Bang Feng

DNA Sequence Analyses Reveal Abundant Diversity, Endemism and Evidence for Asian Origin of the Porcini Mushrooms

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.

Molecular phylogenetic analyses redefine seven major clades and reveal 22 new generic clades in the fungal family Boletaceae

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.

Zangia, a new genus of Boletaceae supported by molecular and morphological evidence

A new distinct genus of Boletales, Zangia, with phenotypic similarities to the genus Tylopilus, is proposed based on molecular and morphological data. The monophyly of Zangia was highly supported using two nuclear and three mitochondrial genes based on Maximum Parsimony, Maximum Likelihood and Bayesian analyses. Morphologically, Zangia is distinguished from other boletoid lineages by its combination of rugose pileus, pinkish to pink hymenophore, pink to pinkish brown spore deposit, pink scabrous squamules on the stipe, chrome yellow to golden yellow stipe base, chrome yellow to golden yellow mycelia on the base of the stipe, ixohyphoepithelium pileipellis, glabrous spores and bluish colour changes in the stipe in some species. Geographically, Zangia is currently only known from southern, southeastern and southwestern China under forests dominated by Fagaceae mixed with Pinaceae. Six species, including 4 new ones and 2 new combinations, are fully documented with taxonomic descriptions and illustrations. A key to the species in Zangia is provided. It is suggested that some of the species might have started diverging from each other relatively recently with the uplifts of the eastern Himalayas and Hengduan Mountains, and both the mycorrhizal host specificity or preference and geographic separation could contribute to their ongoing divergence.

Borofutus, a new genus of Boletaceae from tropical Asia: phylogeny, morphology and taxonomy

A new monotypic genus in the Boletaceae, Borofutus, typified by B. dhakanus, is described using morphological and molecular evidence. This is a putatively ectomycorrhizal fungus associated with Shorea robusta. Borofutus is characterized by the combination of the following characters: basidiomata small to medium-sized; pileus grayish brown to cocoa brown; hymenophore subdecurrent, cream then golden brown, with broad, nearly hexagonal pores; basidiospores purple to purplish red in H2O, ornamented with irregular to regular shallow pits; cystidia lageniform, thick-walled. Borofutus is sister to Spongiforma in molecular phylogenetic analyses using DNA nucleotide sequences of single or multiple loci. A description, line drawings, phylogenetic placement and comparison with allied taxa are presented herein.

What is the Chinese “Lingzhi”? – a taxonomic mini-review

“Lingzhi” is a fungus found in China for about 2000 years, renowned for its immense values in traditional Chinese medicine and culture. This fungus was generally assigned to Ganoderma lucidum, a species originally described from the UK. In the mid-nineties of the twentieth century, molecular phylogenetic analyses indicated that collections named G. lucidum in East Asia were in most cases not conspecific with G. lucidum found in Europe. However, the scientific name for the “lingzhi” found in China remained unclarified ever since. To clarify the identity of this fungus, two groups of Chinese mycologists have simultaneously gathered morphological and molecular evidence. One group concluded that “lingzhi” belonged to G. sichuanense, a species which was collected from Sichuan, a province in southwestern China, while the other group stated that the “lingzhi” is an undescribed species and, thus, named it as G. lingzhi. Our molecular phylogenetic evidence showed that G. lucidum s. str. occurs not only in northwestern and northeastern China but also in the highlands of southwestern China, where it has been commercially cultivated. In other words, both G. lucidum s. str. and G. lingzhi occur in natural environments in China, where they have been cultivated. Due to the phenotypic plasticity and morphological stasis, DNA sequence data play a vital role in characterizing the species within the G. lucidum-complex. Because the internal transcribed spacer (ITS) sequence has been successfully generated only once from the holotype of G. sichuanense, it suggests that the DNA in the holotype might have been largely digested. To settle the disputation and to clarify the relationships and taxonomic issues among G. lingzhi, G. sichuanense, G. sinense and other species in the complex, an epitype for G. sichuanense and for G. sinense from their type locality should be selected , and nucleotide sequences of more informative DNA markers should be used to delimit the species in the complex in the near future. In view of its economic, medicinal and cultural importance, the widely cultivated G. lingzhi is nominated as the fungus of the year (2013) for the journal Mycology.

Molecular phylogeny and taxonomy of the genus Veloporphyrellus

Veloporphyrellus is a genus known from North and Central America, southeastern Asia, and Africa. Because species of this genus are phenotypically similar to some taxa in several genera, such as Boletellus, Leccinum, Strobilomyces, Suillus and Tylopilus s.l. belonging to Boletales, its phylogenetic disposition has never been addressed. We analyzed four DNA regions, the nuclear ribosomal LSU and tef-1α, and the mitochondrial mtSSU and atp6 genes, to investigate the phylogenetic disposition of Veloporphyrellus. Although the monophyly of the genus and its systematic placement within the Boletaceae was well supported, its relationship to other genera was not resolved. Morphologically Veloporphyrellus is distinguished from other boletoid genera by the combination of the pinkish or grayish pink hymenophore, the membranous veil hanging on the pilea margin, the trichoderm-like pileus covering and the smooth basidiospores. Five species, including two new species and two new combinations, are described and illustrated. A key to the species of Veloporphyrellus also is provided.

Genetic Diversity of Dahongjun, the Commercially Important "Big Red Mushroom'' from Southern China

Background In southern China, a wild ectomycorrhizal mushroom commonly called “Dahongjun” or “Big Red Mushroom” by the local residents, has been harvested, consumed, and/or exported as an exotic food for many years. Although ecologically and economically important, very little is known about this mushroom, including its diversity and population structure. Methodology and Principal Findings In this study, we analyzed 122 samples from five local populations representing the known distribution ranges of this mushroom in southern China. We investigated the genetic diversity and geographic structure of this mushroom using sequences from four DNA fragments. Our analyses identified that this mushroom contained at least three divergent lineages: one corresponds to a recently described species Russula griseocarnosa from southern China and the remaining two likely represent two novel species. While these lineages were prominently structured geographically based on ITS sequences, evidence for ancient and/or recent gene flow was also identified within individual lineages. In addition, a local population from Ailaoshan in central Yunnan Province where 85 of our 122 specimens came from showed clear evidence of recombination. Conclusion and Significance The ectomycorrhizal mushroom “Dahongjun” from southern China is a species complex with at least three divergent lineages. These lineages are largely geographically structured and there is evidence for recombination in nature. Our results indicate mature Dahongjun mushrooms with abundant basidiospores are important for the reproduction of this mushroom in nature and that individual populations of this species should be managed separately.

New species and distinctive geographical divergences of the genus Sparassis (Basidiomycota): evidence from morphological and molecular data

Species of the genus Sparassis in East Asia were investigated using morphology and DNA sequences data. Phylogenetic analyses inferred from sequences of the internal transcribed spacer (ITS), the nuclear gene coding for the ribosomal large subunit (nLSU) and partial gene coding RNA polymerase subunit II (rpb2) strongly supported lineages corresponding to morphological features. Three taxa, S. subalpina, S. cystidiosa f. flabelliformis and S. latifolia were recognized from East Asia, and the former two taxa are new to science. The occurrence of S. latifolia in Japan and in the Russian Far East was confirmed. Geographical divergences of Sparassis in the Holarctic were observed. Most species have relatively narrow distribution ranges, and taxa with intercontinental distributions were not detected. Divergence of species in the Northern Hemisphere in different clades appears to have taken place at different times: the S. latifolia-crispa-radicata species complex appears to have undergone a recent radiation, while the S. subalpina-brevipes-spathularia species complex represents a relatively ancient speciation.

Four new genera of the fungal family Boletaceae

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.

Drainage isolation and climate change-driven population expansion shape the genetic structures of Tuber indicum complex in the Hengduan Mountains region.

The orogenesis of the Qinghai-Tibetan Plateau and the Quaternary climate changes have played key roles in driving the evolution of flora and fauna in Southwest China, but their effects on higher fungi are poorly addressed. In this study, we investigated the phylogeographic pattern of the Tuber indicum species complex, an economically important fungal group distributed in the Hengduan Mountains region. Our data confirmed the existence of two distinct lineages, T. indicum and T. himalayense, within this species complex. Three geographic groups (Groups W, N and C) were revealed within T. indicum, with Group W found in the paleo-Lancang River region, while Groups N and C corresponded to the two banks along the contemporary Jinsha River, suggesting that rivers have acted as barriers for gene flow among populations from different drainages. Historical range expansion resulted from climate changes was inferred in Group C, contributing to the observed gene flow among geographic populations within this group. Although no significant geographic structure was identified in T. himalayense, evidence of drainage isolation for this species was also detected. Our findings demonstrate that both topographic changes and Quaternary climate oscillations have played important roles in driving the genetic structures of the T. indicum species complex.