[Species diversity of dark septate endophytes in tundra plants of Changbai Mountains, Northeast China].

We isolated the dark septate endophytic (DSE) fungi from roots of typical plant species in the tundra of Changbai Mountains Nature Reserve, including , , , and , and studied their colonization. We further investigated the DSE community composition and species diversity of the four tundra plant species by using morphological characteristics combined with rDNA ITS sequence analysis. The results showed that DSE formed a typical structure of "microsclerotia" in roots of the four plant species. A total of 69 strains of DSE fungi were isolated from the root samples, belonging to 10 genera, and 12 species. They were , , , , , , , sp., , sp., sp., and , respectively. The DSE fungal species diversity was rich, and all these fungal species were firstly reported as DSE fungi in the alpine tundra belt of China. Among them, was the common and dominant species of all tundra plants. The Simpson, Pielou, and Shannon diversity indices of DSE fungi of the four plant species of tundra differed significantly. Our results showed that tundra plants have rich diversity of DSE fungi, and they can form a good symbiotic relationship, which enhance the adaptability of tundra plants to the harsh environment.