Data from: Genotypic diversity in root-endophytic fungi reflects efficient dispersal and environmental adaptation

Studying community structure and dynamics of plant-associated fungi is the basis for unravelling their interactions with hosts and ecosystem functions. A recent sampling revealed that only a few fungal groups, as defined by internal transcribed spacer region (ITS) sequence similarity, dominate culturable root endophytic communities of nonmycorrhizal Microthlaspi spp. plants across Europe. Strains of these fungi display a broad phenotypic and functional diversity, which suggests a genetic variability masked by ITS clustering into operational taxonomic units (OTUs). The aims of this study were to identify how genetic similarity patterns of these fungi change across environments and to evaluate their ability to disperse and adapt to ecological conditions. A first ITS-based haplotype analysis of ten widespread OTUs mostly showed a low to moderate genotypic differentiation, with the exception of a group identified as Cadophora sp. that was highly diverse. A multilocus phylogeny based on additional genetic loci (partial translation elongation factor 1α, beta-tubulin and actin) and amplified fragment length polymorphism profiling of 185 strains representative of the five dominant OTUs revealed a weak association of genetic differences with geography and environmental conditions, including bioclimatic and soil factors. Our findings suggest that dominant culturable root endophytic fungi have efficient dispersal capabilities, and that their distribution is little affected by environmental filtering. Other processes, such as inter- and intraspecific biotic interactions, may be more important for the local assembly of their communities.

探究植物关联真菌的群落结构与动态，是解析其与宿主的互作关系及生态系统功能的基础。近期一项采样研究显示，在欧洲范围内的非菌根薪草属（Microthlaspi spp.）植物中，仅少数基于内部转录间隔区（internal transcribed spacer region，ITS）序列相似性定义的真菌类群主导了其可培养根系内生真菌群落。这些真菌的菌株展现出广泛的表型与功能多样性，这表明ITS聚类为操作分类单元（operational taxonomic units，OTUs）的过程掩盖了其遗传变异。本研究的目的在于明确这些真菌的遗传相似性模式如何随环境变化，并评估其扩散能力以及对生态条件的适应能力。针对10个广布OTUs的首次基于ITS的单倍型分析结果显示，除1个鉴定为垫盘孢属（Cadophora sp.）的类群具有高度多样性外，其余类群的基因型分化程度多为低等到中等水平。基于额外遗传位点（部分翻译延伸因子1α（translation elongation factor 1α）、β微管蛋白（beta-tubulin）及肌动蛋白（actin））以及对代表5个优势OTUs的185株菌株进行的扩增片段长度多态性（amplified fragment length polymorphism）分型分析构建的多位点系统发育结果显示，遗传差异与地理及环境条件（包括生物气候与土壤因子）之间仅存在微弱关联。本研究结果表明，优势可培养根系内生真菌具备高效的扩散能力，其分布几乎不受环境过滤作用的影响。其他过程，如种间与种内生物互作，可能对其群落的本地组装更为关键。