Table_2_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.

在多个陆地生态系统中，例如草原，植物与各种根际定植的暗分隔内共生菌（DSEs）共存，这些真菌相对频繁地侵染了这些环境中植物健康地下组织的真菌。它们是植物微生物群中的重要成员，并可能在不同的胁迫条件下对植物的存活产生各种影响；然而，它们与植物及更大生态系统相关的普遍功能仍然难以捉摸。尽管越来越多的研究聚焦于亚洲草原的DSEs，但我们的知识仍然有限。尤其是在蒙古，该国的草原地区占据着广阔的面积，关于这些根际侵染菌的信息尚不充足。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——克律洛夫针茅（Stipa krylovii）的DSEs进行表征。在自然草原中采集了根样本，并对其进行了真菌内共生菌的分离处理。为了对分离株进行分子鉴定，从所有研究的分离株中获取了核糖体DNA（nrDNA）的内转录间隔区（ITS）；此外，对于代表性分离株，还扩增并测序了部分翻译延长因子1-α（TEF）基因以及核糖体DNA的大亚基（LSU）和小亚基（SSU）。通过体外试验来检验真菌的粗糙共生性质，并可视化根际定植。在详细检查的135个分离株中，大多数（110个）属于子囊菌亚门（Ascomycota）的几个目，少数（25个）属于担子菌亚门（Basidiomycota）。大量分离株代表可能是新的分类群，其谱系与相对常见且已知的其他地理区域半干旱地区草类根内共生菌的相似性显著。这些内共生菌包括大刺座孢菌（Periconia macrospinosa）、波利微生物（Microdochium bolley）和暗边菌（Darksidea），其中暗边菌属占据了分离株的四分之一。我们发现了许多谱系，这些谱系不仅来自亚洲草原生态系统，还来自北美大草原和欧洲沙质草原。因此，我们的结果强化了全球干旱和半干旱草原中存在一个共同且优势的DSE群落核心组的假设。