An updated molecular phylogeny and Chinese species diversity of Tricholomataceae (Agaricales)

Fungi of the Tricholomataceae are of great ecological and economic importance. Most species in this family are ectomycorrhizal fungi that play a crucial role in tree growth. Many species, such as Tricholoma matsutake and T. bakamatsutake, are highly regarded delicacies, while others, like T. highlandense and T. pardinum, are poisonous to humans. However, limited taxon sampling and insufficient molecular data have hindered our understanding of the species diversity of Tricholomataceae in many regions, including China. In this study, 371 specimens of Tricholomataceae from China were analysed using integrated approaches, including phylogenomic data, multi-gene phylogenetic evidence, morphological characteristics, and ecological features. Phylogenetic analysis of the concatenated dataset of nrLSU/ITS/nrSSU/RPB2 revealed that Tricholomataceae s. str. forms a monophyletic group, comprising 11 genera (Albomagister, Corneriella, Dennisiomyces, Dermoloma, Leucopaxillus, Neodermoloma, Porpoloma, Pseudobaeospora, Pseudoporpoloma, Pseudotricholoma, and Tricholoma). Among these, Tricholoma is the most species-rich genus within the family. Phylogenomic analysis utilizing 1,477 single-copy orthologous genes indicated that Tricholoma comprises five subgenera (subgen. Tricholoma, subgen. Pardinicutis, subgen. Sericeicutis, subgen. Terrea, and Melleum clade) and 15 section-level clades (sect. Tricholoma, sect. Fucata, sect. Genuina, sect. Matsutake, sect. Muscaria, sect. Rigida, sect. Pardinicutis, sect. Lasciva, sect. Sericella, sect. Atrosquamosa, sect. Terrea, Clades A, B, and C, and Melleum clade), with phylogenetic relationships among these clades fully resolved. Detailed morphological studies allowed for the identification of possible synapomorphies of Tricholoma and diagnostic characteristics for each subgenus and section. From China, 82 species of Tricholomataceae were documented, including 24 novel species and 58 known species from five genera. These findings were based on multi-gene analysis (ITS/RPB2/MCM7/EF1-α/mtSSU), ITS phylogenetic inference, morphological characteristics, and ecological data. Comprehensive descriptions, illustrations, and identification keys for these species are provided. Among the 82 species recognized in China, 52 were originally described from East Asia, while 30 originated from Europe or North America, suggesting that over 60% of the family’s species are probably endemic to (East) Asia.