Orchid mycorrhizal (OM) fungi are essential for seed germination and seedling development in orchids. Although research on the molecular mechanisms underlying orchids–OM fungi interactions is progressing, detailed analyses, including fungal genomics, are limited. In this study, we performed short-read genome sequencing of two Tulasnella isolates obtained from the terrestrial orchid Cypripedium macranthos var. rebunense—both capable of inducing seed germination. Using sequencing data, we assembled genomes and predicted gene sets, each demonstrating over 95% completeness based on Benchmarking Universal Single-Copy Orthologs analysis, indicating high-quality assemblies and annotations. Phylogenetic analysis incorporating existing Tulasnella genome data revealed that these isolates belonged to Group IV, an early-diverging lineage distant from the other Tulasnella groups. Comparative genomic analyses demonstrated that Group IV Tulasnella possessed a distinct repertoire of genes encoding carbohydrate-active enzymes and lineage-specific small secreted proteins. Our results indicate that these genes are possibly involved in establishing symbiosis with Cypripedium species. These findings offer novel insights into the molecular basis of orchid–mycorrhizal interactions.

A new species of dothideomycetous sooty mould, Capnofrasera abieticola, is illustrated and described based on fresh specimens collected in Sugadaira, central Japan. It occurred mixed with the subicula of another dominant sooty mould, Metacapnodium neesii (Metacapnodiaceae), on the living twigs and leaves of Abies veitchii (Pinaceae, Pinales). It is morphologically distinguishable from the closest species Capnofrasera flatbergii on branches of Ulmus sp. (Ulmaceae, Rosales) in Sweden by its shorter and narrower phragmoconidia and its host preference. A single phragmoconidium was successfully isolated from the holotype (TNS F-108821) and yield a sterile culture (i.e., no fructifications). Molecular phylogeny based on the concatenated SSU, LSU, and RPB2 dataset revealed that C. abieticola could be assigned to Neoantennariellaceae, not Antennulariellaceae within Capnodiales s. str. (Dothideomycetes).

Resupinatus merulioides was originally described from Nikko, Tochigi Prefecture, Japan and characterized by its merulioid hymenophore. Since its description, no additional records have been reported from the type locality, and only a few records have been documented from other regions in Japan. Here, we report some new rediscoveries of R. merulioides from its type locality and other regions in Japan. Newly collected specimens were morphologically consistent with the original description. However, some fruiting bodies had different morphological characteristics such as variations in coloration. Molecular phylogenetic analyses revealed that Japanese specimens identified as R. merulioides formed a well-supported clade, and distinct from other species in this genus. Additionally, specimens labeled as R. merulioides from New Zealand formed a sister clade to R. merulioides s.s. and were genetically distinct. Because of newly observed morphological characters and DNA data, we designate an epitype based on the newly collected specimen from its type locality.

The genus Tulasnella is generally regarded as saprotrophic, but several species are known to form mycorrhizal associations. Basidioma morphology is a crucial taxonomic character in Tulasnella; however, recent studies have focused on DNA sequences of cultured mycelia isolated from orchid roots for species delimitation and description. In this study, we collected 16 Tulasnella basidioma specimens in western Japan and conducted a taxonomic study based on their morphology, culture properties, and molecular phylogenetic analyses. Phylogenetic analyses of the internal transcribed spacer (ITS) region resolved the specimens into six clades: Tulasnella sp. 1 (T. eichleriana), Tulasnella sp. 4 (a new species described here as T. nematospora), Tulasnella sp. 5 (T. albida), and three unidentified species (Tulasnella spp. 2, 3, and 6). Tulasnella nematospora is described here as a new species based on its thread-like basidiospores, monilioid hyphae forming chains of 2‒7 cells on PDA, and multinucleate hyphae. This study provides the first records of T. eichleriana and T. albida from Japan. The close phylogenetic relationship between Tulasnella sp. 6 and an orchid mycorrhizal Tulasnella lineage suggests symbiotic potential in this species, whereas the remaining taxa are presumed to be saprotrophic.

The family Clavicipitaceae (Hypocreales, Ascomycota) includes a wide range of fungal lifestyles and ecological interactions, but the phylogenetic relationships and evolutionary origins of its plant-parasitic taxa have remained controversial. To establish a robust, phylogenetically consistent classification, molecular phylogenetic, fossil-calibrated divergence-time, and likelihood-based ancestral state reconstruction analyses were performed using a multi-locus nuclear dataset. These analyses identified two deeply divergent, monophyletic clades of plant parasites: designated as Clavicipitoideae, comprising Aciculosporium, Balansia, Claviceps, and Epichloë; and Commelinaceomycetoideae, comprising Ustilaginoidea and Commelinaceomyces. Ancestral state reconstruction suggests that plant parasitism evolved independently at least twice within the family. In Clavicipitoideae, plant parasitism most likely originated directly from an invertebrate-associated ancestor, whereas in Commelinaceomycetoideae, it appears to have evolved through a transitional state involving root endophytism coupled with invertebrate parasitism. Divergence-time estimates place the origins of both lineages in the mid-to-late Cretaceous, concurrent with the early diversification of their monocot hosts. On the basis of these evolutionary inferences, major taxonomic revisions are proposed, including the establishment of a new subfamily Commelinaceomycetoideae, a new tribe Commelinaceomyceteae, an emended circumscription of the subfamily Clavicipitoideae, and the validations of the tribes Balansieae, Clavicipiteae, and Ustilaginoideae.

Microscope slide preparations made for the observation of the mycorrhiza of the mycoheterotrophic orchid Gastrodia elata were rediscovered and confirmed to be the original materials used by Shunsuke Kusano for his 1911 publication. In this study, we re-examined these historical slides to assess their preservation and scientific significance. Among the 115 slides, 61 clearly displayed the mycorrhiza of G. elata. Intracellular organelles closely resembling the ‘vesicle’, ‘globule’, ‘tubular sheath’, ‘globular bodies’, and ‘lignified papillae’ described by Kusano were observed, and staining reactions consistent with Heidenhain’s iron haematoxylin and Flemming’s triple stain remained visible in many specimens despite being more than a century old. Slides also contained tubers of Solanum tuberosum infected with mycelial strands of Armillaria mellea sensu lato, reflecting Kusano’s comparative approach to symbiosis and pathogenicity.

We identified a putative β-1,3-glucanase gene (GlGH128A) classified into the glycoside hydrolase family (GH) 128 from Ganoderma lucidum. This gene consists of a total length of 816 bp including the start and stop codon, and encode 271 amino acids, including a 22-residue signal peptide. The predicted mature protein has a molecular mass of 27.5 kDa and an isoelectric point of 5.82. Amino acid sequence comparison between GlGH128A and GH-128 β-1,3-glucanase from Lentinula edodes (LeGLU1), and homology model of GlGH128A based on LeGLU1 crystal structure exhibits TIM barrel fold with conserved two catalytic glutamic acid residues, and suggested two disulfide bonds of GlGH128A. Expression analysis showed that GlGH128A is expressed at higher levels in the fruiting body after harvest across multiple strains. These findings suggest that GlGH128A contributes to the autolysis of G. lucidum fruiting bodies.

Hydrophobins are low-molecular-weight amphiphilic proteins found in filamentous fungi. In this study, we focused on two Aspergillus oryzae hydrophobins, whose biological functions were unclear. We found that hydrophobins RolA and HypB are highly expressed. We created strains with disruption of one of the respective genes, ΔrolA and ΔhypB, and examined their phenotypes under various stress conditions. The two strains had different phenotypes under stress conditions that affected the cell wall surface function. Self-assembled structures on the conidial surface were absent in the ΔrolA strain, whereas specific structures on the surface of aerial hyphae were absent in the ΔhypB strain. Colony hydrophobicity was lower in the ΔhypB strain than in the control CNT strain, whereas conidial surface hydrophobicity was lower in the ΔrolA strain than in the control CNT strain. These findings indicate that RolA and HypB share similar functions on the cell surface, but RolA functions mainly on the conidial surface, whereas HypB functions mainly on the surface of aerial hyphae.