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10 p.-6 fig., Lentinula is a broadly distributed group of fungi that contains the cultivated shiitake mushroom, L. edodes. We sequenced 24 genomes representing eight described species and several unnamed lineages of Lentinula from 15 countries on four continents. Lentinula comprises four major clades that arose in the Oligocene, three in the Americas and one in Asia–Australasia. To expand sampling of shiitake mushrooms, we assembled 60 genomes of L. edodes from China that were previously published as raw Illumina reads and added them to our dataset. Lentinula edodes sensu lato (s. lat.) contains three lineages that may warrant recognition as species, one including a single isolate from Nepal that is the sister group to the rest of L. edodes s. lat., a second with 20 cultivars and 12 wild isolates from China, Japan, Korea, and the Russian Far East, and a third with 28 wild isolates from China, Thailand, and Vietnam. Two additional lineages in China have arisen by hybridization among the second and third groups. Genes encoding cysteine sulfoxide lyase (lecsl) and γ-glutamyl transpeptidase (leggt), which are implicated in biosynthesis of the organosulfur flavor compound lenthionine, have diversified in Lentinula. Paralogs of both genes that are unique to Lentinula (lecsl 3 and leggt 5b) are coordinately up-regulated in fruiting bodies of L. edodes. The pangenome of L. edodes s. lat. contains 20,308 groups of orthologous genes, but only 6,438 orthogroups (32%) are shared among all strains, whereas 3,444 orthogroups (17%) are found only in wild populations, which should be targeted for conservation., This research was supported by the NSF awards DEB-1456588 to D.H. and DEB-1442113 to A.R., the Department of Energy award 0000238431 to D.H., the GENOBIOREF (BIO2017-86559-R) project of the Spanish Ministry of Science and Innovation (cofinanced by FEDER funds) to F.J.R.-D., S.C., and A.T.M., grant PID2019-103901GB-I00 of the Spanish Ministry of Science and Innovation to P.F., and the NIH award R56AI146096 to A.R. J.L.S. and A.R. were supported by the HHMI and the Burroughs Wellcome Fund. The work (proposal: 10.46936/10.25585/60001048) conducted by the US Department of Energy JGI (https://ror.org/04xm1d337), a DOE Office of Science User Facility, was supported by the Office of Science of the US Department of Energy operated under contract no. DE-AC02-05CH11231.

Most commercially circulating mushrooms are produced via cultivation using artificially produced mushroom substrates. However, after mushroom harvesting, the disposal of spent mushroom substrates (SMSs) is a serious problem for the mushroom industry owing to the need for a disposal site and the cost involved. Thus, in view of the possibility of recycling SMSs as a soil modifier, we examined the effect of soil mixed with SMSs on the infection of Arabidopsis leaves by Alternaria brassicicola, the causal agent of cabbage leaf spot. The mixing of SMSs used for Hypsizygus marmoreus, Pholiota microspora, Lyophyllum decastes, and Auricularia polytricha into culture soil suppressed the lesion formation caused by A. brassicicola. The defense responses of Arabidopsis were not induced by the culturing of these seedlings in soils containing SMSs. Suppressed lesion formation was observed after the seedlings were treated with volatiles emitted from SMSs that were incubated with soil for 7 days and used for H. marmoreus, P. microspora, L. decastes, A. polytricha, Lentinula edodes, and Cyclocybe cylindracea. The volatiles from the SMSs reduced the elongation of A. brassicicola hyphae. GC-MS analyses of extracts from the SMS containing soils led to the detection of various volatile compounds; among these, skatole, 2,4-di-tert-butylphenol, γ-dodecalactone, butyric acid, guaiacol, 6-amyl-2-pyrone, and 1-octen-3-ol were examined for inhibitory activity on A. brassicicola and found to suppress hyphae elongation. These findings indicate that the antifungal volatile compounds emitted by the SMSs suppress A. brassicicola infection.

A new species of Athelia, A. termitophila, from Japan is described and illustrated on the basis of morphological and phylogenetic analyses. Basidiomes of this species are characterized by having hyphae sometimes with clamp connections at the septa, basidia without clamp connections at the basal septa, and ellipsoid to ovoid basidiospores measuring 4.5–6 × 3–4.5 μm. In culture, mycelia produce pale brown, orange-brown to brown, globose sclerotia measuring 0.24–0.41 mm diam. The sclerotia are distinctly different in shape and size from those of other Athelia species, and are occasionally found inside the woody substrate beneath basidiomes. They are identical in shape and size to those of Fibularhizoctonia sp., also known as termite balls. Phylogenetic analysis using internal transcribed spacer (ITS) sequence data revealed that A. termitophila is the teleomorph of Fibularhizoctonia sp.

Tricholoma foliicola was taxonomically reevaluated based on analyses of the holotype and newly collected materials. Basidiospores of T. foliicola were irregularly ellipsoid, showing a cyanophilic reaction with or without tubercles. Phylogenetic analyses of the internal transcribed spacer (ITS) and large subunit 28S regions of the fungal nuclear ribosomal RNA gene demonstrated that T. foliicola is a species of Gerhardtia characterized by irregularly shaped basidiospores. Thus, we transferred this species to Gerhardtia foliicola comb. nov. Cultured mycelia of G. foliicola on malt extract agar medium produced cystidia covered with granules and abundant thallic conidia (arthroconidia), with both schizolytic and rhexolytic secession.

Fruiting bodies of ectomycorrhizal fungi were collected from different areas of Tottori Prefecture, Japan, during 2011–2015, and 18 species were identified by morphological characteristics and molecular analysis. Volatile compounds were extracted with acetone from fruiting bodies, and after concentration, the aqueous residue was extracted with n-hexane. The antifungal activities of the volatile extracts were assayed by inhibition of conidial germination of a phytopathogenic fungus, Alternaria brassicicola; the volatiles from Russula aff. anthracina, R. chloroides and R. senecis completely inhibited conidial at 1 ppm (w/v), the maximum concentration diffused as vapor. In addition, volatile compounds from R. aff. anthracina had remarkable antifungal activity against seven phytopathogenic fungi when tested at vapor concentrations of 0.2 ppm (w/v). The conidia of A. brassicicola did not germinate even after the removal of the volatile compounds, indicating that the active compound had fungicidal activity. The volatile compounds were isolated from the extracts of R. aff. anthracina, and isovelleral was identified as the major antifungal compound. Isovelleral was also detected in the extracts of R. chloroides and R. senecis and had significant antifungal activity against conidial germination of A. brassicicola at a vapor concentration as low as 0.05 ppm (w/v). This is the first report that isovelleral, the volatile compound produced by Russula spp., has antifungal activity against phytopathogenic fungi.

Tubulicium curvisporum sp. nov. frequently grows on the Japanese andromeda Pieris japonica on Honshu Island, Japan. Molecular phylogenetic analysis revealed that this species belongs to the genus Tubulicium, of the family Hydnodontaceae (Trechisporales). The present species is morphologically distinguishable from the other Tubulicium species, because of its strongly curved, sickle-shaped basidiospores, measuring 16.5–25.5 × 4.5–7 μm. In this study, the morphological descriptions, illustrations, and cultural characteristics of T. curvisporum are provided, as well as a key to the species of this genus.

In view of the possibility that spent mushroom substrates (SMSs) may be used as agricultural materials to prevent crop diseases, we examined the effect of treatment with a hot water extract from the SMS of Lentinula edodes on plant resistance to pathogenic infection. The extract of Le. edodes SMS was sprayed onto the leaves of rice plants, followed by inoculation of the leaves with the conidia of rice blast fungus. The development of lesions was suppressed by treatment with the SMS extract. The extract markedly inhibited the germination of Pyricularia oryzae conidia. We purified compounds 1, 2, and 3, which showed inhibitory effects on conidial germination, from the Le. edodes SMS extract of by successive solvent extraction, column chromatography, and preparative HPLC. Spectroscopic analyses revealed that 1, 2, and 3 were phenolic acids with two carboxyl groups in common.

Decomposition subsystems have an essential role in forest dynamics but few studies demonstrate the effect of microbial decay traits on seedling regeneration. In the present study, we focused on seedling regeneration on coarse woody material (CWM), which is an important regeneration site for forest tree species, and the effects of wood decay type according to fungal decay preference for wood structural components on seedling colonization. Effects of log properties including wood decay type and other environmental variables on seedling density were evaluated by ordination methods and generalized linear models. In total, 22 woody species were recorded as seedlings on Pinus densiflora logs. By ordination analysis, white rot in heartwood and brown rot in sapwood, as well as canopy openness and log diameter, showed significant association with seedling communities. The factors selected for a generalized linear model for explaining seedling densities of the two dominant seedling species Cryptomeria japonica and P. densiflora included brown rot in sapwood and white rot in heartwood, but the effects were different: a positive effect of brown rot on C. japonica and a negative effect of white rot on P. densiflora. These results suggested that wood decay type could induce niche separation between dominant tree species regenerating on CWM.

A new species of the genus Hydnum, H. minum, with whitish basidiomata, is described and illustrated from Japan based on morphological and phylogenetic analyses. This species is characterized by small basidiomata (1–2.5 cm in height), spinose hymenophores with small, conical to aciculate spines (0.5–1.7 mm in length, 150–250 μm in diameter), subclavate to suburniform basidia with 5–8 sterigmata, and subglobose to broadly ovoid basidiospores measuring 4.5–5.5 × 3–4.5 μm. In addition, H. albidum, H. albomagnum, newly recorded in Japan, and H. repandum var. album are analyzed using molecular tools. The four taxa were confirmed as each individual taxon by the molecular phylogenetic analysis using complete nuclear ribosomal internal transcribed spacer regions.

Dactylosporina brunneomarginata sp. nov., belonging to the family Physalacriaceae (Agaricales) is described and illustrated. This fungus differs from previously described species of Dactylosporina macroscopically by its viscid pileus and stipe surface when wet, the lamellae with dark brown edges, and microscopically by its gloeocystidioid pileo-, cheilo-, and caulocystidia with olive to yellow-brown oily content. This is the first report on Dactylosporina from Asia.