Molecular phylogeny and global diversity of the remarkable genus Bondarzewia (Basidiomycota, Russulales)

Abstract

Bondarzewia is a remarkable polypore genus due to its relatively large poroid basidiocarps and belongs to order Russulales according to recent phylogenetic analyses. Two species, B. berkeleyi and B. mesenterica, are commonly reported in North America and Europe but the genus is poorly known elsewhere. We explored the phylogeny and species diversity of Bondarzewia based on a larger number of samples covering a wider geographic range, including eastern Asia, Europe, North America, Oceania and South America. Sequences were generated from the nuc rDNA region encompassing the internal transcribed spacers 1 and 2, along with the 5.8S rDNA (ITS) and nuc 28S rDNA D1-D2 domains (28S), and the final dataset included 28 samples of which 21 ITS and 28S sequences were newly generated. As a result of phylogenetic analyses and comparison of morphological features we propose a new classification of the genus recognizing 10 species. Most of the novel taxonomic concepts are geographically restricted in contrast to the past broad species concepts, especially of B. berkeleyi. In addition, a degree of host specificity is observed with B. mesenterica, B. occidentalis, B. podocarpi, B. propria and B. submesenterica apparently restricted to gymnosperms and all others on angiosperm hosts where known. Three new species, B. kirkii, B. occidentalis and B. submesenterica, are described and illustrated. Three new combinations (B. dickinsii, B. propria, B. retipora) are revived from synonymy under B. berkeleyi. A key to known species of Bondarzewia is provided.