Lichens have high tolerance to harsh environmental conditions, where lichen symbiont interactions (e.g. myco- and photobionts) may play a crucial role. The characterization of fungal-algal association patterns is essential to understand their symbiotic interactions. This study investigated fungal-algal association patterns in Icelandic cetrarioid lichens using a multi-locus phylogenetic framework, including fungal nrITS, MCM7, mtSSU, RPB1 and RPB2 and algal nrITS, nrLSU, rbcL and mtCOXII data. Most Icelandic cetrarioid lichenized fungi were found to be specifically associated to the known Trebouxia clade “S” (Trebouxia simplex/suecica group), whereas the lichen-forming fungus Cetrariella delisei forms a symbiosis with a previously unrecognized lineage of Trebouxia, provisionally named as the “D” clade. This new Trebouxia lineage is supported by maximum likelihood and Bayesian phylogenetic analyses using all four included algal loci.

中文翻译：

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地衣藻类藻类Trebouxia（Trebouxiophyceae，Chlorophyta）的系统发生多样性：冰岛线粒体地衣真菌（Parmeliaceae，Ascomycota）的真菌-藻类结合模式的新谱系和新见解

地衣对恶劣的环境条件具有高度的耐受性，在这种环境中，地衣共生体相互作用（例如霉菌和光生生物）可能起着至关重要的作用。真菌-藻类缔合模式的表征对于理解它们的共生相互作用至关重要。这项研究使用多位点系统发育框架，包括真菌nrITS，MCM7，mtSSU，RPB1和RPB2以及藻类nrITS，nrLSU，rbcL和mtCOXII数据，对冰岛ceriorioid地衣中的真菌-藻类缔合模式进行了研究。发现最冰岛cetrarioid地衣真菌具体关联于已知Trebouxia进化枝“S”（Trebouxia单面/ suecica组），而形成地衣的真菌Cetrariella delisei与之前无法识别的Trebouxia谱系（共称为“ D”进化枝）形成共生关系。这种新的Trebouxia谱系得到最大可能性和使用所有包含的四个藻类基因座的贝叶斯系统发育分析的支持。