Mycologia最新文献

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.

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.

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.

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.

Lasius fuliginosus, a fungus-growing ant species distributed across Europe, hosts various fungi inside its carton nests in trees, including the nest fungus SP1 of the order Chaetothyriales, as well as the nest fungi SP5 and SP4 of the order Venturiales. The goal of this study was to gain a better understanding of the fungal interactions inside the L. fuliginosus nests as well as of potential interactions around the nests, including the effects of Armillaria mellea-a root-rot fungus infecting potential host trees. We performed two types of confrontation experiments on Petri dishes between the isolated nest fungi and A. mellea. Firstly, using de Wit experiments, we tested the fungal species in pairwise combinations at three different initial confrontation concentrations. Secondly, a linear confrontation setup focused on differences in directional growth of the fungal species in pairwise combinations as well as on the development of A. mellea rhizomorphs. For the fungi SP1, SP5, and SP4, we found positive influences on each other (SP1 on SP5, SP4 on SP1 and SP5, and SP5 on SP1) alongside no influence (SP1 on SP4, SP5 on SP4). SP1 had a significantly negative impact on the surface growth and directional growth of A. mellea, and SP5 triggered the strongest rhizomorph development of A. mellea, possibly a stress reaction of the root-rot fungus. Armillaria mellea did not negatively impact any of the nest fungi and even promoted the surface growth of SP1. The de Wit setup and the linear setup turned out to be complementary and together facilitated first insights into potential roles of the nest fungi in this association of ants and fungi in trees. Follow-up studies will need to assess how these findings under Petri dish conditions transfer to conditions in natural habitat, in the presence of both the ant and the tree host.

Diaporthe species are frequently reported as endophytes on mangroves. These species are also known pathogens affecting several important hosts worldwide, but have yet to be explored as pathogens in mangrove environments. In this study, symptomatic leaves and stems of several mangrove species were collected from mangrove forests and estuaries in Thailand. Forty-five Diaporthe strains were isolated from symptomatic leaves and stems of various mangrove species, associated with leaf spots and stem cankers, respectively. A polyphasic identification approach, comprising morphological, multilocus phylogenetic analyses (ITS, TEF1-α, TUB2, CAL, and HIS3), and pairwise homoplasy index tests, identified two new species complexes, 10 Diaporthe species belonging to three sections (Eres, Foeniculina, and Sojae). This included D. mayteni species complex, D. tanakae species complex, three novel species: Diaporthe mangroviorum, D. narathiwatensis, and D. rhizophoracearum, as well as 19 new host-pathogen associations for D. arecae, D. azadirachtae, D. biconispora, D. charlesworthii, D. siamensis, D. ueckeri, and D. vitimegaspora, and two new geographic records for D. azadirachtae and D. charlesworthii. Pathogenicity was confirmed on their original mangrove hosts using detached leaf assays, showing varying levels of pathogenicity. We also present evidence supporting synonymizing of D. eleutharrhenae, D. pseudobauhiniae, D. xishuangbannaensis, and D. yunnanensis with D. vitimegaspora. Furthermore, the taxonomic placement and identity of previously reported mangrove endophytic Diaporthe species have been updated. Based on this and previous studies, a total of 93 strains belonging to 16 Diaporthe species are associated with mangrove species. The findings of this study gave us a more holistic understanding of the Diaporthe species associated with mangroves, their lifestyles, etiology, and host range.

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.

The taxonomy of chalara-like anamorphs in Leotiomycetes was recently thoroughly redefined. Due to the morphological simplicity of these species, emphasis was given on monophyletic generic concepts defined based on rDNA. In our follow-up study, we revised the taxonomic classification of selected chalara-like fungi in the families Hamatocanthoscyphaceae and Pezizellaceae. We examined our isolates of chalara-like anamorphs and collections of discomycete teleomorphs from coniferous litter in Europe, along with a revision of related fungarium collections. We performed phylogenetic analyses based on data sets consisting of the internal transcribed spacer region ITS1-5.8S-ITS2, partial 28S nuc rDNA, and fragments of genes encoding either translation elongation factor 1α or RNA polymerase II second largest subunit. Our phylogenetic analyses showed that the inclusion of teleomorphs is essential for proper naming of the holomorphic species. In Hamatocanthoscyphaceae, we propose to synonymize the monotypic genus Chalarodendron with the recently erected genus Stipitochalara. Further, we provide evidence of Infundichalara microchona being the anamorph of Ciliolarina ligniseda. The anamorph for Hamatocanthoscypha laricionis, the type species of Hamatocanthoscypha, is also documented. Several sequences obtained from collections identified as H. laricionis were distantly placed in the phylogeny, indicating that a thorough revision of the genus is needed and its relationship with Constrictochalara and Xenochalara should be explored. In Pezizellaceae, we reveal the anamorph-teleomorph connection between Calycina (=Chalara) fungorum and Calycina subtilis and propose to synonymize Nagrajchalara angustata with N. inflatipes. Calycina (=Chalara) brevispora should be excluded from Leotiomycetes; molecular data from a recently obtained isolate showed that this fungus should be placed in Chalarina (Chaetosphaericaceae, Chaetosphaeriales, Sordariomycetes).

During a survey of fungi associated with Cyperaceae plants in northern and northwestern Iran, three previously undescribed species belonging to Alternaria section Nimbya were identified and characterized. These new species, namely, Alternaria azarbaijanica, A. caspica, and A. eleocharidis, spp. nov. were examined using a combination of morphological traits, cultural features, and molecular data. Remarkably, all three species produced both sexual and asexual morphs under laboratory conditions, providing rare insights into reproductive modes within Alternaria, where sexual morphs are rarely observed. Phylogenetic analyses based on five gene regions (ITS-rDNA, GAPDH, TEF1, RPB2, and Alt a 1) clarified their evolutionary relationships and supported species delimitation. Phylogenetic trees constructed using maximum likelihood, maximum parsimony, and Bayesian inference consistently resolved each species as a distinct monophyletic lineage within Alternaria section Nimbya. These findings reveal previously unrecognized Alternaria diversity on Cyperaceae hosts and underscore the value of combining morphological observations with multilocus phylogenetic approaches to resolve taxonomic complexities in Alternaria.