Mycoscience最新文献

Flowering of Henon bamboo (Phyllostachys nigra var. henonis) was observed in Japan in 2020s. We estimated that the observation of flowering was recorded for the first time in 120 y. Additionally, stromata of Aciculosporium take have also been observed in the flower buds, or spikelets, of Henon bamboo. Aciculosporium take usually forms stromata at the vegetative shoot apex, which presumably originated from ancestral pathogens affecting floral tissues. However, given the infrequent occurrence of bamboo flowering events, it is unclear whether A. take still retains the ability to colonize ovaries of flowers. To ascertain the location where the fungus forms stromata, anatomical and histological analyses were performed. Because flower buds, including floral organs, are fragile, tissue sections were prepared by adhering them to cellophane tape, and subsequently examined using a triple fluorescent staining method. The findings showed that the fungus did not invade the ovaries but formed stromata from the apical rudimentary floret within the flower buds.

The genus Metarhizium (Hypocreales: Clavicipitaceae) is mostly composed of entomopathogenic fungal species. Many of these species are anamorphic and difficult to distinguish morphologically. Furthermore, most isolates of this genus have a broad host range, making classification based on host-insect species uncertain. Molecular phylogenetic analysis based on DNA sequence information distinguishes these species well and revises the taxonomy of Metarhizium. However, in the revisions, the major groups within the genus, such as M. anisopliae complex, were classified regardless of their phenotypic differentiation. Therefore, the characteristics of the individual species remain unclear. To explore the species-specific characteristics of Metarhizium spp., the author performed a phylogenetic analysis and characterization of Metarhizium spp. in Japan. The results showed that strains of the M. brunneum and M. pemphigi clades exhibited cold-active growth characteristics and preferred forested environments over M. pingshaense. In the M. majus clade, a specialist of scarab beetles, isolates from different Scarabaeidae species, including the coconut rhinoceros beetle (Oryctes spp.) and flower chafer beetle (Protaetia orientalis), formed separate subclades and showed strong virulence against their original hosts. This review describes the current state of understanding of the taxonomy and species-specific characteristics of the genus Metarhizium, and includes the author’s own previous study.

In this study, white jelly mushrooms that were collected in Tottori Prefecture, Japan, were identified as Tremella yokohamensis by phylogenetic analysis of the rDNA-ITS region. Fluorescent microscopic analysis using 4’,6-diamidino-2-phenylindole staining to visualize the nuclei in each cell revealed that basidiospores isolated from the fruiting body were monokaryotic. Furthermore, monokaryotic yeasts were germinated from these basidiospores and the resulting crossed mycelium was dikaryotic and bore clamp cells, suggesting a heterothallic lifecycle for this species. Crossing between compatible yeast strains, such as TUFC 101924 and TUFC 101925, that were isolated from the same fruiting body, successfully induced development of the filamentous stage bearing clamp connections after 7 d of incubation on Kagome vegetable juice agar medium. Mating compatibility tests employing 15 basidiospore isolates revealed that this fungus possess a bipolar mating system. The results indicated that T. yokohamensis is a heterothallic and bipolar mushroom.

Fusichalara pallida sp. nov. is described from decaying wood submerged in a freshwater stream in Taiwan. The phylogenetic relationship of Fusichalara species was sought among representative taxa from related fungal lineages, namely the Chaetosphaeriales and Glomerellalles in the Sordariomycetes, and various other ordinal groups in the Eurotiomycetes, by comparing the concatenated ITS and LSU sequences of their nuc rDNA. The novel Fusichalara species from Taiwan clustered with F. minuta within the Sclerococcales besides other ordinal groups in the Eurotiomycetes. Morphologically, F. pallida is comparable with F. dimorphospora and F. novae-zelandiae in having long-cylindrical first-formed conidia and fusiform subsequent conidia with paler end cells, however, they differ in conidial dimensions. With the addition of this novel taxon, Fusichala now comprises seven species. A synopsis of these species and a composite illustration of their conidial morphology are given to ease identification.

Paulownia tree canker is a major disease of Paulowniae tomentosa in Japan. The pathogen was described as Valsa paulowniae in 1916 by Hemmi and Miyabe. However, its current taxonomic status and phylogenetic position are uncertain. In this study, we reviewed the protologue of this species and rediscovered the syntypes maintained at the Hokkaido University Museum (SAPA). From these specimens, a lectotype was selected. The molecular phylogenetic position of this species was examined with newly collected samples. Based on the result of phylogeny and morphology, an epitype of this species was designated and transferred to the genus Cytospora.

Tricholoma matsutake is an edible ectomycorrhizal mushroom that forms a symbiotic association with Pinaceae trees by constructing a large extraradical mycelial area (called a shiro) in the soil. The detection of this fungal mycelium in the soil is crucial for estimating the success of outplanted mycorrhizal seedlings inoculated with T. matsutake under experimental conditions. Although several T. matsutake-specific DNA markers have been reported for efficient detection in the field, no comparative study has been conducted to assess their effectiveness. In the present study, we targeted the nuclear ribosomal DNA intergenic spacer 2 (IGS2) region for the detection of T. matsutake. The newly designed TmSP-I-2F/TmSP-I-2R primer pair, which targets a partial IGS2 sequence (543 bp), effectively detected T. matsutake from pine root and soil samples via PCR assay, outperforming other T. matsutake-specific primers. In combination with a PCR system targeting LTR DNA markers that were previously developed, a PCR system with the TmSP-I-2F/TmSP-I-2R primer pair set can expedite investigations of the dynamics of T. matsutake genets in mycorrhizas and shiro.

Sake is a Japanese alcoholic beverage produced by fermenting steamed rice and koji (a culture of Aspergillus oryzae on steamed rice) with sake yeast, a strain of Saccharomyces cerevisiae. Sake yeast strains are important for maintaining product quality and process efficiency. In this study, a S. cerevisiae strain from Muramatsu Park, Gosen City, Niigata Prefecture was isolated using a loop-mediated isothermal amplification (LAMP) assay. The yeast strain was cultured using the mass spore-cell/cell-cell mating method with a sake yeast haploid. The resultant hybrid yeast strain, HG-3-F2, exhibited superior efficiency in alcoholic fermentation compared with the HG-3 strain. Our findings support the applicability of these original and mating strains in sake brewing.

Russula rubrosquamosa (Russulaceae, Russlales) is described as a novel species from Yunnan Province, southwestern China. It is morphologically recognised by a small basidiocarp with orange-yellow to orange-red scales on the pileus and stipe, white lamellae, orange-red to bright red basal mycelia, subglobose to broadly ellipsoid basidiospores with dense warts and short or long ridges. Phylogenetically analyses of DNA sequences from part of the 28S gene combined with the nuclear rDNA internal transcribed spacer (ITS) region also confirm that R. rubrosquamosa forms an independent lineage within Russula subgenus Heterophyllidia section Ingratae. A comprehensive description, color photographs of fresh basidiomata, line-drawings of microstructures and comparisons with morphologically similar species are provided in this paper.

Most Mucoromycota fungi form zygospores as sexual reproductive structures. When two colonies of compatible strains meet, zygospores are formed in the area where the colonies meet. The structure and development of zygospores have been studied for a long time by light microscopy and electron microscopy. This study is the first time-lapse report on the dynamic movements of sexual and asexual reproductive processes by live imaging in Gilbertella persicaria (Choanephoraceae, Mucorales). Our live imaging analysis indicated the formation of zygospores begin immediately after two aerial hyphae contact whether at the tip or middle of the hyphae. The early-stage zygospores elongated from the contact site with a rate of 1.2–1.7 μm/s and reach < 200 μm in 2–3 h. Following maturation of zygospores, from progametangia to gametangia and maturation stage, took a few hours, in total 5 to 6 h after the first contact of two hyphae. When a zygospore was formed near the tip of hypha in contact with the partner hypha, the hyphal growth ceased. When zygospore was formed behind the tip of the hypha, the hyphal growth continued without slowing down. This study provides quantitative spatio-temporal information on the dynamics of zygospore formation.