Phylogenetic analyses of the Lyophylleae (Agaricales, Basidiomycota) based on nuclear and mitochondrial rDNA sequences

Current classifications of the Lyophylleae and the importance of siderophilous granulation in the basidia for the classification of agaricoid fungi were evaluated using parsimony analyses of sequence data from the nuclear ribosomal large subunit gene (nLSU), the internal transcribed spacer region of the nuclear ribosomal array (ITS), and the mitochondrial ribosomal small subunit gene (mtSSU). These three different data partitions were phylogenetically congruent on the basis of the Mickevich–Farris statistical test, but not from the ILD and the Templeton tests. Bootstrap supports for nodes in phylogenetic trees generated from combined nLSU, ITS, and mtSSU sequence data were generally higher than those in trees generated from individual data sets. This suggests a lack of major conflict in the phylogenetic signal among the different data sets. We conclude that the Mickevich–Farris test is more appropriate for estimating congruence and combinability between different sources of molecular data than the more widely used ILD and Templeton tests, at least when the different data sets have their respective resolution power at different depths in the phylogeny. Results of the combined analyses show that the Entolomataceae are a sister group to a clade composed of the Lyophylleae, Termitomyceteae, and Tricholomateae p.p. This implies that presence of siderophilous granulation in the basidia of agaric fungi has probably a single origin, and would have been lost in the Tricholomateae. Inclusion of the Termitomyceteae within the Lyophylleae suggests homology of the macro type granulation. Because the exact placement of Tricholomateae pro parte remains uncertain, it remains unclear whether the Lyophylleae (including Termitomyceteae) are monophyletic or paraphyletic. Within the Lyophylleae, genera Lyophyllum and Calocybe are shown to be artificial, as are Lyophyllum sections Lyophyllum, Difformia, and Tephrophana. Four main natural groups of Lyophylleae have been identified that should serve as a basis for developing a more natural classification system for these fungi.