[Endophytic fungal communities of Stipa sp. roots in different types of steppes in northern China].

In order to explore the endophytic fungal communities of Stipa sp. roots in different types of steppes in the north of China, root tissues of Stipa sp. were collected from six different types of steppes, i.e., subalpine meadow, alpine meadow, Gobi desert, desert steppe, typical steppe, and meadow steppe across Xinjiang, Gansu and Inner Mongolia. A total of 213 isolates were obtained and sequenced, which were divided into 51 operational taxonomic units (OTUs) at the 97% similarity threshold and classified to 4 phyla, 7 classes, 23 families and 27 genera. Ascomycota was found to be the predominant flora (93.4% of the total isolates) at the level of phylum and distributed in all the six steppe types. The dominant genera other than Fusarium. (41.3 of the total isolates) in the six steppe types were different, such as Microdochium in subalpine meadow, Saccharicola and Aureobasidium in alpine meadow, Curvularia and Rhizopus in Gobi desert and Trichoderma in typical steppe. The endophytic fungal community from the alpine meadow contained the most abundant groups at the level of genus and phylum, and had the highest Margalef index, Shannon index and second highest evenness index after the desert steppe. By contrast, the lowest Margalef index was observed in the desert steppe and the lowest Shannon index and evenness index were found in the typical steppe. Furthermore, endophytic fungal communities from alpine meadow and desert steppe showed low similarity coefficients (0.12-0.25 and 0.13-0.22, respectively) with other steppe types. However, the similarity coefficients among the other four steppe types were relatively high, especially between the typical steppe and the meadow steppe (0.60). Redundancy analysis (RDA) showed that the altitude and latitude were the main environmental factors affecting endophytic fungal community distribution in the roots of Stipa sp. in the six steppe types.