The incorporation of molecular biological techniques and fungal systematics has brought about revolutionary changes in fungal taxonomy and phylogenetic studies. In the last two decades, a large number of new orders, families, genera and new species have been established, which has opened a new era in the study of fungal diversity, its origin and evolution. However, many important phylogenetic issues have not been solved, especially the phylogenetic relationships among many orders and families are still unclear. Subdivision is the mainstream trend of fungal systematics, so is the classification of wild edible mushrooms and toadstools. In recent years, more and more new taxa have been discovered. For example, in the ten years from 2010 to 2019, more than 1 240 new species of large fungi (including lichens) have been published in China. The 15 papers included in this special issue are part of the summary of the research work on wild edible fungi and toadstools in China, and have important scientific significance and application value for the utilization of fungal resources, and the prevention and treatment of mushroom poisoning.
The family Russulaceae includes a large number of edible species collected and consumed worldwide and some poisonous ones. The family, especially the genus Russula is notoriously difficult in taxonomy. Application of DNA data to the taxonomic studies updates the limits and concepts of its constituent genera and uncovers an increasing number of new species. This brings available names for identification of edible and poisonous species, but simultaneously causes confusion and inconvenience when using the new and amended names due to discordance between molecular and morphological evidences. Focusing on several important edible groups of Russulaceae, this paper reviews the most recent progresses in the taxonomy of Russulaceae, analyzes the data supporting the studies and gives comments on the taxonomic issues. The author concludes that morphological approach is more feasible in identifying edible or poisonous species if shared characters within a species complex are fully understood. Splitting taxonomy using only DNA data and describing new species with insufficient sampling and few changes in sequence data may have unpractical taxonomic outcomes. In the taxonomic practice of Lactarius and Russula, “low similarity in BLAST equal to new species” has a risk of producing synonyms. To achieve a thoroughly resolved taxonomy, full reference to historical documents and setting appropriate cutoffs when delimitating species by respecting the personality of each group is needed.
The genus Cortinarius is the largest genus of Agaricales with more than 2 000 species described, and some species contain fatal orellanine which can cause acute renal failure and lead to death. In this paper, the poisonous species, toxicosis clinical symptoms, detection, toxicity, toxicology and detoxification of orellanine as well as application of orellanine in the treatment of renal cancer are reviewed. The prospects in some hot research fields are discussed.
Deadly Amanita cyclic peptides are produced by some species in three genera of the order Agaricales, i.e., Amanita, Lepiota and Galerina. Statistically, over 90% of deadly mushroom poisoning cases are caused by the cyclic peptide toxins worldwide. Despite distant affinity, the three genera produce the same Amanita cyclic peptides, and they adopt a similar metabolic pathway for biosynthesis of the toxins, involving multiple biosynthetic genes and a special combinatorial mechanism. This review summarizes the advances in the related areas of biosynthesis of Amanita cyclic peptide toxins. Concerned difficult problems arisen in current studies are pointed out and future trend in the research field is prospected.
Closely related species of Russula virescens complex “qingtoujun” from markets of southwestern, central and eastern China were surveyed. Morphological features and ITS rDNA phylogenetic evidence indicate that “qingtoujun” are complex species having close affinity to R. virescens, intermix with R. viridicinnamomea, R. viridirubrolimbata and R. pseudocrustosa sp. nov. There are discrepancies in morphology and ITS phylogeny between the Chinese R. aff. virescens and European R. virescens and North American R. parvovirescens. The R. virescens species complex has a vast distribution in Asia and delimitation of species needs further studies.
Two new club fungi of Clavariadelphus (Clavariadelphaceae, Gomphales, Basidiomycota) from alpine temperate forests in southwestern China are substantiated based on morphological evidence and molecular phylogenetic analyses. Clavariadelphus aurantiacus is characterized by its turbinate, bright orange-yellow basidiomata with a sterile apex. Clavariadelphus tenuis has slender basidiomata and clampless hyphae. The two species are described in detail and illustrated with line drawings and photographs. Comparison between the new species and similar species is made. Phylogenetic relationships in Clavariadelphus are analyzed based on internal transcribed spacer rDNA sequences. A key to known Clavariadelphus species in China is provided.
Two smooth-spored species of Inocybe, I. muricellatoides and I. gansuensis, are described from Gansu Province, northwestern China based on morphological and molecular data. Detailed descriptions, line drawings, photographs and comparisons between affined species are presented. The nuclear ribosomal internal transcribed spacer region (ITS), a portion of the nuclear ribosomal large subunit (nLSU) and a portion of the nuclear second-largest subunit of RNA polymerase II (rpb2) gene of these species were sequenced and analyzed. Inocybe muricellatoides is characterized by ochraceous-squarrose pileus, fibrillose stipe, smooth basidiospores and thick-walled pleurocystidia. Inocybe gansuensis is characterized by robust basidiomata, large basidiospores and thick-walled pleurocystidia. Bayesian phylogenetic analysis based on LSU and rpb2 sequence data confirmed the distinctiveness of these species and correctness of their placement within Inocybe s. str.
Gyromitra venenata, a new poisonous species belonging to Gyromitra subgenus Gyromitra, is described from central and southwestern China on the basis of morphological data and phylogenetic evidence. Morphologically, the new species is very similar to G. esculenta. Nevertheless, G. venenata has well-differentiated ectal excipulum with a layer of palisade cells. The ectal excipulum of G. esculenta is not well differentiated from medullary excipulum. Moreover, the new species usually possesses longer stipe and is found on the ground in broad-leaved forests. In order to interpret the concept of G. esculenta consistently, the collection HMAS 21460, collected from France, is designated as an epitype of G. esculenta.
The “big-foot mushroom”, a well-known edible mushroom in Lüliang Mts. of Shanxi Province in North China, was described and illustrated as a new species, namely Clitopaxillus dabazi sp. nov. This species is similar and closely related to the European C. alexandri and C. fibulatus, but differs in having an earth brown to whitish grey-brown, hemispheric cap with a slightly involute margin, a robust clavate stipe and an agaric odor. Phylogenetic analyses based on multiple genes supported the establishment of this new species. This species occurs in autumn, and is widely distributed across Lüliang Mts., where it has been found among grasses under Picea or Larix trees in the northern parts while under Pinus or Quercus in the southern parts of the mountains. The specimens are deposited in Biology Department Herbarium, Capital Normal University (BJTC) in Beijing and Herbarium Institute of Edible Fungi, Shanxi Academy of Agricultural Science (HSA) in Taiyuan. In addition, a key to the known three species of Clitopaxillus is given.
A new genus with a new species, Tricholyophyllum brunneum, is described from southwestern China based on both morphological and molecular phylogenetic evidence. This genus differs phenotypically from the rest genera of the family by a trichodermal pileipellis, a discontinuous trichodermal stipitipellis, presence of cheilocystidia, and elongate to cylindrical basidiospores.
Based on morphology and phylogenetic evidence, a wild mushroom collected from Qilian Mountains Nature Reserve, northwestern China was identified as Pleurotus abieticola. The biological characteristics and cultivation conditions of this fungus were studied. The results showed that the optimal growth temperature of the mycelium was 25°C; the optimal pH of growth was 7.0; the optimal carbon source and nitrogen source were corn flour and soybean flour, respectively. The fruiting body could form in the substrate composed of cottonseed shell, sawdust and bran.
Twenty one poisonous Amanita species from South China were confirmed through literature survey and actual investigations, including seven lethal species causing acute liver failure, seven species causing acute renal failure, and seven species causing psychoneurological disorder. Statistics from 2000 to 2019 showed that there were a total of 45 poisoning cases causing toxicoses of 163 patients and 60 deaths, with mortality of 36.8% in South China. The poisoning cases mainly occurred from March to September, and most in March. Amanita exitialis was the “number one killer” in South China, causing about 70% of total cases of poisoning and death.
Mushroom poisoning has become an important food safety issue threating people’s health in China, wherein Chlorophyllum molybdites is accepted to be the most common toxic mushroom species. To prevent C. molybdites poisoning, it is crucial and urgent to reveal its spatial and temporal distribution patterns. Extensive and systematic collection of C. molybdites in China in 20 years during 1978 to 2020 demonstrated that C. molybdites appeared in 17 provinces and mainly concentrated in the tropical and subtropical areas and occasionally distributed in Northeast China (Heilongjiang and eastern Inner Mongolia), and there were hitherto no records in North and Northwest China. It was found that C. molybdites nearly occurred throughout the year in China from March to December, and prosperously from June to October. This species annually first appeared in tropical South China (Guangdong) in mid-spring, then spread to other tropical to subtropical areas of South, East, Central and Southwest China and was sustained to mid-autumn. From late autumn to early winter, its distribution areas was limited to tropical Southwest China (Mengla County of Yunnan). In temperate to cold temperate zones, C. molybdites only appeared in late summer to early fall in northeastern China.
The content of six cyclopeptides in different parts of fruiting body at three different development stages of Amanita exitialis collected from Shuangbai county, Chuxiong Prefecture of Yunnan Province was systematically detected and analyzed by reverse phase high-performance liquid chromatography. The results showed that Amanita exitialis contains α-amanitin, β-amanitin, phallisacin and phallacidin, but γ-amanitin and phalloidin were undetected. The total toxin concentrations gradually changed from growing stage (9.3mg/g), mature stage (7.5mg/g) to aged stage (6.5mg/g). However, the relative content of phallotoxins increased and amatoxins/phallotoxins ratio reduced from 2.6 at growing stage, 1.4 at mature stage to 0.9 at aged stage. In three different growth stages, concentrations of the four toxins were the highest in pileus, moderate in stipe, and the lowest in volva, while the relative content of phallotoxins increased successively in pileus, stipe and volva. The highest content of α-amanitin (7.4mg/g) and β-amanitin (3.1mg/g) were found in pileus in growing stage, but the highest content of phallisacin and phallacidin were in pileus in aged stage, being 2.8mg/g and 2.1mg/g respectively.
The chemical constituents and biological activities of the fruiting bodies of Lyophyllum decastes were studied. Fractionation of the crude extract by the modern chromatographic separation techniques afforded eight secondary metabolites, four of which were polyacetylene. The structures of those compounds were elucidated by nuclear magnetic resonance (NMR), mass spectrometry (MS) techniques as well as circular dichroism spectral (CD) and electron circular dichroism (ECD). The antioxidant activities of these isolated compounds were evaluated using cellular antioxidant activity (CAA) assay. Compounds 1-4 all showed antioxidant activity to a certain extent, of which compound 1 showed the strongest activity with EC50 (24.73±6.12)μmol/L. Polyacetylene compounds 1-4 were isolated from L. decastes for the first time, providing reference compounds for further HPLC-DAD analysis.
Ten new records of the genus Mycena found in Jilin and other ten provinces or autonomous regions of China were reported. They were M. aurantiidisca, M. flavoalba, and M. floridula of sect. Adonideae, M. heteracantha of sect. Amparoina, M. amygdalina of sect. Filipedes, M. zephirus of sect. Fragilipedes, M. hiemalis and M. speirea of sect. Hiemalis, and M. flos-nivium of sect. Mycena. The morphological descriptions, line drawings, and taxonomical discuss for each species are given. Ninety ITS sequences, including newly gene related and downloaded ones, were selected to infer the phylogenetic relationships among the samples from other parts of the world and those from China using Bayesian inference and Maximum likelihood analysis. Our molecular phylogenetic data confirmed the taxonomic treatments. Voucher specimens examined were deposited in the Herbarium of Mycology of Jilin Agricultural University (HMJAU).
