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.

Structure Analysis of the MatA Locus of Sexual Compatibility in the Edible Mushroom Pleurotus ostreatus

The edible oyster mushroom Pleurotus ostreatus is one of the most cultivated species worldwide. Morphogenesis associated with the maturation of fruit bodies is controlled by two unlinked loci of sexual compatibility matA and matB with multiple alleles (tetrapolar system of sexual compatibility). Quantitative analysis of the alleles of mating compatibility loci in 17 natural isolates collected in the Moscow region was performed in mon-mon (monokaryons-monokaryon) and di-mon (dikaryon-monokaryon) crossings. Four monokaryotic testers strains which were heteroallelic at both mating type loci were obtained for each of the five natural mushroom isolates by using original technique of sterile spore prints on Petri dishes and mon-mon crossing. Twelve natural isolates were crossed via di-mon mating with the four monokaryotic testers M-38. Genetic analysis of the alleles of sexual compatibility loci in 17 natural isolates revealed multiple alleles at both loci: at least ten alleles at matA locus and eight alleles at matB locus. Structural organization analysis of the matA locus was performed in silico for homokaryotic strains PC9 and PC15 based on the whole-genome sequencing data available at DOE Joint Genome Institute. The matA locus has an extremely divergent structure: there are one copy of the homeodomain gene hd1 and one copy of the hd2 gene in the PC9 strain, whereas the matA locus of the PC15 strain is composed by two copies of hd1.1 and hd1.2 genes (class HD1 homeodomain proteins) and one copy of hd2 gene (class HD2 proteins). Comprehensive analysis of amino acid sequences of HD1 and HD2 homeodomain proteins demonstrated that the proteins have a globular structure with the nuclear localization and contain a variable N-terminus and a more conserved DNA-binding domain with a specific conserved motif  WFXNXR in the third ɑ-helix. The results suggest that multiple alleles of the matA locus of sexual compatibility in basidiomycete fungi is achieved due to both different copy number of the coding hd genes within the locus and the variability of the coding gene sequences.

A review of the therapeutic and biological effects of edible and wild mushrooms

Throughout history, mushrooms have occupied an inseparable part of the diet in many countries. Mushrooms are considered a rich source of phytonutrients such as polysaccharides, dietary fibers, and other micronutrients, in addition to various essential amino acids, which are building blocks of vital proteins. In general, mushrooms offer a wide range of health benefits with a large spectrum of pharmacological properties, including antidiabetic, antioxidative, antiviral, antibacterial, osteoprotective, nephroprotective, hepatoprotective, etc. Both wild edible and medicinal mushrooms possess strong therapeutic and biological activities, which are evident from their in vivo and in vitro assays. The multifunctional activities of the mushroom extracts and the targeted potential of each of the compounds in the extracts have a broad range of applications, especially in the healing and repair of various organs and cells in humans. Owing to the presence of the aforementioned properties and rich phytocomposition, mushrooms are being used in the production of nutraceuticals and pharmaceuticals. This review aims to provide a clear insight on the commercially cultivated, wild edible, and medicinal mushrooms with comprehensive information on their phytochemical constituents and properties as part of food and medicine for futuristic exploitation. Future outlook and prospective challenges associated with the cultivation and processing of these medicinal mushrooms as functional foods are also discussed.

Toxic Potential of Traditionally Consumed Mushroom Species-A Controversial Continuum with Many Unanswered Questions

Mushroom poisonings remain a significant cause of emergency medicine. While there are well-known species, such as Amanita phalloides, causing life-threatening poisonings, there is also accumulating evidence of poisonings related to species that have been considered edible and are traditionally consumed. In particular, the Tricholoma equestre group was reported to cause myotoxicity. In addition, particular wild mushrooms that are traditionally consumed especially in Asia and Eastern Europe have been subject to suspicion due to possible mutagenicity. Hitherto, the causative agents of these effects often remain to be determined, and toxicity studies have yielded contradictory results. Due to this, there is no consensus about the safety of these species. The issue is further complicated by difficulties in species identification and other possible sources of toxicity, such as microbiological contamination during storage, leading to sometimes opposite conclusions about the edibility of a species. This review focuses on existing data about these types of mushroom poisonings, including the still sparse knowledge about the causative chemical agents. In addition, the aim is to initiate a meta-discussion about the issue and to give some suggestions about how to approach the situation from the viewpoint of the collector, the researcher, and the practicing physician.

The ligninolytic peroxidases in the genus Pleurotus: divergence in activities, expression, and potential applications

Mushrooms of the genus Pleurotus are comprised of cultivated edible ligninolytic fungi with medicinal properties and a wide array of biotechnological and environmental applications. Like other white-rot fungi (WRF), they are able to grow on a variety of lignocellulosic biomass substrates and degrade both natural and anthropogenic aromatic compounds. This is due to the presence of the non-specific oxidative enzymatic systems, which are mainly consisted of lacasses, versatile peroxidases (VPs), and short manganese peroxidases (short-MnPs). Additional, less studied, peroxidase are dye-decolorizing peroxidases (DyPs) and heme-thiolate peroxidases (HTPs). During the past two decades, substantial information has accumulated concerning the biochemistry, structure and function of the Pleurotus ligninolytic peroxidases, which are considered to play a key role in many biodegradation processes. The production of these enzymes is dependent on growth media composition, pH, and temperature as well as the growth phase of the fungus. Mn(2+) concentration differentially affects the expression of the different genes. It also severs as a preferred substrate for these preoxidases. Recently, sequencing of the Pleurotus ostreatus genome was completed, and a comprehensive picture of the ligninolytic peroxidase gene family, consisting of three VPs and six short-MnPs, has been established. Similar enzymes were also discovered and studied in other Pleurotus species. In addition, progress has been made in the development of molecular tools for targeted gene replacement, RNAi-based gene silencing and overexpression of genes of interest. These advances increase the fundamental understanding of the ligninolytic system and provide the opportunity for harnessing the unique attributes of these WRF for applied purposes.

Molecular divergence and species delimitation of the cultivated oyster mushrooms: integration of IGS1 and ITS

Identification of edible mushrooms particularly Pleurotus genus has been restricted due to various obstacles. The present study attempted to use the combination of two variable regions of IGS1 and ITS for classifying the economically cultivated Pleurotus species. Integration of the two regions proved a high ability that not only could clearly distinguish the species but also served sufficient intraspecies variation. Phylogenetic tree (IGS1+ITS) showed seven distinct clades, each clade belonging to a separate species group. Moreover, the species differentiation was tested by AMOVA and the results were reconfirmed by presenting appropriate amounts of divergence (91.82% among and 8.18% within the species). In spite of achieving a proper classification of species by combination of IGS1 and ITS sequences, the phylogenetic tree showed the misclassification of the species of P. nebrodensis and P. eryngii var. ferulae with other strains of P. eryngii. However, the constructed median joining (MJ) network could not only differentiate between these species but also offer a profound perception of the species' evolutionary process. Eventually, due to the sufficient variation among and within species, distinct sequences, simple amplification, and location between ideal conserved ribosomal genes, the integration of IGS1 and ITS sequences is recommended as a desirable DNA barcode.