Nian-Kai Zeng

Mushrooms in the basidiomycete family Boletaceae are ecologically and economically very important. However, due to the morphological complexity and the limited phylogenetic information on the various species and genera of this fungal family, our understanding of its systematics and evolution remains rudimentary. In this study, DNA sequences of four genes (nrLSU, tef1-α, rpb1, and rpb2) were newly obtained from ca. 200 representative specimens of Boletaceae. Our phylogenetic analyses revealed seven major clades at the subfamily level, namely Austroboletoideae, Boletoideae, Chalciporoideae, Leccinoideae, Xerocomoideae, Zangioideae, and the Pulveroboletus Group. In addition, 59 genus-level clades were identified, of which 22 were uncovered for the first time. These 22 clades were mainly placed in Boletoideae and the Pulveroboletus Group. The results further indicated that the characters frequently used in the morphology-based taxonomy of Boletaceae, such as basidiospore ornamentation, the form of the basidioma, and the stuffed pores each had multiple origins within the family, suggesting that the use of such features for high-level classification of Boletaceae should be de-emphasized and combined with other characters.

The wild gourmet mushroom Boletus edulis and its close allies are of significant ecological and economic importance. They are found throughout the Northern Hemisphere, but despite their ubiquity there are still many unresolved issues with regard to the taxonomy, systematics and biogeography of this group of mushrooms. Most phylogenetic studies of Boletus so far have characterized samples from North America and Europe and little information is available on samples from other areas, including the ecologically and geographically diverse regions of China. Here we analyzed DNA sequence variation in three gene markers from samples of these mushrooms from across China and compared our findings with those from other representative regions. Our results revealed fifteen novel phylogenetic species (about one-third of the known species) and a newly identified lineage represented by Boletus sp. HKAS71346 from tropical Asia. The phylogenetic analyses support eastern Asia as the center of diversity for the porcini sensu stricto clade. Within this clade, B. edulis is the only known holarctic species. The majority of the other phylogenetic species are geographically restricted in their distributions. Furthermore, molecular dating and geological evidence suggest that this group of mushrooms originated during the Eocene in eastern Asia, followed by dispersal to and subsequent speciation in other parts of Asia, Europe, and the Americas from the middle Miocene through the early Pliocene. In contrast to the ancient dispersal of porcini in the strict sense in the Northern Hemisphere, the occurrence of B. reticulatus and B. edulis sensu lato in the Southern Hemisphere was probably due to recent human-mediated introductions.

Species of the genus Phylloporus in China were investigated based on morphology and molecular phylogenetic analysis of a three-locus (nrLSU, ITS and tef-1a) DNA sequence dataset. Twenty-one phylogenetic species were recognized among the studied collections. Seven of them are described as new: P. brunneiceps, P. imbricatus, P. maculatus, P. pachycystidiatus, P. rubeolus, P. rubrosquamosus, and P. yunnanensis. In addition, four of them correspond with the previous morphology-based taxa: P. bellus, P. luxiensis, P. parvisporus, and P. rufescens. The remaining ten phylogenetic species were not described due to the paucity of the materials. A key to the Chinese morphologically recognizable taxa was provided. A preliminary biogeographical analysis showed that (1) Pylloporus species in East Asia and Southeast Asia are mostly closely related, (2) species pairs or closely related species of Phylloporus between East Asia and North/Central America are relatively common, and (3) the biogeographic relationship of Phylloporus between East Asia and Europe was supported by only a single species pair. Unexpectedly, no taxa common either to both Europe and East Asia, or to both East Asia and North/Central America, were uncovered. Clades look to have taxa from both sides of the Pacific and Europe/Asia though.

Based on our previous molecular phylogenetic analyses, four new genera are described, namely Baorangia, Lanmaoa, Parvixerocomus, and Rugiboletus, and one known genus, Neoboletus, is re-delimitated. Four new species and nine new combinations are proposed. Morphological characters of each genus and related eleven species are described and illustrated. Most of species in the genera described from southwestern China are wild edible mushrooms and can be found in free markets.