Trichoderma species are generally abundant on decaying wood and in soil because of their success in various heterotrophic interactions, including decomposition, parasitism, and even opportunistic endophytism. Many Trichoderma species or, precisely, many individual Trichoderma strains, have various important applications in industry and human life, which led to the inclusion of Hypocrea jecorina (Trichoderma reesei), the well-known producer of industrial enzymes, in the list of organisms whose genomes have been sequenced. Trichoderma species also have been adopted as agents of biological control of plant pathogenic fungi and as antibiotic producers. Trichoderma longibrachiatum is known as an opportunistic pathogen of immunocompromised mammals, including humans, and some species are common indoor contaminants. Given these properties, correct identification at the species level is highly desirable. However, within the past decade, the number of recognized Trichoderma species has tripled, reaching 100. Therefore, Trichoderma taxonomy and species identification is a difficult issue. The abundant homoplasy in phenetic characters is likely the reason, given that the number of morphologically distinct species is significantly lower than the number of phylogenetically distinct species recognized using methods of gene sequence analysis. In this review, we introduce to the scientific community the development of modern tools for Trichoderma species identification: the oligonucleotide barcode program TrichOKEY version 1.0, and TrichoBLAST, the multilocus database of vouchered sequences powered by a similarity search tool. We also discuss the application of the Genealogic Concordance Phylogenetic Species Recognition approach. In combination, these advances make it possible to identify all known Trichoderma species based on sequence analysis.

This review discusses DNA-based methods used for identification of yeasts. Nuclear DNA reassociation was the first quantitative molecular method employed for recognition of yeast species and has provided a baseline for interpretation of other molecular comparisons. Among these, gene sequencing is the most definitive method, with ribosomal RNA gene sequences providing the preponderance of available data. Multigene analyses that include the sequences of protein encoding genes are being increasingly developed to provide a more definitive resolution of species. A number of rapid identification methods, such as denaturing gradient gel electrophoresis (DGGE), temperature gradient gel electrophoresis (TGGE), and flow cytometry, which are based on species-specific gene sequences, are available for use in diagnostic laboratories.

To investigate the distribution of clubroot of a cruciferous weed, Cardamine flexuosa, caused by Plasmodiophora brassicae, field surveys were conducted in Hokkaido, Aomori, and Okinawa, and major isolated islands in Japan during 1993–2004. The disease was newly recorded in Aomori and nine islands in five different prefectures, including Sado (Niigata), Oki (Shimane), Mishima (Yamaguchi), Tsushima, Iki and Goto (Nagasaki), and Koshiki, Yakushima, and Tanegashima (Kagoshima). The diseased plants were not found in Hokkaido and Okinawa (islands of Okinawa, Kumejima, Ishigaki, Iriomote, and Kohama). However, inoculation tests showed that most C. flexuosa collected from Hokkaido and Okinawa included many susceptible plants. The result suggests that resistance of the plants is not the reason that the disease was not found in these areas.

We previously reported that MD-Fraction (Klasma-MD), a specific-structured β-glucan extracted from fruit bodies of maitake mushrooms (Grifola frondosa), can activate cellular immune systems and express antitumor effects. The molecular weight of the MD-Fraction ranged from 1200000 to 2000000. The molecular weight of the products of the MD-Fraction obtained after hydrolysis by endo-β-1,6-glucanase from Tricoderma harzianum was reduced to 250000 in terms of dextran, and these products inhibited MM-46 carcinoma in C3H/HeJ mice by 67.9% after intraperitoneal injection. In addition, interleukin-12 and interferon-γ values were increased 1.4 fold and 2.1 fold, respectively, compared with control values. From these results, low molecular weight MD-Fraction (L-MD-Fraction) maintains an immunological active site.

This study was carried out to elucidate the poorly understood processes of arthroconidiation through coremium formation using Pleurotus cystidiosus subsp. abalonus. The coremia exclusively produced dikaryotic arthroconidia with the remnant of a clamp connection. Cells in the subapical zone of the hyphal bundle reduced their length by division before arthroconidiation. Approximately 400000 arthroconidia were produced by a coremium in 1 day, with constant productivity over a 2-week period. Continuous cell extension and division in the coremium stipe supplied cells for arthroconidiation at the coremium apex, which is surrounded by a liquid droplet (coremioliquid). Maintenance of moisture with coremioliquid was necessary for arthroconidiation. The coremioliquid formation was performed by active liquid transportation in the hyphae, a process that was blocked by the microtubule depolymerization agent thiabendazole.

On the gill surfaces of agaric fruit bodies fed on by Collembola, the hymenium layer was consumed and many fecal pellets containing many basidiospores were observed. The hymenial area consumed by a collembolan (=Hypogatsrura denisana) varied from 1% to 92%, correlating with the density of collembolans on each fruit body among 11 agaric species. In Lactarius quietus, the hymenial area consumed by collembolans varied from 30% to 69% during the 5 days during which sampling took place. A weak correlation was found between the ratio of the hymenial area and the density of collembolans on the fruit bodies, and this fact suggested that other factors influenced the ratio of the hymenial area consumed by collembolans.

In this study, genetic variation of Armillaria mellea subsp. nipponica was estimated using intergenic spacer-restriction fragment length polymorphism (IGS-RFLP) and amplified fragment length polymorphism (AFLP) analyses. Four IGS-RFLP phenotypes were produced, of which two have never been reported. AFLP analysis suggested that the 11 isolates used could be divided into five subgroups, and the isolates within the same subgroup were distributed throughout a relatively large area in Japan. A parental isolate and its offspring (single-spore isolates) showed an almost identical AFLP profile to each other. These results suggest that the large distribution of the isolates within the same subgroup were established via the basidiospore from a common parental strain.

The entomopathogenic fungus Cordyceps militaris belongs to vegetable wasps and plant worms and is used as herbal medicine, but β-1,3-glucan biosynthesis has been poorly studied in C. militaris. The fungal FKS1 gene encodes an integral membrane protein that is the catalytic subunit of β-1,3-glucan synthase. Here, we isolated cDNA clones encoding a full-length open reading frame of C. militaris FKS1. Cordyceps militaris Fks1 protein is a 1981 amino acid protein that shows significant similarity with other fungal Fks proteins. This study is the first report of molecular cloning of the β-1,3-glucan synthase catalytic subunit gene from vegetable wasps and plant worms.

A strain of yeast isolated from insect frass collected in Thailand was found to represent a hitherto undescribed species of a basidiomycetous anamorphic genus Trichosporon. It is described as Trichosporon siamense. In the phylogenetic tree based on the D1/D2 region sequences of 26S rDNA, this yeast constitutes a cluster with several Q-9 having species of Trichosporon including T. otae and T. brassicae but is clearly differentiated from these species by 1.8% or more base substitutions. In the internal transcribed spacer region (ITS1 and ITS2), this species differs from T. scarabaeorum, the nearest species, by 6.5% base substitution.