New Insights into the Taxonomy of the Genus Cantharellus in China: Epityfication of C. yunnanensis W.F. Chiu and the First Record of C. cibarius Fr

Neuroprotection of low-molecular-weight galactan obtained from Cantharellus cibarius Fr. against Alzheimer's disease

The large molecular weight of polysaccharides limits their absorption and utilization by organisms, affecting their biological activities. In this study, we purified α-1,6-galactan from Cantharellus cibarius Fr. (chanterelle) and reduced its molecular weight from approximately 20 kDa to 5 kDa (named CCP) to increase its solubility and absorption. In APP/PS1 mice, CCP improved both spatial and non-spatial memory loss in Alzheimer's disease (AD) mice, as confirmed by the Morris water maze, step-down, step-through, and novel object recognition tests, and dampened the deposition of amyloid-β plaques, as assessed by immunohistochemical analysis. Proteomic analysis suggested that the neuroprotective effects of CCP are related to anti-neuroinflammation. Immunofluorescence analysis and western blotting confirmed that CCP attenuated AD-like symptoms partly by inhibiting neuroinflammation, which was related to the blocking of complement component 3. Our study provides theoretical support and experimental evidence for the future application of chanterelle-extracted polysaccharides in AD treatment, promoting the modern development of traditional medicines originating from natural polysaccharides.

Extraction, Characterization, and In Vitro Hypoglycemic Activity of a Neutral Polysaccharide from the New Medicinal Mushroom Cantharellus yunnanensis (Agaricomycetes)

Polysaccharides serve as promising ingredients for health-beneficial functional foods, while there were no investigations into the structural characterizations and bioactivities of an edible mushroom Cantharellus yunnanensis. In the study, crude polysaccharides from this mushroom were extracted by hot water and isolated by ethanol precipitation. Then, a neutral polysaccharide (named CY-1) was purified from the crude polysaccharide by deproteinization with Sevag reagent, decolorization with a kind of macroporous adsorption resin SP-825, DEAE-52 cellulose column chromatography and dialysis. The physicochemical properties of CY-1 were characterized by UV, IR, SEM, NMR, and HPLC analyses. Structural characterizations revealed that CY-1 is a homogeneous heteropolysaccharide with an average molecular weight of 3.06 × 104 Da. CY-1 exhibited a honeycomb structure with an irregular branching shape, and it was composed of mannose, glucose, fucose, xylose, arabinose, galactose, rhamnose, and glucuronic acid, with molar fractions of 54.83%, 25.11%, 10.28% 4.53%, 2.12%, 1.64%, 0.83%, and 0.64%, respectively. In vitro hypoglycemic tests showed that CY-1 had an inhibitory effect on α-glucosidase. In addition, CY-1 of 160 µg/mL promoted glucose consumption in normal HepG2 cells. These results suggested that CY-1 may be a potential hypoglycemic agent.

Morphological and Phylogenetic Evidences Reveal Four New Species of Cantharellus Subgenus Cantharellus (Hydnaceae, Cantharellales) From China

Species of Cantharellus subgenus Cantharellus are interesting and important for their mycorrhizal properties, medicinal values, and edibility. In China, there are many undescribed species of the subgenus. In this study, four new species of subg. Cantharellus, viz. Cantharellus albopileatus, Cantharellus chuiweifanii, Cantharellus pinetorus, and Cantharellus ravus from Hainan and Hunan Provinces, respectively, were described based on morphological and phylogenetic evidence as a contribution to the knowledge of the species diversity in China. Detailed descriptions, color photographs of fresh basidiomata, and line drawings of microstructures of these four new species are presented as well as comparisons with related species.

Diversity of Cantharellus (Cantharellales, Basidiomycota) in China with Description of Some New Species and New Records

Cantharellus is a well-known genus of edible mushrooms, belonging to the family Hydnaceae in the class Agaricomycetes. In this study, a phylogenetic overview of Cantharellus subg. Cinnabarinus and C. subg. Parvocantharellus in China is carried out with the description of four new species. Species description are based on morphological characters of basidiomata and phylogenetic analyses of multi-locus dataset of 28S + tef1 + rpb2. Among the new species, two species, C. chrysanthus and C. sinocinnabarinus, belong to C. subg. Cinnabarinus and two new species, C. convexus and C. neopersicinus, belong to C. subg. Parvocantharellus. Species delimitation characters of the new taxa are compared with closely related species. In addition, three new records of Cantharellus are reported for China: C. albovenosus and C. citrinus of subg. Cinnabarinus and C. koreanus of subg. Parvocantharellus. A key to the species of subg. Cinnabarinus in China was provided.

A phylogenetic overview of the Hydnaceae (Cantharellales, Basidiomycota) with new taxa from China

The family Hydnaceae (Cantharellales, Basidiomycota) is a group of fungi found worldwide which exhibit stichic nuclear division. The group is highly diverse in morphology, ecology, and phylogeny, and includes some edible species which are popular all over the world. Traditionally, Hydnaceae together with Cantharellaceae, Clavulinaceae and Sistotremataceae are four families in the Cantharellales. The four families were combined and redefined as "Hydnaceae", however, a comprehensive phylogeny based on multiple-marker dataset for the entire Hydnaceae sensu stricto is still lacking and the delimitation is also unclear. We inferred Maximum Likelihood and Bayesian phylogenies for the family Hydnaceae from the data of five DNA regions: the large subunit of nuclear ribosomal RNA gene (nLSU), the internal transcribed spacer regions (ITS), the mitochondrial small subunit rDNA gene (mtSSU), the second largest subunit of RNA polymerase II (RPB2) and the translation elongation factor 1-alpha gene (TEF1). We also produced three more phylogenetic trees for Cantharellus based on 5.8S, nLSU, mtSSU, RPB2 and TEF1, Craterellus and Hydnum both based on the combined nLSU and ITS. This study has reproduced the status of Hydnaceae in the order Cantharellales, and phylogenetically confirmed seventeen genera in Hydnaceae. Twenty nine new taxa or synonyms are described, revealed, proposed, or reported, including eight new subgenera (Cantharellus subgenus Magnus, Craterellus subgenus Cariosi, subg. Craterellus, subg. Imperforati, subg. Lamelles, subg. Longibasidiosi, subg. Ovoidei, and Hydnum subgenus Brevispina); seventeen new species (Ca. laevihymeninus, Ca. magnus, Ca. subminor, Cr. badiogriseus, Cr. croceialbus, Cr. macrosporus, Cr. squamatus, H. brevispinum, H. flabellatum, H. flavidocanum, H. longibasidium, H. pallidocroceum, H. pallidomarginatum, H. sphaericum, H. tangerinum, H. tenuistipitum and H. ventricosum); two synonyms (Ca. anzutake and Ca. tuberculosporus as Ca. yunnanensis), and two newly recorded species (H. albomagnum and H. minum). The distinguishing characters of the new species and subgenera as well as their allied taxa are discussed in the notes which follow them. The delimitation and diversity in morphology, ecology, and phylogeny of Hydnaceae is discussed. Notes of seventeen genera which are phylogenetically accepted in Hydnaceae by this study and a key to the genera in Hydnaceae are provided.

Multigene Phylogeny and Morphology Reveal Unexpectedly High Number of New Species of Cantharellus Subgenus Parvocantharellus (Hydnaceae, Cantharellales) in China

The genus Cantharellus, commonly known as chanterelles, has recently been divided into six subgenera; however, wider sampling approaches are needed to clarify the relationships within and between these groups. A phylogenetic overview of Cantharellus subgenus Parvocantharellus in China was inferred based on the large subunit nuclear ribosomal RNA gene (nrLSU), the DNA-directed RNA polymerase II subunit 2 (rpb2), and the transcription elongation factor 1-alpha (tef1). A total of nine species from China were assigned to the subgenus, including seven novel species, namely Cantharellusaurantinus, C. austrosinensis, C. galbanus, C. luteolus, C. luteovirens, C. minioalbus, and C. sinominior, and two known species, namely C. albus and C. zangii. The detailed descriptions and illustrations were provided based on the newly obtained data, with the comparisons to closely related species. C. zangii was restudied based on the paratype specimens and multiple new collections from the type locality. Futhermore, the Indian species C. sikkimensis was identified as a synonym of C. zangii based on the morphological and molecular analyses. A key to the Chinese species belonging to the subg. Parvocantharellus is also provided.

Evidence for Persistent Heteroplasmy and Ancient Recombination in the Mitochondrial Genomes of the Edible Yellow Chanterelles From Southwestern China and Europe

Mitochondrial genes and genomes have patterns of inheritance that are distinctly different from those of nuclear genes and genomes. In nature, the mitochondrial genomes in eukaryotes are generally considered non-recombining and homoplasmic. If heteroplasmy and recombination exist, they are typically very limited in both space and time. Here we show that mitochondrial heteroplasmy and recombination may not be limited to a specific population nor exit only transiently in the basidiomycete Cantharellus cibarius and related species. These edible yellow chanterelles are an ecologically very important group of fungi and among the most prominent wild edible mushrooms in the Northern Hemisphere. At present, very little is known about the genetics and population biology of these fungia cross large geographical distances. Our study here analyzed a total of 363 specimens of edible yellow chanterelles from 24 geographic locations in Yunnan in southwestern China and six geographic locations in five countries in Europe. For each mushroom sample, we obtained the DNA sequences at two genes, one in the nuclear genome and one in the mitochondrial genome. Our analyses of the nuclear gene, translation elongation factor 1-alpha (tef-1) and the DNA barcode of C. cibarius and related species, suggested these samples belong to four known species and five potential new species. Interestingly, analyses of the mitochondrial ATP synthase subunit 6 (atp6) gene fragment revealed evidence of heteroplasmy in two geographic samples in Yunnan and recombination within the two new putative species in Yunnan. Specifically, all four possible haplotypes at two polymorphic nucleotide sites within the mitochondrial atp6 gene were found distributed across several geographic locations in Yunnan. Furthermore, these four haplotypes were broadly distributed across multiple phylogenetic clades constructed based on nuclear tef-1 sequences. Our results suggest that heteroplasmy and mitochondrial recombination might have happened repeatedly during the evolution of the yellow chanterelles. Together, our results suggest that the edible yellow chanterelles represent an excellent system from which to study the evolution of mitochondrial-nuclear genome relationships.

Exploring the Species Diversity of Edible Mushrooms in Yunnan, Southwestern China, by DNA Barcoding

Yunnan Province, China, is famous for its abundant wild edible mushroom diversity and a rich source of the world's wild mushroom trade markets. However, much remains unknown about the diversity of edible mushrooms, including the number of wild edible mushroom species and their distributions. In this study, we collected and analyzed 3585 mushroom samples from wild mushroom markets in 35 counties across Yunnan Province from 2010 to 2019. Among these samples, we successfully obtained the DNA barcode sequences from 2198 samples. Sequence comparisons revealed that these 2198 samples likely belonged to 159 known species in 56 different genera, 31 families, 11 orders, 2 classes, and 2 phyla. Significantly, 51.13% of these samples had sequence similarities to known species at lower than 97%, likely representing new taxa. Further phylogenetic analyses on several common mushroom groups including 1536 internal transcribed spacer (ITS) sequences suggested the existence of 20 new (cryptic) species in these groups. The extensive new and cryptic species diversity in wild mushroom markets in Yunnan calls for greater attention for the conservation and utilization of these resources. Our results on both the distinct barcode sequences and the distributions of these sequences should facilitate new mushroom species discovery and forensic authentication of high-valued mushrooms and contribute to the scientific inventory for the management of wild mushroom markets.