Multigene phylogeny and taxonomic revision of Atheliales s.l.: Reinstatement of three families and one new family, Lobuliciaceae fam. nov

Atheliales (Agaricomycetes, Basidiomycota) is an order mostly composed of corticioid fungi, containing roughly 100 described species in 20 genera. Members exhibit remarkable ecological diversity, including saprotrophs, ectomycorrhizal symbionts, facultative parasites of plants or lichens, and symbionts of termites. Ectomycorrhizal members are well known because they often form a major part of boreal and temperate fungal communities. However, Atheliales is generally understudied, and molecular data are scarce. Furthermore, the order is riddled with many taxonomic problems; some genera are non-monophyletic and several species have been shown to be more closely related to other orders. We investigated the phylogenetic position of genera that are currently listed in Atheliales sensu lato by employing an Agaricomycetes-wide dataset with emphasis on Atheliales including the type species of genera therein. A phylogenetic analysis based on 5.8S, LSU, rpb2, and tef1 (excluding third codon) retrieved Atheliales in subclass Agaricomycetidae, as sister to Lepidostromatales. In addition, a number of Atheliales genera were retrieved in other orders with strong support: Byssoporia in Russulales, Digitatispora in Agaricales, Hypochnella in Polyporales, Lyoathelia in Hymenochaetales, and Pteridomyces in Trechisporales. Based on this result, we assembled another dataset focusing on the clade with Atheliales sensu stricto and representatives from Lepidostromatales and Boletales as outgroups, based on ITS (ITS1-5.8S-ITS2), LSU, rpb2, and tef1. The reconstructed phylogeny of Atheliales returned five distinct lineages, which we propose here as families. Lobulicium, a monotypic genus with a distinct morphology of seven-lobed basidiospores, was placed as sister to the rest of Atheliales. A new family is proposed to accommodate this genus, Lobuliciaceae fam. nov. The remaining four lineages can be named following the family-level classification by Jülich (1982), and thus we opted to use the names Atheliaceae, Byssocorticiaceae, Pilodermataceae, and Tylosporaceae, albeit with amended circumscriptions.

A revised family-level classification of the Polyporales (Basidiomycota)

Polyporales is strongly supported as a clade of Agaricomycetes, but the lack of a consensus higher-level classification within the group is a barrier to further taxonomic revision. We amplified nrLSU, nrITS, and rpb1 genes across the Polyporales, with a special focus on the latter. We combined the new sequences with molecular data generated during the PolyPEET project and performed Maximum Likelihood and Bayesian phylogenetic analyses. Analyses of our final 3-gene dataset (292 Polyporales taxa) provide a phylogenetic overview of the order that we translate here into a formal family-level classification. Eighteen clades are assigned a family name, including three families described as new (Cerrenaceae fam. nov., Gelatoporiaceae fam. nov., Panaceae fam. nov.) and fifteen others (Dacryobolaceae, Fomitopsidaceae, Grifolaceae, Hyphodermataceae, Incrustoporiaceae, Irpicaceae, Ischnodermataceae, Laetiporaceae, Meripilaceae, Meruliaceae, Phanerochaetaceae, Podoscyphaceae, Polyporaceae, Sparassidaceae, Steccherinaceae). Three clades are given informal names (/hypochnicium,/climacocystis and/fibroporia + amyloporia). Four taxa (Candelabrochete africana, Mycoleptodonoides vassiljevae, Auriporia aurea, and Tyromyces merulinus) cannot be assigned to a family within the Polyporales. The classification proposed here provides a framework for further taxonomic revision and will facilitate communication among applied and basic scientists. A survey of morphological, anatomical, physiological, and genetic traits confirms the plasticity of characters previously emphasized in taxonomy of Polyporales.