0 907, RI = 0.943, RC = 0.855. The alignments of Trebouxia ITS and Asterochloris ITS contained several closely related accessions from Genbank including all taxonomically identified and several taxonomically unidentified species (43 for Trebouxia, 35 for Asterochloris), plus accessions from other high Alpine and Antarctic areas JPH203 included in order to get information about intra-specific sequence variation and to see whether the species and haplotypes could be assigned to known BIRB 796 mouse clades.

Information about the samples is summarized in Online Resource 1. Fig. 2 Phylogeny of concatenated ITS and psbL-J sequences of Trebouxia specimens from the four SCIN-sites, combined with own samples from Antarctica and Austria. The bars beside the phylogeny show the provenance of the specimens in the respective habitats. The bootstrap values with >70 support of MP and ML analyses were directly mapped on this Bayesian tree with >0.92 support (branches in bold) Fig. 3 Phylogeny of ITS sequences of Asterochloris specimens from the four SCIN-sites, combined with downloaded accessions from Genbank. The bars beside the phylogeny show the provenance of the specimens in the respective habitats. The bootstrap values with >70 support of MP and ML analyses were directly mapped on this Bayesian tree with >0.92 support (branches

in bold) The ML and Bayesian analyses Cell Cycle inhibitor recovered the same well-supported clades as the MP analysis. The Bayesian consensus trees, with the support values of all three analyses are shown in Online Resource 2 and Figs. 2 and 3. The plotted bars beside the trees show the sample provenance (see also Table 4). Phylogenetic analysis Trebouxia ITS (Online Resource 2) This phylogenetic reconstruction was performed to get an overview of the relationship between the photobionts from soil crust lichens and other, already published, sequences of Trebouxia species. It revealed 16 well supported, monophyletic groups of which 12 are part of this study and several weakly supported clades of Trebouxia

photobionts. The tree was rooted with Chloroidium saccharophilum the closest related algal group. In addition to the already well known tuclazepam Trebouxia species (T. showmanii, T. gigantea, T. asymmetrica, T. arboricola, T. decolorans, T. jamesii, T. impressa) and other published but taxonomically unidentified clades (T. sp. URa1-4, T. sp. URa6 resp. T. sp. Guzow, etc.), several other clades appeared. The backbone was not well supported and therefore the topology of the different clades to each other will not be discussed. A new and well-supported group with four accessions occurred only in Tabernas and was closely related to T. gigantea.T. asymmetrica, which contained two accessions from Ruine Homburg, was a sister to clade T. sp. URa4 found in several accessions from Hochtor as well as from Ruine Homburg. Another new group (T. sp.