Multilocus phylogenetic analyses of the polyporales (Homobasidiomycetes, Basidiomycota) and the helotiales (Leotiomycetes, Ascomycota)

The Polyporales includes many wood rot fungi, which play an important ecological role in the carbon cycle. The monophyly of the Polyporales was not supported and the phylogenetic structures within the Polyporales were not well resolved. The evolutionary relationships between polypores producing a white rot and those producing a brown rot were not clear. In this study, the nuclear protein coding gene rpb2 and mitochondrial protein coding gene atp6 were amplified from representatives of polypores and other major groups of Homobasidiomycetes, with an emphasis on Sparassis. Analyses including protein coding genes greatly improved resolution of the Polyporales phylogeny at different levels. The Polyporales was shown to be monophyletic, and polypores producing a brown rot were supported as closely related. Lineages within Sparassis were recognized based on molecular, morphological and geographic data, among which two new species of Sparassis were reported. Members of the Helotiales colonize various substrates and build up diverse relationships with the environment. Classification and systematics of the Helotiales have been mainly based on morphological studies, and are artificial and problematic. Molecular data from different ribosomal RNA region were generated from taxa representing all major helotialean groups and related fungi for the first time, and phylogenetic analyses under parsimony and likelihood criteria were applied to these data. The stipitate genera Cudonia and Mitrula were studied intensively. The results supported a transfer of Cudonia and Spathularia to the Rhytismatales based on molecular and morphological evidence. A new species of Cudonia was reported, and Spathulariopsis was proved to be a synonym of Spathularia . A new species of Mitrula was reported, and the life history of M. elegans was investigated. Ecological factors play important roles in shaping the evolution of helotialean fungi, and aquatic helotialean fungi were shown to be closely related. A new class Geoglossomycetes was suggested as a basal lineage in the Leotiomyceta, and eight helotialean lineages were recognized.