Taxonomy of Tricholoma in northern Europe based on ITS sequence data and morphological characters

No Evidence Was Found for the Presence of Terreolides, Terreumols or Saponaceolides H-S in the Fruiting Bodies of Tricholoma terreum (Basidiomycota, Agaricales)

Two different collections of the gilled wild fungus Tricholoma terreum, collected in Italy, were subjected to phytochemical analysis. The fungal material was confidently identified by analysis of the ITS genomic sequences. Using both HR-LC-MS and NMR techniques, no evidence was found for the presence in the fruiting bodies of terreolides, terreumols or saponaceolides H-S, in striking contrast with the isolation of these terpenoids by Chinese authors from a mushroom collected in France and identified as T. terreum. The main cytotoxic terpenoid identified and isolated from the extracts of the specimens investigated in this work was the C30 derivative saponaceolide B, which had been previously isolated from T. saponaceum and other T. terreum collections. Although saponaceolide B is a rather labile molecule, easily degradable by heat or in acidic conditions, our study indicated that none of the extraction protocols used produced saponaceolide H-S or terreolide/terreumol derivatives, thus excluding the possibility that the latter compounds could be extraction artifacts. Considered together, these findings point to the need for the unambiguous identification of mushroom species belonging to the complex genus Tricholoma, characterized by high variability in the composition of metabolites. Moreover, based on our data, T. terreum must be considered an edible mushroom.

New Tricholomalides D-G from the Mushroom Tricholoma ustaloides Grown in an Italian Beech Wood

Four novel seconeodolastane diterpenoids, named tricholomalides D-G, were isolated, together with the known tricholomalide C, from the fruiting bodies of Tricholoma ustaloides Romagn., a species belonging to the large Tricholoma genus of higher mushrooms (Basidiomycota, family Tricholomataceae). They were isolated through multiple chromatographic separations, and the structures, including the absolute configuration, were established through a detailed analysis of MS, NMR, and CD spectral data and comparison with related compounds reported in the literature, which has been thoroughly revised.

Near-complete de novo assembly of Tricholoma bakamatsutake chromosomes revealed the structural divergence and differentiation of Tricholoma genomes

Tricholoma bakamatsutake, which is an edible ectomycorrhizal fungus associated with Fagaceae trees, may have diverged before the other species in Tricholoma section Caligata. We generated a highly contiguous whole-genome sequence for T. bakamatsutake SF-Tf05 isolated in an Oak (Quercus salicina) forest in Japan. The assembly of high-fidelity long reads, with a median read length of 12.3 kb, resulted in 13 chromosome-sized contigs comprising 142,068,211 bases with an average guanine and cytosine (GC) content of 43.94%. The 13 chromosomes were predicted to encode 11,060 genes. A contig (122,566 bases) presumably containing the whole circular mitochondrial genome was also recovered. The chromosome-wide comparison of T. bakamatsutake and Tricholoma matsutake (TMA_r1.0) indicated that the basic number of chromosomes (13) was conserved, but the structures of the corresponding chromosomes diverged, with multiple inversions and translocations. Gene conservation and cluster analyses revealed at least 3 phylogenetic clades in Tricholoma section Caligata. Specifically, all T. bakamatsutake strains belonged to the "bakamatsutake" clade, which is most proximal to the "caligatum" clade consisting of Tricholoma caligatum and Tricholoma fulvocastaneum. The constructed highly contiguous nearly telomere-to-telomere genome sequence of a T. bakamatsutake isolate will serve as a fundamental resource for future research on the evolution and differentiation of Tricholoma species.

A fifty-locus phylogenetic analysis provides deep insights into the phylogeny of Tricholoma (Tricholomataceae, Agaricales)

As an ectomycorrhizal fungal genus that contains matsutake and other edible mushrooms, Tricholoma has great economic and ecological significance. However, the phylogenetic relationships within the genus remain unsettled. To clarify the infrageneric relationships of Tricholoma, including the identification of monophyletic subgenera and sections, three phylogenetic analyses were conducted employing single-locus (ITS), five-locus (ITS/ RPB2/EF-1α/MCM7/mtSSU) and 50-locus (45 single-copy orthologous genes plus the aforementioned ones) DNA nucleotide sequences. Our data indicated that ITS sequences could serve the species delimitation of Tricholoma in most cases and monophyletic groups recognition in some cases, and the five-locus dataset could resolve a section-level phylogeny of this genus, while the 50-locus dataset could clarify the delimitation of subgenera and settle the relationships among sections within this genus. A fifty-locus dataset was firstly employed to construct a robust phylogeny of Tricholoma. Based on this, a new infrageneric arrangement for the genus Tricholoma, with four subgenera, of which two are in accordance with the previous subgenera Pardinicutis and Sericeicutis, and eleven sections, is suggested. Subgenus Pardinicutis, occupying the basal position, only harbors sect. Pardinicutis, while the subg. Sericeicutis comprises sects. Lasciva and Sericella located at the sub-basal position with good support. Subgenus Terrea is newly erected here and consists of sect. Terrea, sect. Atrosquamosa and two as yet unnamed phylogenetic lineages. Besides an unnamed section-level lineage, subg. Tricholoma consists of sects. Genuina, Muscaria, Rigida, Tricholoma, Fucata and Matsutake, of which the two latter are newly proposed. The previously defined subg. Contextocutis is clustered within subg. Tricholoma and is a synonym of the latter. Tricholoma colossus, T. acerbum and their allies, which used to be allocated in sect. Megatricholoma (or genus Megatricholoma), are relocated to sect. Genuina since they form a strongly supported monophyletic group and share rusty or black spots on lamellae with other species in this section. Taxonomic descriptions of the new infrageneric taxa and a key to subgenera and sections of the genus Tricholoma are presented. Citation: Ding XX, Xu X, Cui YY, et al. 2023. A fifty-locus phylogenetic analysis provides deep insights into the phylogeny of Tricholoma (Tricholomataceae, Agaricales). Persoonia 50: 1-26. https://doi.org/10.3767/persoonia.2023.50.01.

New Tricholidic Acid Triterpenoids from the Mushroom Tricholoma ustaloides Collected in an Italian Beech Wood

The secondary metabolites produced by Tricholoma ustaloides Romagn., a mushroom species belonging to the large Tricholoma genus (Basidiomycota, Tricholomataceae), are unknown. Therefore, encouraged by the interesting results obtained in our previous chemical analyses of a few Tricholoma species collected in Italian woods, we aimed to investigate the secondary metabolites of Tricholoma ustaloides. The chemical analysis involved the isolation and characterization of secondary metabolites through an extensive chromatographic study. The structures of isolated metabolites, including the absolute configuration, were established based on a detailed analysis of MS, NMR spectroscopic, optical rotation, and circular dicroism data, and on comparison with those of related compounds reported in the literature. Two novel lanostane triterpenoids, named tricholidic acids B and C, together with triglycerides, a mixture of free fatty acids, five unidentified metabolites, and the known rare saponaceolides F and J, tricholidic acid, and tricholomenyn C, were isolated from an EtOAc extract of fruiting bodies of Tricholoma ustaloides that were collected in an Italian beech wood. This is the second example of isolation of tricholidic acid derivatives from a natural source. Saponaceolides F and J exhibited high cytotoxicity (IC₅₀ values ≤ 10 μM) against a panel of five human cancer cell lines. The toxicity against myeloid leukemia (HL-60), lung cancer (A-549), hepatocellular cancer (HepG2), renal cancer (Caki-1), and breast cancer (MCF-7) cells was higher than that shown by the very well-known cytotoxic drug cisplatin.

New findings on the fungal species <i>Tricholoma matsutake</i> from Ukraine, and revision of its taxonomy and biogeography based on multilocus phylogenetic analyses

Matsutake mushrooms are among the best-known edible wild mushroom taxa worldwide. The representative Tricholoma matsutake is from East Asia and the northern and central regions of Europe. Here, we report the existence of T. matsutake under fir trees in Eastern Europe (i.e., Ukraine), as confirmed by phylogenetic analysis of nine loci on the nuclear and mitochondrial genomes. All specimens from Japan, Bhutan, China, North Korea, South Korea, Sweden, Finland, and Ukraine formed a T. matsutake clade according to the phylogeny of the internal transcribed spacer region. The European population of T. matsutake was clustered based on the β2 tubulin gene, with a moderate bootstrap value. In contrast, based on analyses of three loci, i.e., rpb2, tef1, and the β2 tubulin gene, T. matsutake specimens sampled from Bhutan and China belonged to a clade independent of the other specimens of this species, implying a genetically isolated population. As biologically available type specimens of T. matsutake have not been designated since its description as a new species from Japan in 1925, we established an epitype of this fungus, sampled in a Pinus densiflora forest in Nagano, Japan.

Occurrence and Health Risk Assessment of Cadmium Accumulation in Three Tricholoma Mushroom Species Collected from Wild Habitats of Central and Coastal Croatia

This study deals with the biomonitoring of cadmium (Cd) heavy metal in the three selected Tricholoma mushroom species collected from wild habitats of central and coastal Croatia. For this, mushroom (T. columbetta: n = 38, T. portentosum: n = 35, and T. terreum: n = 34) and surface soil samples were collected from nine forest localities of Croatia and analyzed for Cd concentration using inductively coupled plasma−optical emission spectrometry (ICP−OES) through the acid digestion method. The findings revealed that Cd was present in Tricholoma spp. and surface soil. However, the maximum mean Cd concentration (mg/kg dry weight) was recorded in T. portentosum (cap: 0.98; stipe: 0.72), followed by T. columbetta (cap: 0.96; stipe: 0.73) and T. terreum (cap: 0.81; stipe: 0.63). The bioconcentration factor (BCF) value (>1) revealed that the selected Tricholoma spp. had the potential for Cd accumulation. Moreover, the principal component (PC) and hierarchical cluster (HC) analyses were used to derive the interactions and similarities between Cd levels Tricholoma spp. and sampling localities. The multivariate analysis suggested that central sampling localities had higher Cd levels as compared to coastal localities. However, the daily intake of metals (DIM < 0.426) and health risk index (HRI < 1) showed that there was no potential health risk associated with the consumption of selected Tricholoma spp. The findings of this study are helpful to understand the Cd accumulation behavior of wild edible Tricholoma spp. collected from Croatia.

The ectomycorrhizal association of Tricholoma matsutake and two allied species, T. bakamatsutake and T. fulvocastaneum, with native hosts in subtropical China

Accurate identification of edible ectomycorrhizal (ECM) mushrooms and their host trees in nature is key to commercial production for consumption. For the first time we describe the ectomycorrhizal association of the three most common species of edible matsutake mushrooms with their native host trees in Yunnan Province in China. We collected ECM samples from three different localities in subtropical forests known to be highly productive areas of Tricholoma. Additionally, we collected basidiomata of Tricholoma from the field and markets in Yunnan. ECM samples were analyzed using morphological and molecular methods. We conducted phylogenetic analyses of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and analyzed the intergenic spacer of cpDNA psbA-trnH to identify basidiomata and plant hosts, respectively. Three species of Tricholoma were identified: T. bakamatsutake, T. fulvocastaneum, and T. matsutake. Four ECM associations in the study area were detected: Tricholoma bakamatsutake + Castanopsis tibetana, T. fulvocastaneum + C. tibetana, T. fulvocastaneum + Pinus yunnanensis, and T. matsutake + P. yunnanensis. Detailed descriptions and illustrations of the ECM associations are presented.

Tricholoma alpinum, sp. nov., under five-needle pines in alpine and subalpine zones in Japan

Alpine regions in Japan are characterized by the Siberian dwarf pine, Pinus pumila. Although these regions are conserved as national parks due to their unique biome, few reports of the fungal biota are available. We examined mushroom fungi under such vegetation and found a unique yellowish-capped Tricholoma species. Multilocus molecular phylogenetic analyses and morphological observation of specimens showed that the Tricholoma species is very similar to T. fumosoluteum known in North America. The Japanese yellowish-capped T. aff. fumosoluteum had larger basidiospores and basidia and shorter pileipellis hyphae compared with T. fumosoluteum. Therefore, we describe the Japanese entity as a new species, T. alpinum.

Taxonomic revision of the Japanese Tricholoma ustale and closely related species based on molecular phylogenetic and morphological data

"Kakishimeji" identified as Tricholoma ustale and belonging to Tricholoma sect. Genuina is a common poisonous mushroom in Japan. Kakishimeji contains the toxic compound ustalic acid and causes digestive trouble. However, this fungus is consumed in some regions of Japan without any digestive issues. We clarified the probable species complex of Kakishimeji based on a phylogenetic analysis. We collected 89 basidioma specimens of Kakishimeji and related species from various forest sites in Japan and conducted phylogenetic analyses using 7 nuclear and mitochondrial gene sequences. Kakishimeji was found to consist of four distinct phylogenetic clades based on all DNA regions tested. Of these, two clades included European T. stans and T. albobrunneum type specimens. Another two clades consisted of sister clades to T. pessundatum and T. ustaloides. In addition, all four phylogenetic clades of Kakishimeji had different spore and basidium sizes. Therefore, we regarded the latter two clades as two new Tricholoma species: T. kakishimeji and T. kakishimejioides.

Tricholoma olivaceonigrum, a new species of the section Tricholoma (Agaricales) from Japan

A novel species of Tricholoma section Tricholoma, namely, T. olivaceonigrum, is described and illustrated based on samples found in an oak woods dominated by Quercus myrsinifolia, an evergreen oak, in Tottori Prefecture, western Japan. It is characterized by a conic-umbonate, dark-greenish olivaceous pileus with blackish innate fibrils; a whitish silky-fibrillose stipe, often faintly tinted pale yellow and with a narrowed subpointed base; subglobose to broadly elliptic spores; and fruiting in early winter. Phylogenetic analysis targeting the internal transcribed spacer region of the ribosomal RNA gene revealed that T. olivaceonigrum forms a well-supported clade sister to T. portentosum. Other morphologically and phylogenetically closely related species of the section Tricholoma are discussed.

Comparative Mitogenomic Analysis Reveals Dynamics of Intron Within and Between Tricholoma Species and Phylogeny of Basidiomycota

The genus of Tricholoma is a group of important ectomycorrhizal fungi. The overlapping of morphological characteristics often leads to the confusion of Tricholoma species classification. In this study, the mitogenomes of five Tricholoma species were sequenced based on the next-generation sequencing technology, including T. matsutake SCYJ1, T. bakamatsutake, T. terreum, T. flavovirens, and T. saponaceum. These five mitogenomes were all composed of circular DNA molecules, with sizes ranging from 49,480 to 103,090 bp. Intergenic sequences were considered to be the main factor contributing to size variations of Tricholoma mitogenomes. Comparative mitogenomic analysis showed that the introns of the Agaricales mitogenome experienced frequent loss/gain events. In addition, potential gene transfer was detected between the mitochondrial and nuclear genomes of the five species of Tricholoma. Evolutionary analysis showed that the rps3 gene of the Tricholoma species was under positive selection or relaxed selection in the evolutionary process. In addition, large-scale gene rearrangements were detected between some Tricholoma species. Phylogenetic analysis using the Bayesian inference and maximum likelihood methods based on a combined mitochondrial gene set yielded identical and well-supported tree topologies. This study promoted the understanding of the genetics, evolution, and phylogeny of the Tricholoma genus and related species.

Testing spore amyloidity in Agaricales under light microscope: the case study of Tricholoma

Although species of the genus Tricholoma are currently considered to produce inamyloid spores, a novel standardized method to test sporal amyloidity (which involves heating the sample in Melzer's reagent) showed evidence that in the tested species of this genus, which belong in all 10 sections currently recognized from Europe, the spores are amyloid. In two species, T. josserandii and T. terreum, the spores are also partly dextrinoid. This result provides strong indication that a positive reaction of the spores in Melzer's reagent could be a character shared by all genera in Tricholomataceae s. str.

Notes, outline and divergence times of Basidiomycota

The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406–430 Mya, classes are 211–383 Mya, and orders are 99–323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27–178 Mya, Pucciniomycotina from 85–222 Mya, and Ustilaginomycotina from 79–177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution.

The Yellow Knight Fights Back: Toxicological, Epidemiological, and Survey Studies Defend Edibility of Tricholoma equestre

Rhabdomyolysis, a condition associated with the consumption of Yellow Knight mushrooms (Tricholoma equestre), was first reported in 2001. In response, some countries began to consider the mushroom as poisonous, whereas in others it is still consumed. In the present study, a nationwide survey of Polish mushroom foragers (n = 1545) was conducted to estimate the frequency of T. equestre consumption. The epidemiological database on mushroom poisonings in Poland was analyzed from the year 2008. Hematological and biochemical parameters were followed for a week in 10 volunteers consuming 300 g of molecularly identified T. equestre. More than half the foragers had consumed T. equestre at least once in their lifetime and a quarter had consumed it consecutively. The frequency of adverse events was low and no rhabdomyolysis was reported. The toxicological database indicated that mushrooms from the Tricholoma genus caused poisonings less frequently than mushrooms with well-established edibility and not a single case of rhabdomyolysis has been reported within the last decade. The volunteers consuming T. equestre revealed no hematological or biochemical alterations and no adverse effects were observed. The findings of this study support the view that T. equestre is edible if consumed in rational amounts by healthy subjects.

Diversity and taxonomy of Tricholoma species from Yunnan, China, and notes on species from Europe and North America

Although taxonomic knowledge on Tricholoma (Agaricales, Basidiomycota) is fairly comprehensive in northwest Europe, knowledge of the global diversity and distribution of Tricholoma spp. is still sparse. In this study, the diversity and distribution of some Tricholoma spp. are analyzed by morphological and molecular methods based on 70 collections from Yunnan, China, 45 from central Europe, 32 from Colorado, USA, 9 from Japan, and 3 from Ukraine. A Holarctic distribution is suggested for several species, based on collections and nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) sequences. Six species new to science are formally described from Yunnan: five in existing sections, Tricholoma forteflavescens, T. olivaceoluteolum, T. melleum, T. olivaceum, and T. sinoportentosum, and one, T. muscarioides, in the newly described section Muscaria alongside several previously described species. Additional putatively new species cannot be formally described because they lack sufficient material. Tricholoma foliicola is recognized as a species of the genus Gerhardtia.

New Terpenoids from Tricholoma saponaceum

Two new terpenoids, saponaceolide T (7), and lanostane triterpenoid saponaceol D (11), were isolated from an EtOAc extract of Tricoloma saponaceum fruiting bodies and their structures have been established by spectroscopic analysis. In addition, known saponaceolides A (1), C (3), F (5), H (6), together with cerevisterol and fasciculol B depsipeptides pardinol B (9) and D (10), were isolated. Representative saponaceolides exhibited high antiproliferative activities against A549 and HEP G2 human tumor cell lines.

Secondary Metabolites Isolated fromTricholomaSpecies (Basidiomycota, Tricholomatacee): A Review

The large mushroom genus Tricholoma (Fr.) Staude comprises hundreds of species growing worldwide. Phytochemical studies on the contents of these mushrooms have been increasing steadily in the last decades; this review is the first complete report about the secondary metabolites isolated to date (January 2018) from the fruiting bodies, with the exclusion of most volatile constituents. The structures, presumed biogenesis, and bioactivities of identified compounds, divided in families according to their biogenesis, are critically discussed. A brief chemotaxonomic discussion of the genus Tricholoma is included in the final part of the review.

Is the Yellow Knight Mushroom Edible or Not? A Systematic Review and Critical Viewpoints on the Toxicity of Tricholoma equestre

There is no scientific consensus regarding the safety of the Yellow Knight mushroom Tricholoma equestre (L.) P.Kumm. Following reports of cases of intoxication involving effects such as rhabdomyolysis, and supportive observations from in vivo experimental models, T. equestre is considered as a poisonous mushroom in some countries while in others it is still widely collected from the wild and consumed every year. In this paper, we review all the available information on T. equestre including its morphological and molecular characterization, nutritional value, levels of contaminants observed in fruiting bodies, the possibility of mistake with species that are morphologically similar, and the in vivo data on safety and cases of human intoxication. Based on available data, it is suggested that T. equestre cannot be considered as a toxic species and does not appear to exhibit any greater health threat than other mushroom species currently considered as edible. More care should be taken when reporting cases of human poisoning to fully identify T. equestre as the causative agent and to exclude a number of interfering factors. Specific guidelines for reporting future cases of poisoning with T. equestre are outlined in this paper. Any future research involving T. equestre should present the results of molecular phylogenetic analyses.