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.

Novel Spencermartinsiella strains, JCM 35526^T and 261-2C, were isolated from biofilm formed on a reverse osmosis membrane in the phosphate recovery system of a semiconductor factory. Morphological, biochemical, physiological, and chemotaxonomic analyses as well as sequence analysis of the concatenated internal transcribed spacer region and D1/D2 domains of the large subunit of the rRNA gene confirmed that strains JCM 35526^T and 261-2C, were distinct from all currently known Spencermartinsiella species. The holotype and isotype strains of the new species, which is named Spencermartinsiella japonica, are JCM 35526^T and MUCL 58310^I, respectively.

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.

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.

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.