Phytopythium is a recently established genus with sporangial morphology similar to Phytophthora and zoospore discharge similar to Pythium. It contains 27 officially recognized species including plant pathogens as well as aquatic saprophytes. Among the most widely distributed are P. helicoides and P. vexans, followed by P. oedochilum and P. litorale, each having been reported on six continents. This study uses morphological and molecular analyses to describe two novel Phytopythium species: P. phamii from river water in Vietnam and P. virginianum from an irrigation pond in the USA and citrus orchard soil in Vietnam. Based on the maximum likelihood and Bayesian phylogenies, P. virginianum and P. phamii generally grouped with members of the Phytopythium clade 2, near P. chamaehyphon and P. helicoides. Isolates of both species grew at temperatures between 7 and 35 C, with an optimum temperature of 30 C for P. phamii and 35 C for P. virginianum. Although abundant oospore production was observed in cultures of P. phamii, none was observed in cultures of P. virginianum on any of the media used. The formal description of these new species helps scientists and regulators understand the geographic distributions of organisms and identify potential emerging pathogens that can become a threat to agricultural crops.

The environment in which a fungus grows directly influences fungal traits such as development, transmission, and pathogenic potential. The environmental niche encompasses factors such as nutrient availability, biotic and abiotic stressors, as well as host-derived chemical cues. In fungal pathogens, where conidia act as the infectious agents, the environmental niche impacts the quantity and quality of the produced conidia, thereby affecting the ability of conidia to infect and kill hosts. In the present study, we investigated the effect of host-derived medium types on various phenotypes, including fungal growth rate, conidial production, and virulence in two entomopathogenic fungi, Metarhizium acridum and Metarhizium brunneum. Three medium types derived from insect material were compared with a standard laboratory medium. When grown on insect-derived medium, cultures exhibited enhanced conidiogenesis and reduced time to conidiogenesis. Although the conidia produced on this host-derived medium germinated and grew at rates comparable to those generated on control medium, they demonstrated higher virulence in one isolate of M. brunneum. These results highlight that the composition of growth substrates can regulate fungal reproductive strategies and virulence, with implications for developing high-throughput phenotyping and for the optimization of mass production and efficacy of entomopathogenic fungi in biological control applications.

The genus Parasola is known for its diverse range of species, but the taxonomic understanding of its diversity in southern Punjab, Pakistan, remains incomplete. In this study, we describe three novel species of Parasola from this region, identified using an integrative approach combining morphological examination and molecular phylogeny. We included field pictures of the species in their natural habitats and illustrations of the microscopic features to complement the taxonomic descriptions. Molecular phylogeny, based on internal transcribed spacer (ITS) and 28S sequences, revealed that two species, P. pakistanica and P. fragilissima, nested within P. sect. Conopileae, whereas P. brunneodisca nested within P. sect. Parasola. These results strongly support the distinctiveness of these taxa, separate from previously described species. Our study contributes to expanding the known diversity of Parasola in southern Punjab, offering novel insights into its taxonomy and the evolutionary relationships among species within the genus. These findings highlight the importance of combining multiple approaches to taxonomic studies in uncovering hidden biodiversity.

Recent advances in fungal genome sequencing have dramatically altered our understanding of the phylogeny and evolution of Fungi. However, there are still many poorly studied obligate parasitic or symbiotic fungi for which we lack any genomic information or knowledge of where they fit in the fungal phylogeny. Ancylistes, an endoparasite of desmid green algae, is such an understudied fungal genus that is classified among Entomophthoromycotina in Zoopagomycota on the basis of morphology. However, this relationship is perplexing, because Zoopagomycota is almost entirely composed of animal-associated fungi. In this study, we found and cultivated Ancylistes closterii with its green algal host Closterium sp. and sequenced its genome to investigate its phylogenetic position and evolution. Phylogenetic analyses using rDNA and genome-scale data sets showed that A. closterii was sister to other Entomophthoromycotina fungi, confirming the taxonomic position of Ancylistes. Despite the ecological distinctiveness between Ancylistes and other Entomophthoromycotina fungi, our comparative genomic analyses revealed shared traits of these fungi such as lineage-specific subtilases and hybrid histidine kinases. Ancylistes also possessed unique genes among Zoopagomycota fungi such as plant cell wall-degrading enzymes that could be important for infection of algae.

Fungi in Alternaria sections Infectoriae and Pseudoalternaria are commonly associated with commercially important crops, yet their biosystematics remains difficult to resolve because standard molecular markers often lack sufficient phylogenetic resolution. In this study, we used candidate loci identified in previous phylogenomic analyses to develop four new molecular markers (SIP-03, SIP-04, SIP-06, and SIP-08) that were specifically designed to be highly informative for these two sections. The performance of these new markers was evaluated using 237 strains collected primarily from wheat in Canada and tomatoes in the Baltic states, representing the largest data set analyzed to date. The four markers showed high amplification success and contained strong phylogenetic signal. Combined phylogenetic analyses recovered all of the previously recognized lineages within sections Infectoriae (Inf1, Inf3, Inf3) and Pseudoalternaria (Pse1, Pse2) and revealed a novel lineage, designated Inf4, associated with wheat in western Canada. Concordance of lineage assignment was high, with 94.1% of strains being placed consistently across all four markers and an overall marker conflict frequency of less than 3%. Our expanded sampling identified some lineage-specific patterns in regard to host association and geographic distribution. For example, the Inf1 lineage showed high molecular diversity and was dominant among tomato-associated strains from Baltic Europe, whereas Inf2 and Pse2 were the primary lineages infecting western Canadian wheat. Our study provides robust new tools for identification and classification of taxa within sections Infectoriae and Pseudoalternaria, refines their phylogenetic framework, and facilitates future studies on the pathology, epidemiology, and mycotoxin production of these agriculturally important fungi.

Pseudomitrula (Leotiomycetes, Helotiales) is a genus of minute earth tongues. Pseudomitrula horakii, the only described species in the genus, is recognized by cylindrical to spathulate apothecia. It was originally placed within Geoglossaceae but is currently classified within Helotiales, as genus incertae sedis, or within either Cenangiaceae or Helotiaceae. Through recent expeditions to southern South America, dozens of collections of Pseudomitrula were made. Based on the phylogenetic reconstruction of an internal transcribed spacer (ITS) data set, we identified eight distinct groups among our collections, representing P. horakii and seven putative species, three of which are formally described here: P. gamundiae, P. mapuche, and P. variabilis. We present morphological descriptions and illustrations for all four named species. To resolve the placement of Pseudomitrula within Helotiales, we included newly generated Pseudomitrula sequences in a 15-locus class-wide data set. The resulting phylogeny showed that Pseudomitrula species form an independent clade sister to five families in Helotiales: Helotiaceae, Lachnaceae, Pleuroascaceae, Solenopeziaceae, and Tricladiaceae. Morphologically, Pseudomitrula has little in common with taxa in these families that either form sessile or stalked cup- or cushion-shaped apothecia or cleistothecia or produce aquatic hyphomycetous or microscopically small asexual morphotypes. For these reasons, we propose the new family Pseudomitrulaceae within Helotiales. This study expands the knowledge of southern South American diversity of Leotiomycetes.

Epipactis helleborine is an orchid species that has been introduced to North America and continues to expand its range. Numerous studies have investigated the mycorrhizal specificity of these orchids in their native range and found broad associations with Ascomycota, particularly Wilcoxina. Similar studies in North America are rare. We assessed the fungal diversity associated with populations of E. helleborine, and the surrounding soil, in mixed habitats on Vancouver Island (Canada) to make comparisons with findings from the species native range. After collecting 45 rhizomes and 36 soil samples, we amplified the nuclear ribosomal internal transcribed spacer (ITS2) region to assess alpha and beta diversity. BLAST searches were conducted, and phylogenetic reconstructions of high-matching fungal sequences from other E. helleborine studies were created. We demonstrate that E. helleborine populations continue to associate with a diverse group of Ascomycota fungi, particularly Wilcoxina spp. as they continue to expand their range northward in western North America. However, we also detected a novel association among E. helleborine rhizomes and Rhexocercosporidium, a genus containing known saprophytes and plant pathogens. Our results indicate that this orchid can pair with an extensive range of fungal partners, likely by taking advantage of varying degrees of phylogenetic niche conservatism among different fungal groups, which could have wide-reaching implications in terms of further geographic expansion and introductions to new continents.

In this study, we describe two new species of Cortinarius subgen. Telamonia sect. Firmiores: Cortinarius curiosus and C. ferrugineochraceus. Both species are well supported by phylogenetic analyses and are characterized by distinct morphological features. Cortinarius curiosus is resolved within the broader /Alboviolacei clade, forming a strongly supported lineage together with the three European taxa and C. obliquus from USA. Morphologically, C. curiosus can be distinguished from the European C. acutispissipes, C. alboviolaceus, and C. paralbocyaneus by first its silvery-whitish pileus and the strongly ornamented spores. Moreover, differentiation of all these four species of the clade based on spore size and ornamentation has been established as far as possible. In Europe, C. curiosus is associated with evergreen oaks, in the USA with Quercus nigra, which can be called partially evergreen. In addition, these four species are compared with the North American Cortinarius obliquus. The second new species, Cortinarius ferrugineochraceus, is placed within the /Turgidoides clade, where it forms a distinct lineage closely related to, but clearly separable from, C. turgidoides. These two taxa are compared in detail with respect to morphology, molecular characters, and ecological preferences. Cortinarius ferrugineochraceus can easily be recognized by its white, frosty veil covering pileus and the ochraceous orange to ferrugineous colors when young. In contrast, the veil of C. turgidoides is clearly fibrillose and more distinct and the pileus is more leather-brown to ferrugineous colored. Furthermore, the taxonomic status and previously proposed synonyms of C. turgidoides are critically reassessed in light of the phylogenetic evidence presented here.

Red leaf blotch, caused by Coniothyrium glycines, is a major leaf spot disease of soybean in Africa. Because of its unique morphological characteristics, C. glycines has been placed in numerous genera since its description in 1957, and recent phylogenetic evidence has suggested that its current placement within Coniothyrium is incorrect. To provide nomenclatural stability, we reevaluated its evolutionary history and taxonomy using a phylogenomic approach. We produced draft genomes for 13 close relatives of C. glycines and generated a consensus tree from 4643 BUSCO genes in these species and related Dothideomycetes. We show that Coniothyrium is not monophyletic and C. glycines is closely related to Aristastoma oeconomicum, a once prevalent leaf spot pathogen of cowpea in the eastern United States. Similarities in morphology and disease symptomology, along with genome distance estimations and a phylogeny based on internal transcribed spacer (ITS) and partial nuclear 28S rDNA (D1-D2) data, support the transfer of C. glycines and another species, Coniothyrium dolichi, to Aristastoma. The inclusion of this species in Aristastoma expands the morphological concept of this genus to include species that produce sclerotia and have aseptate conidia. The improved systematics and genomic resources generated with this study will advance the development of diagnostics and detection assays of this high-consequence plant pathogen.

Several species of mushroom-forming fungi have been reported to trap and consume nematodes. Nematophagy is hypothesized to have evolved as a mechanism for supplementing nitrogen, analogous to carnivorous plants. In this study, we systematically reviewed all the putative nematode-trapping saprotrophic Agaricales and documented their behavior in the presence of nematodes. Hohenbuehelia mastrucata, Pleurotus citrinopileatus, and P. djamor all trapped and consumed nematodes, as reported previously. In contrast, we found that Stropharia rugosoannulata and Coprinus comatus produce structures that have been suggested to function in nematode trapping, but these fungi neither trap nor consume the nematodes. It is possible that the structures interpreted to function in nematode trapping in S. rugosoannulata and C. comatus act as defensive mechanisms against fungivory.

Six new species of Inocybaceae from North America are described as new. Most are common and widespread throughout eastern North America. Phylogenetic analyses of nuc rDNA ITS1-5.8S-ITS2 (ITS), harnessing numerous community science records, together with nuc 28S rDNA support the phylogenetic distinctiveness of each species with strong support values. Sequences of additional genetic loci, including RNA polymerase II largest subunit (rpb1) and second largest subunit (rpb2), were also produced to supplement the descriptions and strengthen future phylogenetic studies. Of these new taxa, three are described in Inocybe: I. albofusca, a smooth-spored species in the Flocculosa clade; I. communis, a nodulose-spored species in the Xanthomelas clade; and I. lincoffii, a nodulose-spored species in I. subsect. Napipedinae. Inosperma aureiavis is a member of the Maculatum clade, whereas Pseudosperma aurivetum is a member of the Umbrinellum clade. Mallocybe diabolica is a narrow-range endemic known only from southeastern Arizona and Mexico and is allied with the Heimii clade. Complete descriptions and illustrations are presented for each species.

The chytrid Synchytrium endobioticum causes potato wart disease and is a regulated quarantine pathogen. Due to its obligate association with the potato host, obtaining pure genome sequences has been technically challenging. Previous population studies were limited to microsatellites or mitochondrial genomes, which capture only a small portion of the pathogen's genetic diversity. To enable the first population genomic analyses of the nuclear genome of S. endobioticum, we designed and applied a robust single-nucleotide polymorphism (SNP) discovery strategy to existing and novel sequence data sets that represent the global diversity in potato production systems. We demonstrate that reliable nuclear genome data can be recovered from contaminated environmental samples, where S. endobioticum constitutes only ~5% of total reads. After stringent filtering, 74 high‑quality data sets for isolates from 10 countries and 12 pathotypes were retained. Phylogenetic analyses of genome-wide SNP alignments, some with up to 188 817 SNPs, identified three well-supported nuclear phylogroups that largely corresponded to mitochondrial haplogroups: (i) a basal Peruvian clade; (ii) a European/Canadian clade containing mostly pathotypes 1(D1), 2(G1), 6(O1), and 8(F1); and (iii) a clade with pathotypes 18(T1) and 38(Nevşehir). Using a subset of 13 327 homozygous SNPs, population structure analysis and phylogenetic networks confirmed three genetic clusters with limited admixture. Our analyses indicate that potato wart was introduced into Canada from a European source. Pathotype designations do not correspond to exclusive monophyletic lineages. Analysis of the AvrSen1 effector revealed that distinct loss-of-function variants can occur in multiple nuclear phylogroups, suggesting independent emergence of some virulence phenotypes. Isolates contain a reservoir of genetic variation, which may allow adaptation to changing host resistance pressures. This nuclear genome approach provides significantly greater resolution than previous molecular markers used for strain tracking. Furthermore, the solid phylogenetic framework developed here will support future effector-based pathotype inference and will aid regulators in surveillance and quarantine decisions for this high-risk pathogen.

Based on a study of sporocarps developed in moist chamber cultures on the bark of Dacrydium elatum collected in Kon Chu Rang Reserve, central Vietnam, we describe a new species, Licea gorgona (Myxomycetes, Liceales). The new species is morphologically distinct from other species of the genus Licea due to its well-developed capillitium threads connected to the peridial margins, minute sporocarps with dark brown spore mass, circumscissile dehiscence via preformed ridges, and spores with ephemeral, rounded warts that detach readily, creating irregularly smooth ("bald") patches. Apart from the morphological study, partial sequences of the nuclear ribosome small subunit 18S rRNA gene (18S nuc rDNA), mitochondrial cytochrome c oxidase subunit I gene (cox1), mitochondrial small subunit ribosomal gene (17S mt rDNA), and elongation factor-1 alpha gene (EF1α) were also provided. A multigene phylogenetic analysis places L. gorgona within the Lucisporomycetidae clade with other Licea species. We interpret capillitium in L. gorgona as plesiomorphic retention, contrasting with its apomorphic reduction in most other Licea species. Consequently, we propose revising the taxonomic diagnoses of the order Liceales and family Liceaceae to explicitly encompass species with a well-developed capillitium. However, due to the absence of molecular data for Listerella paradoxa and the majority of described Licea species, coupled with unconfirmed plasmodium morphology in L. paradoxa, we defer formal conclusions on the taxonomic status of Listerella and a comprehensive revision of the Licea circumscription.

In 2023, conifers with Rosellinia infections were discovered in Maine, New Hampshire, and Ohio. The trees displayed twig and needle blight with dense mats of mycelium. The isolates causing the infections were provisionally identified as Rosellinia mycophila or R. herpotrichoides according to current morphology-based criteria. Both species belong to the R. thelena subgroup (subg. Corrugata) of Rosellinia as defined by Petrini (2013, Bibliotheca Mycologica 205). To date, no molecular data are available for species within this subgenus. To address this gap, we sequenced several loci and conducted a multilocus phylogenetic analysis (nuc ITS1-5.8S-ITS2 rDNA [ITS], nuc 28S rDNA D1-D2 [28S] regions, β-tubulin [TUB2], and the second-largest subunit of the DNA-directed RNA polymerase II [RPB2]). Recently, several Rosellinia species were segregated to Dematophora because they group in a separate clade and form distinct asexual morphs: Rosellinia species form Geniculosporium-like asexual states, whereas Dematophora species form Dematophora-like asexual states. Our analysis shows that R. mycophila and R. herpotrichoides form a well‑supported clade adjacent to these groups and share Nodulisporium-like anamorphs. The specimens collected in this study exhibited more than 99.3% sequence similarity. In 1961, Petrak (Sydowia 15:242-246) considered a specimen later identified as R. mycophila to be a form of R. herpotrichoides with small ascospores. In 1986, Francis (Trans Br Mycol Soc 87:397-400) disagreed and argued that the two should be maintained as separate species. Our molecular data suggest limited genetic distinction between these species; however, we do not formally synonymize the taxa. Broader sampling, especially from European and type-associated material, will be needed to evaluate whether morphological features reliably delimit R. mycophila and R. herpotrichoides.

Members of the phylum Neocallimastigomycota, often referred to as anaerobic gut fungi (AGF), primarily inhabit the gut of herbivorous animals. To date, 25 AGF genera have been described, but only five harbor more than one species. Here, we report on the isolation and characterization of novel AGF isolates from the feces of a Boer goat. The isolates formed small, mostly round, dense colonies on agar roll tubes and produced flaky, loosely clumped white biomass in liquid medium. Microscopic features included monoflagellated spherical zoospores and monocentric filamentous thallus. Sporangia were spherical or ovoid, although elongated and oddly shaped sporangia were also observed. Zoospore release was observed through ruptures in the sporangial wall. Phylogenetic analysis using the ribosomal internal transcribed spacer 1 (ITS1) and the 28S nuc rDNA D1-D2 region (28S) showed the isolates to be most closely related to Joblinomyces apicalis, the only described species in the genus Joblinomyces (0.00-1.30% divergence in ITS1, 2.50-3.82% in 28S). Transcriptomic sequencing and subsequent analysis of the RPB1 (largest subunit of RNA polymerase II) region and average amino acid identity (AAI) value comparison clearly showed a high level of AAI sequence divergence (70.11-75.40%, average 72.53 ± 1.43%) when compared with all other genera within the order Neocallimastigales. Based on morphological and phylogenetic analyses, we propose to accommodate these isolates as a novel species within the genus Joblinomyces and propose the name of Joblinomyces undulatus. The type strain for this species is JC3.3.