Helotiales is one of the most diverse groups of apothecial ascomycetes, including 3000—4000 taxa. Recent progress in the systematics, ecology, and their applications through research is herein reviewed based on the experiences of the author with a special emphasis on activities in Japan. In the past 30 y, more than 50 helotialean taxa have been added to the mycobiota of Japan, including new taxa. With the advent of molecular phylogeny, some families have been revisited, such as members with stroma (Sclerotiniaceae and Rutstroemiaceae) or hairs (Hyaloscyphaceae and Lachnaceae). Although the monophyly of Helotiales has not yet been demonstrated, our understanding of its phylogeny has greatly advanced. The unexpected ecological nature represented by endophytism has been revealed through barcoding and other molecular techniques. The research history of ash dieback is also reviewed, and the endophytism/saprophytism of the pathogen on its original host is discussed. Drug discoveries within Helotiales are reviewed, and successful examples are presented. As future perspectives, both the cumulation of occurrence and sequence data of Helotiales is greatly encouraged to elucidate this important group of fungi.
The cultivation of edible mycorrhizal fungi (EMF) has made great progress since the first cultivation of Tuber melanosporum in 1977 but remains in its infancy. Five cultivation steps are required: (1) mycorrhizal synthesis, (2) mycorrhiza development and acclimation, (3) out-planting of mycorrhizal seedlings, (4) onset of fructification, and (5) performing tree orchards. We provide examples of successes and challenges associated with each step, including fruiting of the prestigious chanterelles in Japan recently. We highlight the challenges in establishing performing tree orchards. We report on the monitoring of two orchards established between Lactarius deliciosus (saffron milk cap) and pines in New Zealand. Saffron milk caps yields reached 0.4 and 1100 kg/ha under Pinus radiata and P. sylvestris 6 and 9 y after planting, respectively. Canopy closure began under P. radiata 7 y after planting, followed by a drastic reduction of yields, while P. sylvestris yields still hovered at 690 to 780 kg/ha after 11 y, without canopy closure. The establishment of full-scale field trials to predict yields is crucial to making the cultivation of EMF a reality in tomorrow’s cropping landscape. Sustainable EMF cultivation utilizing trees in non-forested land could contribute to carbon storage, while providing revenue and other ecosystem services.
Amanita chuformis, a new species in the A. pseudogemmata-A. ballerina subclade of Amanita section Phalloideae, is described from China with both multi-gene phylogenetic and morphological data. This species occurs in subalpine coniferous forests in southwestern China and is characterized by its brownish pileus decorated with conical to patch-like volval remnants, a slightly striate pileal margin, a marginate basal bulb, and weakly amyloid to amyloid, subglobose to broadly ellipsoid basidiospores measuring 9.5–11 × 8–9.5 μm. Phylogenetic analyses based on internal transcribed spacer (ITS) region, the nuclear ribosomal RNA large subunit (nrLSU) and the genes for the polymerase II second largest subunit (RPB2) and for translation elongation factor 1-α (TEF1α) indicate A. chuformis is close to A. pseudogemmata and A. levistriata. The new species is described, illustrated and compared with closely related and similar species.
Two new species, Hyphoderma fissuratum and H. mopanshanense spp. nov., are proposed based on morphological and molecular evidences. Hyphoderma fissuratum is characterized by resupinate basidiomata with cracking hymenial surface, a monomitic hyphal system with generative hyphae bearing clamp connections, IKI–, CB–, and cylindrical, colorless, thin-walled, smooth basidiospores measuring (8.5–10.3 × 3–4 µm). Hyphoderma mopanshanense is characterized by an annual growth habit, slight gray to cream hymenial surface, and fusiform, thick-walled cystidia apically encrusted with crystal. Sequences of ITS and LSU nrRNA gene regions of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony and Bayesian inference methods. These phylogenetic analyses based on molecular data of ITS and nLSU sequences showed that two Hyphoderma new species formed a well supported monophyletic lineage distinct from other related species and then H. fissuratum grouped with H. medioburiense and H. roseocremeum. Hyphoderma mopanshanense grouped with H. setigerum.
A survey of yeasts associated with apricots was carried out in May 2019. Two strains isolated from two fresh apricots were identified as a novel species of the genus Colacogloea based on a multi locus phylogenetic analysis, and physiological and biochemical tests. The two strains differed from any hitherto known Colacogloea species by at least 18 nucleotide substitutions (3%) in the D1/D2 domains of the LSU rRNA gene and by more than 10% mismatches in the ITS region. Also, the two strains differed phylogenetically from their closest relatives, C. falcata and C. diffluens, in its inability to assimilate galactose, D-xylose and citrate. The new species C. armeniacae sp. nov. is proposed here to accommodate those two strains.
The resinicolous fungi Sarea difformis and S. resinae (Sareomycetes) were taxonomically revised on the basis of morphological observations and phylogenetic analyses of the nucleotide sequences of the nSSU-LSU-rpb1-rpb2-mtSSU genes. The results of phylogenetic analyses show that S. difformis and S. resinae are grouped with members of Xylonomycetes. According to the results of phylogenetic analyses and their sexual and asexual morphs resemblance, Sareomycetes is synonymized with Xylonomycetes. Although Tromera has been considered a synonym of Sarea based on the superficial resemblance of the sexual morph, we show that they are distinct genera and Tromera should be resurrected to accommodate T. resinae (= S. resinae).Xylonomycetes was morphologically re-circumscribed to comprise a single family (Xylonaceae) with four genera (Sarea, Trinosporium, Tromera, and Xylona) sharing an endophytic or plant saprobic stage in their lifecycle, ascostroma-type ascomata with paraphysoid, Lecanora-type bitunicate asci, and pycnidial asexual morphs. Phylogenetic analyses based on ITS sequences and environmental DNA (eDNA) implied a worldwide distribution of the species. Although Symbiotaphrinales has been treated as a member of Xylonomycetes in previous studies, it was shown to be phylogenetically, morphologically, and ecologically distinct. We, therefore, treated Symbiotaphrinales as Pezizomycotina incertae sedis.
The Bipolaris setariae NY1 strain, isolated from a diseased green foxtail plant in Henan Province, China, showed strong pathogenicity towards green foxtail. In order to clarify the role of phytotoxic substances in the fungal pathogenicity, bioassay-directed isolation and bioactivity assays of secondary metabolites produced by the fungal strain were carried out. Five ophiobolins were obtained: 3-anhydro-ophiobolin A, 6-epi-ophiobolin A, 6-epi-ophiobolin B, 3-anhydro-6-epi-ophiobolin B and ophiobolin I. Bioassays on punctured and intact detached leaves of green foxtail indicated that 3-anhydro-ophiobolin A was the most phytotoxic, followed by 6-epi-ophiobolin A. The other three ophiobolins appeared to be inactive against green foxtail. The effects of 3-anhydro-ophiobolin A and 6-epi-ophiobolin A were synergistic. The symptoms on green foxtail caused by 3-anhydro-ophiobolin A or its mixture with 6-epi-ophiobolin A resembled those caused by the fungus. 3-Anhydro-ophiobolin A and 6-epi-ophiobolin A are likely the main pathogenic determinants of B. setariae. 6-epi-Ophiobolin A caused cytotoxicity against five kinds of human cancer cells: human colon adenocarcinoma cells (HCT-8), human liver cancer cells (Bel-7402), human gastric cancer cells (BGC-823), human lung adenocarcinoma cells (A549), and human ovarian adenocarcinoma cells (A2780). The results provide information for the development of herbicides and antitumor potential of the ophiobolin sesterterpenes.
Developing high-content strains of L-ergothioneine (EGT), an antioxidant amino acid, is an important breeding target for tamogitake mushroom, Pleurotus cornucopiae var. citrinopileatus. We constructed a genetic linkage map based on segregation analysis of markers in 105 F1 progenies. The loci of 245 markers, including 10 AFLP markers, 195 Rad markers, 2 mating type factors, and 38 gene markers, were mapped. The map contained 12 linkage groups with a total genetic distance of 906.8 cM, and an average marker interval of 4.0 cM. The population from crossing between tester monokaryon and F1 progenies was used to characterize quantitative trait loci (QTL) for EGT content. With composite interval mapping (CIM) method, QTL of EGT content were found to be located in linkage group 10, having a Logarithm of the odds (LOD) score of 2.53 with a 10.1% contribution rate. Moreover, a single nucleotide polymorphism (SNP), A/T, was identified in a gene region of the genome in the neighborhood where the QTL peak existed. This SNP genotype was in good agreement with the EGT phenotypes of each strain in the both QTL population and wild population. Thus, this SNP would have great potential value to use the marker-assisted selection (MAS) for this mushroom with high EGT content.