Phylogenetic relationships in Auriculariales and related groups - hypotheses derived from nuclear ribosomal DNA sequences

In order to estimate phylogenetic relationships in the Auriculariales sensu Bandoni (1984) and allied groups we have analysed a representative sample of species by comparison of nuclear coded ribosomal DNA sequences, applying models of neighbour joining, maximum parsimony, conditional clustering, an d maximum likelihood. Analyses of the 5' terminal domain of the gene coding for the 28 S ribosoma l large subunit supported the monophyly of the Dacrymycetales and Tremellal es, while the monophyly of the Auriculariales was not supported. The Sebaci naceae. including the genera Sebacina. Efibulobasidium, Tremelloscypha, and Craterocolla, was confirmed as a monophyletic group, which appeared distan t from other taxa ascribed to the Auriculariales. Within the latter the fol lowing subgroups were significantly supported: in a group of closely relate d species containing members of the genera Auricularia, Exidia, Exidiopsis, Heterochaete, and Eichleriella; (2) a group comprising species of Bourdoti a and Ductifera; (3) a group of globose-spored species of the genus Basidio dendron: (4) a group that includes the members of the genus Myxarium and Hy aloria pilacre; (5) a group consisting of species of the genera Protomeruli us, Tremellodendropsis, Heterochaetella. and Protodontia. Additional analys es of the internal transcribed spacer (ITS) region of the species contained in group (1) resulted in a separation of these fungi due to their basidial types.