Phylogeny and biogeography of the remarkable genus Bondarzewia (Basidiomycota, Russulales).

Bondarzewia is a conspicuous and widely distributed mushroom genus, but little is known about its origin and biogeography. Here, we investigated the systematics and biogeography of Bondarzewia species using multi-locus phylogenetic analysis. Four genetic markers, including the internal transcribed spacer (ITS), large nuclear ribosomal RNA subunit (nLSU), elongation factor 1-α (tef1) and mitochondrial small subunit rDNA (mtSSU), were used to infer the phylogenetic relationships of Bondarzewia. We performed Bayesian evolutionary analysis on the gene datasets of the largest and second largest subunits of RNA polymerase II (RPB1 and RPB2). From the results, we inferred that the maximum crown age of Bondarzewia is approximately 25.5 million-years-ago (Mya) and that tropical East Asia is likely to be its ancestral area, with three possible expansions leading to its distribution in North America, Europe and Oceania.