Examining the associations between a generalist feeder and a highly toxic host

Understanding the often antagonistic plant-herbivore interactions and how host defenses can influence herbivore dietary breadth is an area of ongoing study in ecology and evolutionary biology. Typically, host plants/fungi that produce highly noxious chemical defenses are only fed on by specialists. We know very little about generalist species that can feed and develop on a noxious host. One such example of generalists feeding on toxic host occurs in the mushroom-feeding Drosophila found in the immigrans-tripunctata radiation. Although these species are classified as generalists, their acceptable hosts include deadly Amanita species. In this study, we used behavioral assays to assess associations between one mushroom-feeding species, Drosophila guttifera, and the deadly Amanita phalloides. We conducted feeding assays to confirm the presence of cyclopeptide toxin tolerance. We then completed host preference assays in female flies and larvae and did not find a preference for toxic mushrooms in either. Finally, we assessed the effect of competition on oviposition preference. We found that the presence of a competitor's eggs on the preferred host was associated with the flies increasing the number of eggs laid on the toxic mushrooms. Our results highlight how access to a low competition host resource may help to maintain associations between a generalist species and a highly toxic host.

Determination of ibotenic acid and muscimol in species of the genus Amanita section Amanita from China

The genus Amanita sect. Amanita harbors approximately 150 species in the world, and 27 species have been recognized in China. Some of the species in China have continuously caused poisoning. The responsible toxins should be ibotenic acid (IBO) and muscimol (MUS). However, species of the section Amanita containing IBO and MUS and their systematic positions are unclear. In this study, the contents of IBO and MUS in 84 samples of 24 species in section Amanita were detected using UPLC‒MS/MS, and the distribution of toxin-containing species in the molecular phylogeny was analyzed by the combined (ITS, nrLSU, RPB2, TUB2 and TEF1-α) dataset using maximum likelihood (ML) analysis and Bayesian inference (BI). Our results indicated that 10 of the 24 species contained IBO and MUS ranging from 0.6125 to 32.0932 and 0.0056-5.8685 g/kg dry weight, respectively. Among these 10 species, the toxins of eight species, including Amanita altipes, A. concentrica, A. flavopantherina, A. griseopantherina, A. pseudopantherina, A. rubrovolvata, A. subglobosa and A. sychnopyramis, were detected for the first time. In addition, the IBO and MUS contents of A. subglobosa in different growth stages showed that both toxins decreased in the mature stage. The phylogenetic analysis showed that all species of sect. Amanita from China were divided into 5 groups. And IBO- and MUS-containing species were gathered in clades Ⅰ and Ⅳ, but not all of the species in the two clades contain the toxins. No presence of IBO and MUS in the species of clades Ⅱ, Ⅲ and Ⅴ were confirmed.

[Study on 4 cases of mushroom poisoning with amanita and identification of poison]

Different kinds of poisonous mushrooms contain different toxic components. Acute liver injury caused by amanita mushroom is the main cause of death from poisonous mushroom poisoning in China. Consumption of poisonous mushrooms has an incubation period, there is a false recovery period in the clinical process, and the early performance is slight and does not attract enough attention from doctors, and it is easy to miss the treatment opportunity. The clinical characteristics, treatment and identification of mushrooms containing amanita in 4 patients were analyzed in order to improve clinicians' understanding of the diagnosis and treatment of mushroom poisoning and early species identification.

[The research of liver failure in Banna miniature pigs caused by amanita exitialis]

Objective: To explore the characteristics of Banna miniature pig liver failure induced by amanita exitialis. Methods: From September to October 2020, a reverse high performance liquid chromatography (RP-HPLC) method was used to determine the toxin content of amanita exitialis solution, and 2.0 mg/kg amanita exitialis solution (α-amanitins+β-amanitins) was administered orally to Banna miniature pigs. Toxic symptoms, blood biochemical indexes and histopathological changes of liver, heart and kidney were observed at each time point. Results: All Banna miniature pigs died within 76 h of exposure, and different degrees of digestive tract symptoms such as nausea, vomiting and diarrhea appeared between 6 and 36 h. The biochemical indexes of alanine aminotransferase, aspartate aminotransferase, total bilirubin, lactate dehydrogenase, myoglobin, creatine kinase isoenzyme, blood urea nitrogen and creatinine increased significantly at 52 h after exposure, and the differences were statistically significant compared with 0 h (P<0.05). The bleeding of liver and heart was obvious under macroscopic and microscopic observation, hepatocyte necrosis, renal tubule epithelial cell swelling. Conclusion: Large dose of amanita exitialis can cause acute liver failure of Banna miniature pigs, which is in line with the pathophysiological characteristics of acute liver failure, and lays a foundation for further research on the toxic mechanism and detoxification drugs of amanita exitialis induced liver failure.

Historical biogeography and diversification of ringless Amanita (section Vaginatae) support an African origin and suggest niche conservatism in the Americas

Ectomycorrhizal fungi (ECM) sustain nutrient recycling in most terrestrial ecosystems, yet we know little about what major biogeographical events gave rise to present-day diversity and distribution patterns. Given the strict relationship between some ECM lineages and their hosts, geographically well-sampled phylogenies are central to understanding major evolutionary processes of fungal biodiversity patterns. Here, we focus on Amanita sect. Vaginatae to address global diversity and distribution patterns. Ancestral-state-reconstruction based on a 4-gene timetree with over 200 species supports an African origin between the late Paleocene and the early Eocene (ca. 56 Ma). Major biogeographic "out-of-Africa" events include multiple dispersal events to Southeast Asia (ca. 45-21 Ma), Madagascar (ca. 18 Ma), and the current Amazonian basin (ca. 45-36 Ma), the last two likely trans-oceanic. Later events originating in Southeast Asia involve Nearctic dispersal to North America (ca. 20-5 Ma), Oceania (Australia and New Zealand; ca. 15 Ma), and Europe (ca. 10-5 Ma). Subsequent dispersals were also inferred from Southeast Asia to East Asia (ca. 4 Ma); from North America to East Asia (ca. 11-8 Ma), Southeast Asia (ca. 19-2 Ma), Northern Andes (ca. 15 Ma), and Europe (ca. 15-2 Ma), respectively; and from the Amazon to the Caribbean region (ca. 25-20 Ma). Finally, we detected a significant increase in the net diversification rates in the branch leading to most northern temperate species in addition to higher state-dependent diversification rates in temperate lineages, consistent with previous findings. These results suggest that species of sect. Vaginatae likely have higher dispersal ability and higher adaptability to new environments, in particular compared to those of its sister clade, sect. Caesareae. Overall, the much wider distribution of A. sect. Vaginatae, from pan-tropical to pan-arctic, provides a unique window to understanding niche conservatism across a species-rich clade of ECM fungi.

Intracellular sequestration of cadmium and zinc in ectomycorrhizal fungus Amanita muscaria (Agaricales, Amanitaceae) and characterization of its metallothionein gene

Amanita muscaria is an ectomycorrhizal mushroom that commonly grows at metal-polluted sites. Sporocarps from the lead smelter-polluted area near Příbram (Central Bohemia, Czech Republic) showed elevated concentrations of Cd and Zn. Size exclusion chromatography of the cell extracts of the sporocarps from both polluted and unpolluted sites indicated that substantial part of intracellular Cd and Zn was sequestered in 6-kDa complexes, presumably with metallothionein(s) (MT). When the cultured mycelial isolates were compared, those from Příbram were more Cd-tolerant and accumulated slightly less Cd and Zn than those from the unpolluted site. The analysis of the available A.muscaria sequence data returned a 67-amino acid (AA) MT encoded by the AmMT1 gene. Weak Cd and Zn responsiveness of AmMT1 in the mycelia suggested its metal homeostasis function in A.muscaria, rather than a major role in detoxification. The AmMT1 belongs to a ubiquitous peptide group in the Agaricomycetes consisting of 60-70-AA MTs containing seven cysteinyl domains and a conserved histidyl, features observed also in a newly predicted, atypical 45-AA RaMT1 of the Zn-accumulator Russula bresadolae in which the C-terminal cysteinyl domains VI and VII are missing. Heterologous expression in metal-sensitive yeast mutants indicated that AmMT1 and RaMT1 encode functional peptides that can protect cells against Cd, Zn, and Cu toxicity. The metal protection phenotype observed in yeasts with mutant variants of AmMT1 and RaMT1 further indicated that the conserved histidyl seems to play a structural, not metal binding role, and the cysteinyls of the C-terminal domains VI and VII are important for Cu binding. The data provide an important insight into the metal handling of site-associated ectomycorrhizal species disturbed by excess metals and the properties of MTs common in Agaricomycetes.

Genes and evolutionary fates of the amanitin biosynthesis pathway in poisonous mushrooms

Why do unrelated poisonous mushrooms (Amanita, Galerina, and Lepiota) make the same deadly toxin, α-amanitin? One of the most effective and fast strategies for organisms to acquire new abilities is through horizontal gene transfer (HGT). With the help of genome sequencing and the finding of two genes for the amanitin biosynthetic pathway, we demonstrate that the pathway distribution resulted from HGT probably through an unknown ancestral fungal donor. In Amanita mushrooms, the pathway evolved, through a series of gene manipulations, to produce very high levels of toxins, generating “the deadliest mushroom known to mankind.”

The deadly toxin α-amanitin is a bicyclic octapeptide biosynthesized on ribosomes. A phylogenetically disjunct group of mushrooms in Agaricales (Amanita, Lepiota, and Galerina) synthesizes α-amanitin. This distribution of the toxin biosynthetic pathway is possibly related to the horizontal transfer of metabolic gene clusters among taxonomically unrelated mushrooms with overlapping habitats. Here, our work confirms that two biosynthetic genes, P450-29 and FMO1, are oxygenases important for amanitin biosynthesis. Phylogenetic and genetic analyses of these genes strongly support their origin through horizontal transfer, as is the case for the previously characterized biosynthetic genes MSDIN and POPB. Our analysis of multiple genomes showed that the evolution of the α-amanitin biosynthetic pathways in the poisonous agarics in the Amanita, Lepiota, and Galerina clades entailed distinct evolutionary pathways including gene family expansion, biosynthetic genes, and genomic rearrangements. Unrelated poisonous fungi produce the same deadly amanitin toxins using variations of the same pathway. Furthermore, the evolution of the amanitin biosynthetic pathway(s) in Amanita species generates a much wider range of toxic cyclic peptides. The results reported here expand our understanding of the genetics, diversity, and evolution of the toxin biosynthetic pathway in fungi.

Squamanitaceae and three new species of Squamanita parasitic on Amanita basidiomes

The systematic position of the enigmatically mycoparasitic genus Squamanita (Agaricales, Basidiomycota) together with Cystoderma, Phaeolepiota, Floccularia, and Leucopholiota is largely unknown. Recently they were recognized as Squamanitaceae, but previous studies used few DNA markers from a restricted sample of taxa from the family and lacked a formal taxonomic treatment. In this study, with newly generated sequences of the type of the genus Squamanita, S. schreieri, and several additional species of the family, the phylogeny is reinvestigated with a concatenated (18S-5.8S-nrLSU-RPB2-TEF1-α) dataset. This study reveals that Cystoderma, Phaeolepiota, Squamanita, Floccularia, and Leucopholiota are a monophyletic clade with strong statistical support in Bayesian analysis and form Squamanitaceae. Phaeolepiota nested within Cystoderma; Squamanita, Leucopholiota, and Floccularia clustered together as two monophyletic subclades; and Squamanita was present as a monophyletic clade with strong statistical support in both Maximum Likelihood and Bayesian analyses. The family name Squamanitaceae is formally emended and a detailed taxonomic treatment is presented to accommodate the five genera. Meanwhile, another concatenated (18S-ITS-nrLSU-RPB2-TEF1-α) dataset is used to investigate phylogenetic relationships and species delimitation in Squamanita. Our data indicates that “S. umbonata” from the Northern hemisphere forms two species complexes, one complex includes six specimens from North America, Europe, and East Asia, the other includes two specimens from Central America and North America respectively. Futhermore, species of Squamanita can parasitize species of Amanita, besides other fungal species. Squamanita mira parasitizes A. kitamagotake (A. sect. Caesareae), while S. orientalis and S. sororcula are parasites of species belonging to the A. sepiacea complex (A. sect. Validae). “Squamanita umbonata” from Italy occurs on A. excelsa (A. sect. Validae). Three new species of Squamanita from East Asia, viz. S. mira, S. orientalis and S. sororcula are documented with morphological, multi-gene phylogenetic, and ecological data, along with line drawings and photographs, and compared with similar species. A key for identification of the global Squamanita species is provided.

Diversity of MSDIN family members in amanitin-producing mushrooms and the phylogeny of the MSDIN and prolyl oligopeptidase genes

Background

Amanitin-producing mushrooms, mainly distributed in the genera Amanita, Galerina and Lepiota, possess MSDIN gene family for the biosynthesis of many cyclopeptides catalysed by prolyl oligopeptidase (POP). Recently, transcriptome sequencing has proven to be an efficient way to mine MSDIN and POP genes in these lethal mushrooms. Thus far, only A. palloides and A. bisporigera from North America and A. exitialis and A. rimosa from Asia have been studied based on transcriptome analysis. However, the MSDIN and POP genes of many amanitin-producing mushrooms in China remain unstudied; hence, the transcriptomes of these speices deserve to be analysed.

Results

In this study, the MSDIN and POP genes from ten Amanita species, two Galerina species and Lepiota venenata were studied and the phylogenetic relationships of their MSDIN and POP genes were analysed. Through transcriptome sequencing and PCR cloning, 19 POP genes and 151 MSDIN genes predicted to encode 98 non-duplicated cyclopeptides, including α-amanitin, β-amanitin, phallacidin, phalloidin and 94 unknown peptides, were found in these species. Phylogenetic analysis showed that (1) MSDIN genes generally clustered depending on the taxonomy of the genus, while Amanita MSDIN genes clustered depending on the chemical substance; and (2) the POPA genes of Amanita, Galerina and Lepiota clustered and were separated into three different groups, but the POPB genes of the three distinct genera were clustered in a highly supported monophyletic group.

Conclusions

These results indicate that lethal Amanita species have the genetic capacity to produce numerous cyclopeptides, most of which are unknown, while lethal Galerina and Lepiota species seem to only have the genetic capacity to produce α-amanitin. Additionally, the POPB phylogeny of Amanita, Galerina and Lepiota conflicts with the taxonomic status of the three genera, suggesting that underlying horizontal gene transfer has occurred among these three genera.

Comparative Mitogenome Analysis Reveals Mitochondrial Genome Differentiation in Ectomycorrhizal and Asymbiotic Amanita Species

In this present study, we assembled and analyzed the mitogenomes of two asymbiotic and six ectomycorrhizal Amanita species based on next-generation sequencing data. The size of the eight Amanita mitogenomes ranged from 37,341 to 137,428 bp, and we considered introns to be one of the main factors contributing to the size variation of Amanita. The introns of the cox1 gene experienced frequent gain/loss events in Amanita; and the intron position class cox1P386 was lost in the six ectomycorrhizal Amanita species. In addition, ectomycorrhizal Amanita species had more repetitive sequences and fewer intergenic sequences than asymbiotic Amanita species in their mitogenomes. Large-scale gene rearrangements were detected in the Amanita species we tested, including gene displacements and inversions. On the basis of the combined mitochondrial gene set, we reconstructed the phylogenetic relationships of 66 Basidiomycetes. The six ectomycorrhizal Amanita species were of single origin, and the two saprophytic Amanita species formed two distinct clades. This study is the first to elucidate the functions of the mitogenome in the evolution and ecological adaptation of Amanita species.

Triangular Test of Amanita Mushrooms by Using Electronic Nose and Sensory Panel

This work aims to advance understanding of the differentiation of mushroom species through electronic devices that use sensors of various technologies and techniques for pattern recognition, comparing mainly volatile substances that emanate from them. In this first phase, the capacity of human olfaction to differentiate between the smell released by different wild mushrooms of the genus Amanita was analyzed by means of a triangular sensory test, comparing later the data to those obtained for the same samples with an electronic nose in a similar test. The results, still very preliminary, encourage imagining the wide application that these techniques will have and the feedback that this application can suppose for the training of the sense of human olfaction.

Universal identification of lethal amanitas by using Hyperbranched rolling circle amplification based on α-amanitin gene sequences

Hyperbranched rolling circle amplification (HRCA) with a padlock probe (PLP) targeting the α-amanitin (α-AMA) gene, as a screening tool for the universal identification of lethal amanitas, was established in this study. With the isothermal HRCA assay, all of the lethal Amanita species tested from Phalloideae (10) were positive, while the non-Phalloideae Amanita species (15) and three amanitin-containing Lepiota and Galerina species were negative. Furthermore, the PLP based on α-AMA sequences from lethal Amanita species was effective for Amanita α-AMA, but not Amanita β-AMA or non-Amanita α-AMA. HRCA sensitivity was 100-fold higher than conventional PCR with a detection limit of 100 copies (recombinant plasmid containing α-AMA), and 0.2% lethal amanitas could be detected in dry mushroom blends. The HRCA method presented provided a rapid, specific, sensitive and low-cost identification tool for lethal amanitas.

Two new species of Amanitasect.Phalloideae from Africa, one of which is devoid of amatoxins and phallotoxins

Two new species of Amanitasect.Phalloideae are described from tropical Africa (incl. Madagascar) based on both morphological and molecular (DNA sequence) data. Amanitabweyeyensissp. nov. was collected, associated with Eucalyptus, in Rwanda, Burundi and Tanzania. It is consumed by local people and chemical analyses showed the absence of amatoxins and phallotoxins in the basidiomata. Surprisingly, molecular analysis performed on the same specimens nevertheless demonstrated the presence of the gene sequence encoding for the phallotoxin phallacidin (PHA gene, member of the MSDIN family). The second species, Amanitaharkonenianasp. nov. was collected in Tanzania and Madagascar. It is also characterised by a complete PHA gene sequence and is suspected to be deadly poisonous. Both species clustered together in a well-supported terminal clade in multilocus phylogenetic inferences (including nuclear ribosomal partial LSU and ITS-5.8S, partial tef1-α, rpb2 and β-tubulin genes), considered either individually or concatenated. This, along with the occurrence of other species in sub-Saharan Africa and their phylogenetic relationships, are briefly discussed. Macro- and microscopic descriptions, as well as pictures and line drawings, are presented for both species. An identification key to the African and Madagascan species of Amanitasect.Phalloideae is provided. The differences between the two new species and the closest Phalloideae species are discussed.

Mushroom Poisoning Cases in Dogs and Cats: Diagnosis and Treatment of Hepatotoxic, Neurotoxic, Gastroenterotoxic, Nephrotoxic, and Muscarinic Mushrooms

Ingestion of poisonous mushrooms by small animals can lead to liver failure, neurotoxicity, or gastrointestinal irritation. Although amanita poisoning can be lethal, ingestion of other toxic mushrooms is generally self-limiting and not life threatening. Most cases are undiagnosed, as routine diagnostic tests only exist for amanitins and psilocin. Early detection of amanitin exposure can greatly aid in the therapeutic intervention by allowing veterinarians to make timely decisions regarding patient management. Treatment is generally supportive, but specific therapeutic measures exist for amanitin and psilocin exposures.

The MSDIN family in amanitin-producing mushrooms and evolution of the prolyl oligopeptidase genes

The biosynthetic pathway for amanitins and related cyclic peptides in deadly Amanita (Amanitaceae) mushrooms represents the first known ribosomal cyclic peptide pathway in the Fungi. Amanitins are found outside of the genus in distantly related agarics Galerina (Strophariaceae) and Lepiota (Agaricaceae). A long-standing question in the field persists: why is this pathway present in these phylogenetically disjunct agarics? Two deadly mushrooms, A. pallidorosea and A. subjunquillea, were deep sequenced, and sequences of biosynthetic genes encoding MSDINs (cyclic peptide precursor) and prolyl oligopeptidases (POPA and POPB) were obtained. The two Amanita species yielded 29 and 18 MSDINs, respectively. In addition, two MSDIN sequences were cloned from L. brunneoincarnata basidiomes. The toxin MSDIN genes encoding amatoxins or phallotoxins from the three genera were compared, and a phylogenetic tree constructed. Prolyl oligopeptidase B (POPB), a key enzyme in the biosynthetic pathway, was used in phylogenetic reconstruction to infer the evolutionary history of the genes. Phylogenies of POPB and POPA based on both coding and amino acid sequences showed very different results: while POPA genes clearly reflected the phylogeny of the host species, POPB did not; strikingly, it formed a well-supported monophyletic clade, despite that the species belong to different genera in disjunct families. POPA, a known house-keeping gene, was shown to be restricted in a branch containing only Amanita species and the phylogeny resembled that of those Amanita species. Phylogenetic analyses of MSDIN and POPB genes showed tight coordination and disjunct distribution. A POPB gene tree was compared with a corresponding species tree, and distances and substitution rates were compared. The result suggested POPB genes have significant smaller distances and rates than the house-keeping rpb2, discounting massive gene loss. Under this assumption, the incongruency between the gene tree and species tree was shown with strong support. Additionally, k-mer analyses consistently cluster Galerina and Amanita POPB genes, while Lepiota POPB is distinct. Our result suggests that horizontal gene transfer (HGT), at least between Amanita and Galerina, was involved in the acquisition of POPB genes, which may shed light on the evolution of the α-amanitin biosynthetic pathway.

Versatility of Prolyl Oligopeptidase B in Peptide Macrocyclization

Cyclic peptides are promising compounds for new chemical biological tools and therapeutics due to their structural diversity, resistance to proteases, and membrane permeability. Amatoxins, the toxic principles of poisonous mushrooms, are biosynthesized on ribosomes as 35mer precursor peptides, which are ultimately converted to hydroxylated bicyclic octapeptides. The initial cyclization steps, catalyzed by a dedicated prolyl oligopeptidase (POPB), involves removal of the 10-amino acid leader sequence from the precursor peptide and transpeptidation to produce a monocyclic octapeptide intermediate. The utility of POPB as a general catalyst for peptide cyclization was systematically characterized using a range of precursor peptide substrates produced either in E. coli or chemically. Substrates produced in E. coli were expressed either individually or in mixtures produced by codon mutagenesis. A total of 127 novel peptide substrates were tested, of which POPB could cyclize 100. Peptides of 7-16 residues were cyclized at least partially. Synthetic 25mer precursor peptide substrates containing modified amino acids including d-Ala, β-Ala, N-methyl-Ala, and 4-hydroxy-Pro were also successfully cyclized. Although a phalloidin heptapeptide with all L amino acids was not cyclized, partial cyclization was seen when l-Thr at position #5 was replaced with the naturally occurring D amino acid. POPB should have broad applicability as a general catalyst for macrocyclization of peptides containing 7 to at least 16 amino acids, with an optimum of 8-9 residues.

Mushroom poisoning: a retrospective study concerning 11-years of admissions in a Swiss Emergency Department

Wild mushroom intoxication is an unusual cause of toxic ingestion in Europe. A great diversity of clinical symptoms may arise depending on the variety of wild mushrooms ingested. These initial symptoms are often non-specific, with frequent gastrointestinal symptoms, and have no direct correlation with the outcome. Therefore, management of mushroom poisoning and risk evaluation are a challenge for emergency clinicians. We retrospectively reviewed all cases of mushroom poisoning identified in the ED database spanning 11 years. Demographic and clinical data, time from consumption to symptoms, type of mushrooms, the number of patients presenting at the same time, treatment(s) provided, length of stay, discharge diagnosis, in-hospital mortality, and serious complications were evaluated. We identify 87 cases of mushroom poisoning. The most common symptoms are nausea and vomiting (71 cases, 82%), followed by diarrhea (68%), syncope (10%), abdominal pain (8%), and hallucinations (7%). Sixty-four patients (74%) exhibited early symptoms (appearance <6 h after ingestion) and 23 (26%) late symptoms (appearance >6 h after ingestion). Eleven patients (13%) required hospitalization over 24 h. Patients with late symptoms tended to have longer in-hospital lengths of stay. Only one patient had Amanita phalloides intoxication, with a favorable outcome. Thirty-eight patients (44%) were involved in cluster presentations. Mushroom poisoning is an unusual but potentially severe form of intoxication. Patients presenting with late-appearing symptoms (>6 h) are associated with a higher risk of A. phalloides intoxication, and therefore require specific investigation and management.

Defining the phylogenetic position of Amanita species from Andean Colombia

Amanita is a worldwide-distributed fungal genus, with approximately 600 known species. Most species within the genus are ectomycorrhizal (ECM), with some saprotrophic representatives. In this study, we constructed the first comprehensive phylogeny including ECM species from Colombia collected in native Quercus humboldtii forests and in introduced Pinus patula plantations. We included 8 species (A. brunneolocularis, A. colombiana, A. flavoconia, A. fuligineodisca, A. muscaria, A. rubescens, A. sororcula, and A. xylinivolva) out of 16 species reported for the country, two new reports: A. citrina and A. virosa, and a new variety A. brunneolocularis var. pallida. Morphological taxonomic keys together with a phylogenetic approach using three nuclear gene regions: partial nuc rDNA 28S nuc rDNA internal transcribed spacers ITS1 and ITS2 and partial translation elongation factor 1-α gene (TEF1), were used to classify the specimens. Several highly supported clades were obtained from the phylogenetic hypotheses obtained by Bayesian inference and maximum likelihood approaches, allowing us to position the Colombian collections in a coherent infrageneric level and to contribute to the knowledge of local Amanita diversity.

Determination of cyclopeptide toxins in Amanita subpallidorosea and Amanita virosa by high-performance liquid chromatography coupled with high-resolution mass spectrometry

Amanita subpallidorosea is a recently discovered lethal Amanita sect. Phalloideae species found in China that is clustered with A. virosa in the same clade based on molecular phylogenetic analysis. However, the cyclopeptide toxin contents of these lethal mushrooms remain poorly studied. In this study, the cyclopeptide toxins in A. subpallidorosea were reported for the first time and the cyclopeptide compositions of A. subpallidorosea and A. virosa species were systematically analyzed. Thirteen cyclopeptides and two unknown compounds were identified or observed from these two lethal mushrooms by high-performance liquid chromatography coupled with high-resolution mass spectrometry. Of the known cyclopeptides, the virotoxins alaviroidin, viroisin, and viroidin, which were previously thought to be restricted to A. virosa, were identified in A. subpallidorosea. The cyclopeptide compositions showed that there are diversities in the kinds and levels of amatoxins, phallotoxins, and virotoxins between A. subpallidorosea and A. virosa species, and that the amount of total toxins in the tested A. subpallidorosea is significantly higher than that in the tested A. virosa. Furthermore, consistency of the cyclopeptide toxins with the molecular phylogenetic relationships was demonstrated.

Cyclopeptide toxins of lethal amanitas: Compositions, distribution and phylogenetic implication

Lethal amanitas (Amanita sect. Phalloideae) are responsible for 90% of all fatal mushroom poisonings. Since 2000, more than ten new lethal Amanita species have been discovered and some of them had caused severe mushroom poisonings in China. However, the contents and distribution of cyclopeptides in these lethal mushrooms remain poorly known. In this study, the diversity of major cyclopeptide toxins in seven Amanita species from Eastern Asia and three species from Europe and North America were systematically analyzed, and a new approach to inferring phylogenetic relationships using cyclopeptide profile was evaluated for the first time. The results showed that there were diversities of the cyclopeptides among lethal Amanita species, and cyclopeptides from Amanita rimosa and Amanita fuligineoides were reported for the first time. The amounts of amatoxins in East Asian Amanita species were significantly higher than those in European and North American species. The analysis of distribution of amatoxins and phallotoxins in various Amanita species demonstrated that the content of phallotoxins was higher than that of amatoxins in Amanita phalloides and Amanita virosa. In contrast, the content of phallotoxins was significantly lower than that of amatoxins in all East Asian lethal Amanita species tested. However, the distribution of amatoxins and phallotoxins in different tissues showed the same tendency. Eight cyclopeptides and three unknown compounds were identified using cyclopeptide standards and high-resolution MS. Based on the cyclopeptide profiles, phylogenetic relationships of lethal amanitas were inferred through a dendrogram generated by UPGMA method. The results showed high similarity to the phylogeny established previously based on the multi-locus DNA sequences.

Four New Species of Amanita in Inje County, Korea

Amanita (Agaricales, Basidiomycota) is one of the most well-known genera composed of poisonous mushrooms. This genus of almost 500 species is distributed worldwide. Approximately 240 macrofungi were collected through an ongoing survey of indigenous fungi of Mt. Jeombong in Inje County, Korea in 2014. Among these specimens, 25 were identified as members of Amanita using macroscopic features. Specimens were identified to the species level by microscopic features and molecular sequence analyses of the internal transcribed spacer and large subunit of nuclear ribosomal RNA. We molecularly identified 13 Amanita species, with seven species matching previously recorded species, four species (A. caesareoides, A. griseoturcosa, A. imazekii, and A. sepiacea) new to Korea, and two unknown species.

High speciation rate at temperate latitudes explains unusual diversity gradients in a clade of ectomycorrhizal fungi

Understanding the patterns of biodiversity through time and space is a challenging task. However, phylogeny-based macroevolutionary models allow us to account and measure many of the processes responsible for diversity buildup, namely speciation and extinction. The general latitudinal diversity gradient (LDG) is a well-recognized pattern describing a decline in species richness from the equator polewards. Recent macroecological studies in ectomycorrhizal (EM) fungi have shown that their LDG is shifted, peaking at temperate rather than tropical latitudes. Here we investigate this phenomenon from a macroevolutionary perspective, focusing on a well-sampled group of edible EM mushrooms from the genus Amanita-the Caesar's mushrooms, which follow similar diversity patterns. Our approach consisted in applying a suite of models including (1) nontrait-dependent time-varying diversification (Bayesian analysis of macroevolutionary mixtures [BAMM]), (2) continuous trait-dependent diversification (quantitative-state speciation and extinction [QuaSSE]), and (3) diversity-dependent diversification. In short, results give strong support for high speciation rates at temperate latitudes (BAMM and QuaSSE). We also find some evidence for different diversity-dependence thresholds in "temperate" and "tropical" subclades, and little differences in diversity due to extinction. We conclude that our analyses on the Caesar's mushrooms give further evidence of a temperate-peaking LDG in EM fungi, highlighting the importance and the implications of macroevolutionary processes in explaining diversity gradients in microorganisms.

Production of (15)N-labeled α-amanitin in Galerina marginata

α-Amanitin is the major causal constituent of deadly Amanita mushrooms that account for the majority of fatal mushroom poisonings worldwide. It is also an important biochemical tool for the study of its target, RNA polymerase II. The commercial supply of this bicyclic peptide comes from Amanita phalloides, the death cap mushroom, which is collected from the wild. Isotopically labeled amanitin could be useful for clinical and forensic applications, but α-amanitin has not been chemically synthesized and A. phalloides cannot be cultured on artificial medium. Using Galerina marginata, an unrelated saprotrophic mushroom that grows and produces α-amanitin in culture, we describe a method for producing (15)N-labeled α-amanitin using growth media containing (15)N as sole nitrogen source. A key to success was preparing (15)N-enriched yeast extract via a novel method designated "glass bead-assisted maturation." In the presence of the labeled yeast extract and (15)N-NH4Cl, α-amanitin was produced with >97% isotope enrichment. The labeled product was confirmed by HPLC, high-resolution mass spectrometry, and NMR.

A review on the diversity, phylogeography and population genetics of Amanita mushrooms

Amanita mushrooms are important for both human beings and ecosystems. Some members in this genus are valued edible species, whereas some others are extremely poisonous, and most species are ectomycorrhizal. Significant progress has been made in recent years in our understanding of the diversity, phylogeography and population genetics of Amanita mushrooms. A significant reason for the progress was due to the increasing application of molecular methods in the analyses. In this review, we summarize the researches in the diversity, phylogeography and population genetics of Amanita mushrooms, with the focus on advances over the past 20 years. We also discussed future research directions, including several unresolved topical issues.

Horizontal transfer of carbohydrate metabolism genes into ectomycorrhizal Amanita

The genus Amanita encompasses both symbiotic, ectomycorrhizal fungi and asymbiotic litter decomposers; all species are derived from asymbiotic ancestors. Symbiotic species are no longer able to degrade plant cell walls. The carbohydrate esterases family 1 (CE1s) is a diverse group of enzymes involved in carbon metabolism, including decomposition and carbon storage. CE1 genes of the ectomycorrhizal A. muscaria appear diverged from all other fungal homologues, and more similar to CE1s of bacteria, suggesting a horizontal gene transfer (HGT) event. In order to test whether AmanitaCE1s were acquired horizontally, we built a phylogeny of CE1s collected from across the tree of life, and describe the evolution of CE1 genes among Amanita and relevant lineages of bacteria. CE1s of symbiotic Amanita were very different from CE1s of asymbiotic Amanita, and are more similar to bacterial CE1s. The protein structure of one CE1 gene of A. muscaria matched a depolymerase that degrades the carbon storage molecule poly((R)-3-hydroxybutyrate) (PHB). Asymbiotic Amanita do not carry sequence or structural homologues of these genes. The CE1s acquired through HGT may enable novel metabolisms, or play roles in signaling or defense. This is the first evidence for the horizontal transfer of carbohydrate metabolism genes into ectomycorrhizal fungi.

A rare case of amatoxin poisoning in the state of Texas

Ingestion of mushrooms from the genus Amanita can present detrimental consequences to the human body. The mushroom is frequently found in the coastal Pacific Northwest, Pennsylvania, New Jersey, and Ohio. Amanitin, one of the two distinct toxins isolated from the Amanita mushroom, is responsible for the majority of symptoms and signs seen with mushroom poisoning. Clinically, ingestion of these mushrooms can result in a wide range of clinical symptoms including nausea, vomiting, crampy abdominal pain, and diarrhea. There have been several case reports of patients who developed severe hepatic failure that required liver transplantation. Thus, it is important to recognize the symptoms early and treat the patients with the available agents including multidose activated charcoal, N-acetylcysteine, penicillin G, and Silybum. Through an extensive literature search, we found no published literature on amatoxin poisoning in the state of Texas. With new cases of amatoxin poisoning emerging in the state, it is important for healthcare providers and workers to have a better awareness and early recognition of the detrimental effects of Amanita species poisoning and to be educated to provide the proper care for this group of patients.

First syntheses of ectomycorrhizas between Afzelia africana Sm. (Caesalpinioideae) and native fungi from West Africa

Afzelia-associated fungi in Senegal were isolated from sporocarps, sclerotia and ectomycorrhizas. The choice of sterilizing agent was critical for the success of isolation. Osmic acid was more efficient than mercuric chloride, hydrogen peroxide and calcium hypochlorite. Isolates were tested for their ability to form mycorrhizas in vitro and their mycelia in pure culture were described. Sclerotia linked to mycorrhizas of Scleraderma verrucosum Pers. were also isolated and their infectivity checked. Among isolates from sporocarps, only Scleroderma dictvosparum Fat. and S. verrucosum Pers. formed ectomycorrhizas with Afzelia africana Sm. Two native Amanita spp. and two introduced isolates belonging to the genus Pisolithus did not form typical ectomycorrhizas although a normal mantle was observed.