Four new species of Russula from the Xizang Autonomous Region and other provinces of China.

Russula is the largest genus in the Russulales and is widespread throughout the world. Almost all Russula species are known to be ectomycorrhizal with high ecological and edible values, and some are lethal poisonous. In this study, four new species belonging to the subgenus Russula crown clade are identified based on morphological and phylogenetic evidence from the Xizang Autonomous Region and other provinces of China. Morphologically, Russula paragraveolens (sect. Polychromae, subsect. Xerampelinae) is mainly characterised by a cherry red to blood red pileus centre, a reddish orange pileus margin; R. pseudograveolens (sect. Polychromae, subsect. Xerampelinae) is characterised by a violet brown to brownish red pileus centre, a pale red to pastel red pileus margin and short basidia; R. shigatseensis (sect. Flavisiccantes, subsect. Lepidinae) is characterised by a brownish orange to madder red pileus centre, pinkish red pileus margin, and having lateral branches or branches of hyphal terminations in pileipellis; R. yadongensis (sect. Tenellae, subsect. Laricinae) is characterised by a dark purplish red pileus centre with brownish purple tints and having isolated to clustered spines of spore ornamentations. Their distinct taxonomic status is confirmed by the positions of the four new species in both the ITS and 4-locus (nucLSU, mtSSU, rpb2, tef1) phylogenetic trees.

Five New Species of Gymnopilus from Xizang Autonomous Region of China and Surrounding Areas.

The species of Gymnopilus (Hymenogastraceae, Agricales) are commonly recognized as wood-decaying fungi. Certain members of this genus have been identified as psilocybin-producing mushrooms. Gymnopilus exhibits a diverse range and has a global distribution. In this study, a total of seventy-eight specimens were gathered from ten provinces in China. A comprehensive molecular phylogenetic analysis was conducted, employing gene sequences including ITS, nrLSU, nrSSU, rpb1, rpb2, and tef1-α. Additionally, morphological examinations were also carried out. The phylogenetic topology of Gymnopilus from this study generally agreed with previous studies and facilitated the identification of all those specimens. As a result, eleven species, including five newly discovered ones named Gy. gyirongensis, Gy. variisporus, Gy. tomentosiceps, Gy. tenuibasidialis, and Gy. aurantipileatus, were recognized. Significantly, four of the five newly identified species are native to the Xizang Autonomous Region, emphasizing their specialization in this distinctive habitat. This research contributes to our comprehension of Gymnopilus diversity and lays the groundwork for the conservation and sustainable utilization of Gymnopilus resources.

Macrofungal Diversity and Distribution Patterns in the Primary Forests of the Shaluli Mountains.

The Shaluli Mountains are located in the southeastern part of the Tibetan Plateau at an elevation of 2500-5000 m. They are characterized by a typical vertical distribution of climate and vegetation and are considered a global biodiversity hotspot. We selected ten vegetation types at different elevation gradients representing distinct forests in the Shaluli Mountains to assess the macrofungal diversity, including subalpine shrub, Pinus spp., Populus spp., Pinus spp. and Quercus spp., Quercus spp., Abies spp., Picea spp. and Abies spp., Picea spp., Juniperus spp., and alpine meadow. In total, 1654 macrofungal specimens were collected. All specimens were distinguished by morphology and DNA barcoding, resulting in the identification of 766 species belonging to 177 genera in two phyla, eight classes, 22 orders, and 72 families. Macrofungal species composition varied widely among vegetation types, but ectomycorrhizal fungi were predominant. In this study, the analysis of observed species richness, the Chao1 diversity index, the invsimpson diversity index, and the Shannon diversity index revealed that the vegetation types with higher macrofungal alpha diversity in the Shaluli Mountains were composed of Abies, Picea, and Quercus. The vegetation types with lower macrofungal alpha diversity were subalpine shrub, Pinus spp., Juniperus spp., and alpine meadow. The results of curve-fitting regression analysis showed that macrofungal diversity in the Shaluli Mountains was closely related to elevation, with a trend of increasing and then decreasing with rising elevation. This distribution of diversity is consistent with the hump-shaped pattern. Constrained principal coordinate analysis based on Bray-Curtis distances indicated that macrofungal community composition was similar among vegetation types at similar elevations, while vegetation types with large differences in elevation differed significantly in macrofungal community composition. This suggests that large changes in elevation increase macrofungal community turnover. This study is the first investigation of the distribution pattern of macrofungal diversity under different vegetation types in high-altitude areas, providing a scientific basis for the conservation of macrofungal resources.

Four new species of Agaricus subgenus Spissicaules from China.

Agaricus subgenus Spissicaules is widely distributed in the world. In this study, 114 specimens were included in multigene phylogenetic analyses that allowed a better circumscription of the four sections in A. subg. Spissicaules. Three new species from China, A. brunneovariabilis, A. beijingensis, and A. planiceps, are described and placed in different sections. The invalidly described A. catenariocystidiosus is validated here as an additional new species. Comparisons between the sequences of the three closely related species A. thiersii, A. parasubrutilescens, and A. linzhiensis support the distinction between these three species despite the paraphyly of A. linzhiensis, which results from its high intraspecific variability with numerous heteromorphisms.

Molecular Evolution of Lysine Biosynthesis in Agaricomycetes.

As an indispensable essential amino acid in the human body, lysine is extremely rich in edible mushrooms. The α-aminoadipic acid (AAA) pathway is regarded as the biosynthetic pathway of lysine in higher fungal species in Agaricomycetes. However, there is no deep understanding about the molecular evolutionary relationship between lysine biosynthesis and species in Agaricomycetes. Herein, we analyzed the molecular evolution of lysine biosynthesis in Agaricomycetes. The phylogenetic relationships of 93 species in 34 families and nine orders in Agaricomycetes were constructed with six sequences of LSU, SSU, ITS (5.8 S), RPB1, RPB2, and EF1-α datasets, and then the phylogeny of enzymes involved in the AAA pathway were analyzed, especially homocitrate synthase (HCS), α-aminoadipate reductase (AAR), and saccharopine dehydrogenase (SDH). We found that the evolution of the AAA pathway of lysine biosynthesis is consistent with the evolution of species at the order level in Agaricomycetes. The conservation of primary, secondary, predicted tertiary structures, and substrate-binding sites of the enzymes of HCS, AAR, and SDH further exhibited the evolutionary conservation of lysine biosynthesis in Agaricomycetes. Our results provide a better understanding of the evolutionary conservation of the AAA pathway of lysine biosynthesis in Agaricomycetes.

A revision of Agaricus section Arvenses with nine new species from China.

Agaricus sect. Arvenses includes numerous species that are potential candidates for cultivation, and some have high nutritional and medicinal interests. Between 2012 and 2017, 147 specimens of A. sect. Arvenses were collected in China. For this study, nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), nuc 28S rDNA (28S), and translation elongation factor 1-alpha (tef1) sequences were used to assess species boundaries of these samples from China. Combined with morphological examination, we recognize 22 species of A. sect. Arvenses from China, of which 12 are known species, one is new record for China, and nine are proposed as new.

A new section and species of AgaricussubgenusPseudochitonia from Thailand.

A large species diversity has recently been discovered in the genus Agaricus. Six subgenera and 23 sections are now recognised. In this study, three specimens collected from Thailand, formed a monophyletic clade in subgenus Pseudochitonia, based on analyses of ITS sequence data. Further analyses, based on multi-gene sequence data (ITS, LSU, tef1-α), using BEAST, revealed that this clade originated 26.7 Ma. According to their distinct morphological characteristics, phylogenetic position and relatively old divergence time, a new section Cymbiformes is proposed and this section is represented by a new species A.angusticystidiatus. This new section is characterised by the strong iodoform odour of basidiomes and cymbiform basidiospores. Descriptions, colour photographs and illustrations are presented.

Tropic origins, a dispersal model for saprotrophic mushrooms in Agaricus section Minores with descriptions of sixteen new species.

Agaricus section Minores contains the richest species diversity within the genus. Its Phylogeny is firstly presented by a Maximum Likelihood tree generated through DNA sequences from four gene regions of 91 species. Furthermore, a molecular dating analysis is conducted used those sequences, and it provided the divergence times of the clades within section Minores. Study showed section Minores has a tropical origin. Four main dispersal routes are proposed: (1) species from South Asia migrated through the Tibetan Plateau and reached Europe ca. 9-13 Ma; (2) species from out of South Asia dispersed to Europe in the earlier time of ca. 22 Ma; (3) species from South Asia dispersed through North Asia to Alaska, and reached West America around ca. 9 Ma; and (4) species from South Asia dispersed south and reached Oceania by at least three invading events about ca. 9, 12 and 16-18 Ma respectively. Those routes excepting the second route coincide with those of ectomycorrhizal mushrooms. To know whether the second route existed in the saprotrophic mushrooms requires further studies, and the fourth route may explain why the secotioid species occurring in Australia are morphologically similar but cluster in different phylogenetic clades. This study also demonstrates a great biodiversity of A. section Minores in China. Sixteen new species and three new records are introduced from China with morphological descriptions, illustrations, color photographs and phylogenetic analyses.