Phylogenetic relationships in Cortinarius with focus on North European species

Authors: Stensrud, Øyvind & Reier-Røberg, Kjetil & Schumacher, Trond & Orr, Russell & Høiland, Klaus
Journal: Karstenia, Volume 54 (2014), Issue 2, pages 57-71.
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Key words: Cortinarius, phylogeny, morphology, secondary compounds, ecology

Cortinarius is an ectomycorrhizal Agaricales genus with high diversity of which rDNA sequences of 86 species together with four outgroup taxa were investigated phylogenetically by aid of Maximum Likelihood and Bayesian analyses. The Cortinarius data set represents 81 taxa from the Northern Hemisphere showing the main variation spectrum among the species. In addition, five species from the Southern Hemisphere are included. The phylogenetic tree of Cortinarius gives statistical support to twelve monophyletic groups in the upper level. They are discussed in context of morphology, chemistry (secondary compounds), and ecology. The phylogenetic tree lacks, however, satisfactory support for its backbone. Several species could not be included in any group, especially those forming the basal framework of the tree. Of special interest is a “superclade” comprising eight of our monophyletic clades and two singletons. Here we find the majority of species with soluble pigments of octaketide origin, all species with compounds of nonaketide origin, the majority of species with hygrophaneous pileus, few species with viscid pileus, and no species with bulbous stipe base. Moreover, all species except one have duplex pileus cuticle. The morphological traits are not indicative for any clade, although some are more frequent in some clades than others. During the evolution they have been gained and lost several times. The chemical characteristics are – to a certain degree – more indicative for the clades. The evolution and ecological role of these compounds are discussed. Concerning the North European species, there are ecological differences between the clades, especially between clades specializing to rich or calcareous forests and clades specializing to poor forests or arctic-alpine environments.