Mycoscience最新文献

The mushroom Lentinula edodes, is consumed worldwide and has high industrial value because of its rich content of bioactive compounds such as ergothioneine and eritadenine. Currently, mainstream artificial cultivation methods for this mushroom typically use synthetic logs. However, browning of the stem’s interior (stem browning) has been observed during the cultivation in some L. edodes strains. Although browning does not affect the taste or other qualities of the mushroom, it gives consumers a perception of “poor quality”, and is a major challenge for producers. To identify the genes responsible for stem browning in this mushroom, we performed differential gene expression analysis during stem browning development and quantified it using real-time PCR. Our results indicated that certain oxidoreductases, such as tyrosinase and laccase, were significantly upregulated during the progression of stem browning. The results obtained in the present study provide valuable insights to address the problem of stem browning in mushroom L. edodes.

Aspergillus species take up various metal ions from environment. The morphology of Aspergillus oryzae strains can vary under the influence of various metal ions. Here, the effects of Ti⁴⁺, V³⁺, Sr²⁺, Ba²⁺, Al³⁺, Fe²⁺, Zn²⁺, Mn²⁺, Ca²⁺, and Cu²⁺ on morphological parameters of A. oryzae strains RIB40 and RIB143 were estimated. Colony diameter, conidiation, vesicle head size, and stipe width in both strains varied with concentration. Ti⁴⁺, Sr²⁺, Ba²⁺, Al³⁺, Fe²⁺, and Ca²⁺ affected conidiation in similar tendency between two strains. The effects of Ti⁴⁺, V³⁺, Sr²⁺, and Ba²⁺ on the morphology of A. oryzae are reported here for the first time. Induction of growth of both strains by 0.0001% Ti⁴⁺ may help the fermentation industry. Induction of conidiation in RIB40 by 0.001% Cu²⁺ confirmed previous results that low concentrations of Cu²⁺ promote the growth of Aspergillus. The most novel finding is that 0.001% Zn²⁺ increased the vesicle head size in RIB40; possible reasons are discussed.

A new species, Leucoagaricus karjaticus, was described from the tropical region of the Western Ghats of Maharashtra, India based on morphological characteristics and molecular phylogenetic analysis. Leucoagaricus karjaticus is characterised by its yellowish brown to reddish brown granular scales on the pileus, stipe apex exudes colourless drops, broadly ellipsoid to ellipsoid to ovoid basidiospores, clavate to cylindrical, catenulate cheilocystidia with subglobose to cylindrical ante-terminal elements. Further, the molecular markers nrITS and nrLSU sequence data analyses of Leucoagaricus karjaticus with their sister taxa revealed the distinct phylogenetic position of the new species.

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.