Malawi, Zambia). This species is morphologically almost identical to but genetically distinct from Tilletia trachypogonis, which infects Trachypogon spicatus in Mexico. The phylogenetic sister relationship, phenotype, and ecological similarity for the two species pairs Sporisorium trachypogonis-spicati/S. trachypogonicola and Tilletia afrotrachypogonis/T. trachypogonis, but occurrence in different geographic areas (Africa and the Americas/North America, respectively), suggest a common ancestral species, allopatric speciation, and duplication, i.e. speciation on the same host species.

Bird's nest fungi (Nidula candida) growing along ~18-year-old cedar fences in Pacific Spirit Regional Park, Vancouver, British Columbia, Canada, produce abundant, persistent peridia containing basidiospore-bearing, egg-like peridioles. To reconstruct the initial mode of reproduction of the populations, 37 peridia were collected following a geometric sampling design, with 8-10 peridia collected 6-222 cm apart from each of four fence segments. We cultured dikaryotic mycelium from one whole peridiole from each peridium and 105 monokaryons from basidiospores from 8 peridioles. We then tested mycelial compatibility by confronting pairs of dikaryons and sexual compatibility by mating the monokaryons from basidiospores. The resulting genetic patterns allowed us to map genetic individuals back to their fence segments. The dikaryotic mycelia that grew from whole peridioles fell into six mycelial compatibility groups, with one or two groups per 3-7 m fence segment. Consistent with an outcrossing origin, four different mycelial compatibility groups had different mating types. The largest compatibility group covered over 6 m of fence, producing 114 peridia and ~4.2 billion spores. One compatibility group was present at two fence sites ~40 m apart, suggesting asexual dispersal. This can potentially be explained by somatic growth from the walls of dispersed peridioles. Dikaryons generated by mating sibling monokaryons isolated from basidiospores from the same peridiole showed mycelial incompatibility in 86% of pairings. Thus, the compatible dikaryotic mycelia emerging from whole peridioles likely represent clones of parental mycelium rather than recombinant meiotic hyphae from basidiospores. Asexual reproduction from dispersed fruit body tissue is unusual in Agaricales, but in N. candida fence-hopping of peridioles splashed from peridia and germinating as clonal, parental-type dikaryotic mycelia may have contributed to expansion of a genet along the fence.

The genus Nucleophaga comprises poorly studied intranuclear parasites that infect amoebae. Currently classified within the phylum Rozellomycota, this genus belongs among numerous lineages with unresolved taxonomic positions, primarily identified through metagenomic studies. Three species of Nucleophaga were described at the morphological and molecular levels-N. amoebae, N. terricolae, and N. striatae, all isolated in Europe. Here, we report the discovery of a fourth species of the genus, isolated from the Far East of Russia, infecting nuclei of Thecamoeba sp. A detailed light microscopic study revealed several remarkable morphological features of this organism. For the first time, the division of Nucleophaga plasmodium was illustrated. Experimental infections demonstrated that Thecamoeba quadrilineata and T. foliovenanda can support the development of the parasite, whereas Nucleophaga showed abnormal development in T. onigiri and was unable to survive in T. vumurta. Phylogenetic analysis, based on the nuc 18S rRNA gene sequences, placed the new isolate as a distinct lineage within the genus Nucleophaga. Based on its molecular characteristics, the studied isolate was described as a new species, Nucleophaga amutiana.

Clitocybaceae, currently recognized in the suborder Tricholomatineae, has undergone significant taxonomic reevaluation through phylogenetic, phylogenomic, and morphological analyses. In this study, we surveyed the species diversity of Clitocybaceae in Shanxi Province, northern China. Phylogenetic analyses were performed using ITS (internal transcribed spacer) and six loci including ITS, 28S (large subunit ribosomal), tef1 (translation elongation factor 1-alpha), rpb1 (DNA-directed RNA polymerase II largest subunit 1), rpb2 (second largest subunit of RNA polymerase II), and atp6 (adenosine triphosphate [ATP] synthase subunit 6). Comprehensive phylogenetic analyses revealed 20 Clitocybaceae species from our collections, which are distributed in four genera, i.e. Collybia, Lepista, Pseudolyophyllu.m, and Singerocybe. Combined with morphological characteristics, 13 of them were identified as known species and seven were described and illustrated as new species in this paper. These findings significantly contribute to our understanding of Clitocybaceae diversity and taxonomy in northern China.