Table_1_Root-Colonizing Endophytic Fungi of the Dominant Grass Stipa krylovii From a Mongolian Steppe Grassland.XLSX

In several terrestrial ecosystems such as grasslands, plants live together with various root-colonizing dark septate endophytes (DSEs), fungi that are relatively frequent colonizers of healthy belowground tissues of plants in these environments. They are important members of the plant microbiota and may have various effects on plant survival under different stress conditions; however, their general functions in relation to plants and the greater ecosystem remain elusive. Although an increasing number of studies has been published focusing on DSEs in Asian grasslands, our knowledge is limited. Especially in Mongolia, where the steppe region represents a significant area, information is not available on these root colonizers. In this study, we aimed to characterize DSEs of a common dominant gramineous plant species, Stipa krylovii in a semiarid grassland of Mongolia. Root samples were collected in a natural steppe and were processed for isolation of fungal endophytes. For molecular identification of the isolates, the internal transcribed spacer (ITS) region of the nrDNA was obtained for all the isolates investigated; furthermore, the partial translation elongation factor 1-α (TEF) gene and large subunit (LSU) and small subunit (SSU) of rDNA were also amplified and sequenced in case of representative isolates. In vitro tests were used to examine the rough symbiotic nature of the fungi, and root colonization was visualized. A majority of the 135 isolates examined in detail was found to belong to several orders of Ascomycota (110 isolates) and some to Basidiomycota (25 isolates). A significant number of the isolates represented presumably novel taxa, and dominant similarities of the lineages have been found with relatively frequent and known grass root endophytes of semiarid areas in other geographic regions. These endophytes included Periconia macrospinosa, Microdochium bolley, and Darksidea, the genus of which comprised one fourth of the isolates. We found numerous lineages, which have been detected not only from Asian steppe ecosystems, but also from prairies in North America and sandy grasslands in Europe. Therefore, our results strengthen the hypothesized worldwide presence of a common and dominant core group of a DSE community in arid and semiarid grasslands.

在众多陆地生态系统中，如草原等，植物与多种根际定殖暗隔内生菌（DSEs）共生，这些真菌在环境中的健康地下组织中相对频繁地定殖，是植物微生物群落中的重要成员。它们可能在不同的胁迫条件下对植物的生存产生各种影响；然而，它们与植物及更大生态系统的总体功能仍显得扑朔迷离。尽管关于亚洲草原中DSEs的研究日益增多，但我们的知识仍显局限。特别是在蒙古，其草原区域占据着显著的地域，关于这些根际定殖真菌的信息尚不充足。在本研究中，我们旨在对蒙古半干旱草原中一种常见优势禾本科植物物种——克氏针茅（Stipa krylovii）的DSEs进行特征描述。在自然草原中采集了根样本，并对其进行处理以分离真菌内生菌。为了对分离株进行分子鉴定，对所有调查的分离株获得了核糖体DNA（nrDNA）的内转录间隔区（ITS）区域；此外，对于代表性分离株，还扩增并测序了部分翻译延伸因子1-α（TEF）基因以及核糖体DNA的大亚基（LSU）和小亚基（SSU）。通过体外实验检验了真菌的粗糙共生性质，并可视化了根际定殖。在详细检查的135个分离株中，大多数属于子囊菌门（110个分离株），少数属于担子菌门（25个分离株）。相当数量的分离株代表了可能的新分类群，且这些谱系的显著相似性与其他地理区域半干旱地区相对常见和已知的草类根内生菌具有相关性。这些内生菌包括大刺盘菌（Periconia macrospinosa）、博利氏微核菌（Microdochium bolley）和暗面菌属（Darksidea），其中暗面菌属占分离株的四分之一。我们发现了众多谱系，不仅来自亚洲草原生态系统，还来自北美的草原和欧洲的沙质草地。因此，我们的研究结果加强了关于全球干旱和半干旱草原中DSE群落存在一个共同且优势的核心群体的假设。