Mycothalli, symbioses between liverworts and soil fungi, have not previously been recorded in the Arctic. Here, 13 species of leafy liverwort from west Spitsbergen in the High Arctic are examined for the symbiosis using epifluorescence microscopy and sequencing of fungal ribosomal (r)RNA genes amplified from plant tissues. Microscopy showed that intracellular hyphal coils, key indicators of the symbiosis, were frequent (>40% stem length colonized) in nine species of liverwort in the families Anastrophyllaceae, Lophoziaceae, Cephaloziellaceae, Cephaloziaceae and Scapaniaceae, with hyphae occurring frequently (>40% cells occupied) in the rhizoids of 10 species in the same families. Dark septate hyphae, apparently formed by ascomycetes, were frequent on the stems of members of the Anastrophyllaceae, Cephaloziellaceae and Cephaloziaceae, and typically those growing on acidic mine tailings. Sequencing of fungal rRNA genes showed the presence of nine distinct groups (based on a 3% cut-off for ITS sequence divergence) of the basidiomycete Serendipita in the Anastrophyllaceae and Lophoziaceae, with ordinations and correlative analyses showing the presence of the genus to be positively associated with the frequency of hyphal coils, the occurrence of which was positively associated with edaphic factors (soil δ¹⁵N value and concentrations of moisture, nitrogen, carbon and organic matter). We propose that the frequency of mycothalli in leafy liverworts on west Spitsbergen, which is an order of magnitude higher than at lower latitudes, may arise from benefits conferred by mycobionts on their hosts in the harsh environment of the High Arctic.

Mycothalli，苔类植物和土壤真菌之间的共生体，以前在北极没有记录。在这里，使用落射荧光显微镜和真菌核糖体（r)从植物组织中扩增的RNA基因。显微镜检查显示，在 Anastrophyllaceae、Lophoziaceae、Cephaloziellaceae、Cephaloziaceae 和 Scapaniaceae 科的 9 种苔类植物中，细胞内菌丝卷是共生的关键指标频繁出现（>40% 的茎长定植），菌丝经常出现（>40% 细胞占据）在同科10种的根状茎中。暗色有隔菌丝，显然是由子囊菌形成的，常见于 Anastrophyllaceae、Cephaloziellaceae 和 Cephaloziaceae 成员的茎上，通常生长在酸性尾矿上。真菌r RNA 基因的测序 显示担子菌Serendipita存在九个不同的组（基于 ITS 序列差异的 3% 截止值）  在 Anastrophyllaceae 和 Lophoziaceae 中，排序和相关分析表明该属的存在与菌丝盘绕的频率呈正相关，菌丝盘旋的发生与土壤因子（土壤δ ¹⁵ N 值和水分、氮的浓度）呈正相关 、碳和有机物）。我们提出，在西斯匹次卑尔根岛的多叶苔类植物中，真菌菌体的频率比低纬度地区高一个数量级，这可能是由于真菌在高北极恶劣环境中赋予宿主的好处。