Arbuscular mycorrhizal fungi (AMF) play central roles in terrestrial ecosystems by interacting with both above and belowground communities as well as by influencing edaphic properties. The AMF communities associated with the roots of the fern Botrychium lunaria (Ophioglossaceae) were sampled in four transects at 2400 m a.s.l. in the Swiss Alps and analyzed using metabarcoding. Members of five Glomeromycota genera were identified across the 71 samples. Our analyses revealed the existence of a core microbiome composed of four abundant Glomus operational taxonomic units (OTUs), as well as a low OTU turnover between samples. The AMF communities were not spatially structured, which contrasts with most studies on AMF associated with angiosperms. pH, microbial connectivity and humus cover significantly shaped AMF beta diversity but only explained a minor fraction of variation in beta diversity. AMF OTUs associations were found to be significant by both cohesion and co‐occurrence analyses, suggesting a role for fungus–fungus interactions in AMF community assembly. In particular, OTU co‐occurrences were more frequent between different genera than among the same genus, rising the hypothesis of functional complementarity among the AMF associated to B. lunaria. Altogether, our results provide new insights into the ecology of fern symbionts in alpine grasslands.

中文翻译：

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生物因素和非生物因素影响与蕨类植物Botrychium lunaria（Ophioglossaceae）根系相关的丛枝菌根真菌群落。

丛枝菌根真菌（AMF）通过与地上和地下社区互动以及影响水生特性而在陆地生态系统中发挥核心作用。在瑞士阿尔卑斯山，以2400 m asl的四个横断面采样了与蕨菜蓝藻（Ophioglossaceae）的根相关的AMF群落，并使用元条形码进行了分析。在71个样本中鉴定了五个Glomeromycota属的成员。我们的分析表明存在由四个丰富的Glomus组成的核心微生物组操作分类单位（OTU），以及样品之间OTU转换率低。AMF群落不是空间结构的，这与大多数与被子植物有关的AMF研究相反。pH值，微生物连接和腐殖质盖显著形AMF测试多样性，但只有在解释变差的一小部分的β多样性。通过内聚和共现分析，发现AMF OTU关联非常重要，表明真菌-真菌相互作用在AMF社区大会中发挥了作用。特别是，不同属之间的OTU共存比同属属更频繁，这增加了与月球芽孢杆菌相关的AMF之间功能互补的假设。 总而言之，我们的结果为高山草原蕨类共生体的生态学提供了新的见解。