Global phylogeny of the Shiitake mushroom and related Lentinula species uncovers novel diversity and suggests an origin in the Neotropics

Taxonomy and phylogeny of Panus (Polyporales, Panaceae) in China and its relationship with allies

Panus is a typical wood-rotting fungi, which plays considerable roles in ecosystems and has significant economic value. The genus Panus currently consists of more than 100 species; however, only eight species have been reported from China. This study aims to distinguish and describe two novel species from the Panussimilis complex, namely Panusminisporus and Panusbaishanzuensis, one new record species from Zhejiang Province, Panussimilis and three common species, Panusconchatus, Panusneostrigosus and Panusrudis, based on detailed morphological and phylogenetic studies, relying on Chinese specimens. Panusminisporus is characterised by its reddish-brown pileus, decurrent lamellae with cross-veins, slender stipe, smaller basidiospores, wider generative hyphae and absence of sclerocystidia. Panusbaishanzuensis is featured by its pileus with concentric and darker ring zone, decurrent lamellae with cross-veins, shorter stipe, longer basidiospores, diverse and shorter cheilocystidia and smaller sclerocystidia. Internal transcribed spacer (ITS) regions, large subunit nuclear ribosomal RNA gene (nLSU) and translation elongation factor 1-α gene (tef-1α) were employed to perform a thorough phylogenetic analysis for genus Panus and related genera, using Bayesian Inference and Maximum Likelihood analysis. The results indicate that Panusminisporus and Panusbaishanzuensis form two independent clades within the Panussimilis complex themselves. Detailed descriptions, taxonomic notes, illustrations etc. were provided. In addition, a key to the reported species of Panus from China is also provided.

Global phylogeographical distribution of Gloeoporus dichrous

Phylogeographic analyses are efficient in ecological and evolutionary studies to discover the origin of a lineage, its dispersal routes, and the divergence of ancestral traits. Studies on widespread wood-decay fungi have revealed the phylogenetic division of several polypores based on geographical distribution. In this study, specimens of Gloeoporus dichrous, a cosmopolitan polypore species, were collected globally and analyzed for their geographic distribution. Multi-marker Bayesian molecular clock and haplotype analyses revealed a clear division of G. dichrous populations by continent. The species diverged from its neighboring clades 10.3 (16.0-5.6) million years ago, with Asian and North American populations at the center of divergence. Possible dispersal mechanisms and pathways are predicted and discussed based on the evaluated transfer routes. The biogeography of G. dichrous analyzed in this study represents a fraction of the polypore evolution and may advance the understanding of the overall evolution of wood-decay fungi.

Comparative structural analysis on the mitochondrial DNAs from various strains of Lentinula edodes

The evolution of mitochondria through variations in mitochondrial DNA (mtDNA) is one of the intriguing questions in eukaryotic cells. In order to assess the causes of the variations in mitochondria, the mtDNAs of the 21 strains of Lentinula edodes were assembled for this study, and analyzed together with four published mtDNA sequences. The mtDNAs were within the sizes of 117 kb ~ 122 kb. The gene number was observed consistent except for two mtDNAs, which carry a duplicated trnG1-trnG2 unit or a putative gene deletion. The size variation was largely attributed to the number of introns, repeated sequences, transposable elements (TEs), and plasmid-related sequences. Intron loss and gain were found from cox1, rnl, and rns of three mtDNAs. Loss of two introns in cox1 of KY217797.1 reduced its size by 2.7 kb, making it the smallest cox1 gene (8.4 kb) among the cox1s of the 25 mtDNAs, whereas gain of a Group II intron (2.65 kb) and loss of a Group I intron (1.7 kb) in cox1 of MF774813.1 resulted in the longest cox1 (12 kb). In rnl of L. edodes, we discovered four intron insertion consensus sequences which were unique to basidiomycetes but not ascomycetes. Differential incorporation of introns was the primary cause of the rnl size polymorphism. Homing endonucleases (HEGs) were suggestively involved in the mobilization of the introns because all of the introns have HEG genes of the LAGRIDADG or GIY-YIG families with the conserved HEG cleavage sites. TEs contributed to 11.04% of the mtDNA size in average, of which 7.08% was LTR-retrotransposon and 3.96% was DNA transposon, whereas the repeated sequences covered 4.6% of the mtDNA. The repeat numbers were variable in a strain-dependent manner. Both the TEs and repeated sequences were mostly found in the intronic and intergenic regions. Lastly, two major deletions were found in the plasmid-related sequence regions (pol2-pol3 and pol1-atp8) in the five mtDNAs. Particularly, the 6.8 kb-long deletion at pol2-pol3 region made MF774813.1 the shortest mtDNA of all. Our results demonstrate that mtDNA is a dynamic molecule that persistently evolves over a short period of time by insertion/deletion and repetition of DNA segments at the strain level.

What is the correct scientific name for “Fuling” medicinal mushroom?

In recent years, the scientific names of many cultivated and well-known medicinal fungal species have been changed. However, the results of taxonomic and nomenclature works on these economically important fungi are often overlooked or ignored in applied researches. The incorrect use of scientific names may cause uncertainty in research and in the global medicinal mushroom market. In this paper, we briefly review the current taxonomy and nomenclature of “Fuling” medicinal mushroom and make a proposal for biochemists, pharmacists and businessmen on the correct use of scientific names related to this species. Based on the recent taxonomic results and nomenclatural proposals, the use of the names Wolfiporia extensa, W. cocos and especially Poria cocos for the “Fuling” mushroom are incorrect and misleading; therefore, the acceptance of the names Pachyma hoelen or Wolfiporia hoelen is recommended.