Lethal amanitas (Amanita section Phalloideae) are a group of wild, fatal mushrooms causing many poisoning cases worldwide. However, the diversity and evolutionary history of these lethal mushrooms remain poorly known due to the limited sampling and insufficient gene fragments employed for phylogenetic analyses. In this study, five gene loci (nrLSU, ITS, rpb2, ef1-α and β-tubulin) with a widely geographic sampling from East and South Asia, Europe, North and Central America, South Africa and Australia were analysed with maximum-likelihood, maximum-parsimony and Bayesian inference methods. Biochemical analyses were also conducted with intention to detect amatoxins and phalloidin in 14 representative samples. Lethal amanitas were robustly supported to be a monophyletic group after excluding five species that were provisionally defined as lethal amanitas based on morphological studies. In lethal amanitas, 28 phylogenetic species were recognised by integrating molecular phylogenetic analyses with morphological studies, and 14 of them represented putatively new species. The biochemical analyses indicated a single origin of cyclic peptide toxins (amatoxins and phalloidin) within Amanita and suggested that this kind of toxins seemed to be a synapomorphy of lethal amanitas. Molecular dating through BEAST and biogeographic analyses with LAGRANGE and RASP indicated that lethal amanitas most likely originated in the Palaeotropics with the present crown group dated around 64.92 Mya in the early Paleocene, and the East Asia–eastern North America or Eurasia–North America–Central America disjunct distribution patterns were primarily established during the middle Oligocene to Miocene. The cryptic diversity found in this study indicates that the species diversity of lethal amanitas is strongly underestimated under the current taxonomy. The intercontinental sister species or sister groups relationships among East Asia and eastern North America or Eurasia–North America–Central America within lethal amanitas are best explained by the diversification model of Palaeotropical origin, dispersal via the Bering Land Bridge, followed by regional vicariance speciation resulting from climate change during the middle Oligocene to the present. These findings indicate the importance of both dispersal and vicariance in shaping the intercontinental distributions of these ectomycorrhizal fungi.
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.
Ophiocordyceps xuefengensis, a recently described species of Ophiocordyceps that is associated with the larvae of Phassus nodus (Hepialidae) in the living root or trunk of the medicinal plant Clerodendrum cyrtophyllum, is the largest known Cordyceps species and is recognized as a desirable alternative for natural Ophiocordyceps sinensis. This study investigated the main nucleosides and nucleobases in natural and cultured Ophiocordyceps xuefengensis. The contents of the nucleosides and nucleobases in the natural and cultured samples were determined by reverse phase HPLC. The highest concentration of adenosine was found in the natural fruit body and the cultured stroma, with almost no adenosine in the cadaver of Phassus nodus. The contents of adenine, guanosine, uridine and uracil in the cultured mycelium were significantly higher than those in the natural sample. Inosine was only detected in the natural samples. Thymidine and 2-deoxyadenosine were only found in the cadaver of Phassus nodus. Cordycepin was not detected in the five samples examined. These results suggested that the cultured mycelium and cultured stroma of Ophiocordyceps xuefengensis might be a promising substitute for natural O. xuefengensis.
Two new species of Phaeoclavulina (Gomphaceae, Gompales, Basidiomycota) from Hunan Province, China are distinguished on the basis of the morphological characters and molecular phylogenetic analyses. Phaeoclavulina aeruginea is characterized by basidiomata ramarioid, repeatedly branched, stipe yellowish brown, copper-green and blunt branch tips, and the context, turning wine red when bruised or exposed. Phaeoclavulina cinnamomea produces the cinnamon basidiomata, crowded branches, and large basidiospores with truncate (volcanic) spines, which is particularly rare in Phaeoclavulina. The two species are illustrated by drawings and photographs, including scanning electron micrographs. Their taxonomic distinctness was supported by the phylogenetic analyses of internal transcribed spacer (ITS) and nuclear ribosomal large subunit (nrLSU) sequence data. The ITS and nrLSU sequences newly generated in this study were deposited in GenBank. A key to Phaeoclavulina species in China is provided.
Two new species of Trechispora indigenous to southern China, T. laxa and T. tongdaoensis, are described and illustrated, and the first record of T. khokpasiensis in China is reported. Molecular phylogenetic analyses of the concatenated nuclear rDNA ITS1–5.8S–ITS2 and nuclear large subunit sequences supported the inclusion of the three species within the Trechispora clade, together with species formerly classified in Scytinopogon. The new species are similar in micromorphology to species of Trechispora (as traditionally circumscribed) but are distinguished by having coralloid basidiomata. A key to the known coralloid Trechispora species in China is provided.