Colonization of dark septate endophytes in roots of Ammopiptanthus mongolicus and its associated plants as influenced by soil properties

Aims Dark septate endophytes (DSE) are commonly detected in plant roots in different ecosystems. However, so far our knowledge about the ecological significance of DSE in semiarid and arid lands is limited. The main objec- tive of this study was to compare the colonization status and ecological distribution of DSE in Ammopiptanthus mongolicus and its associated plants in desert habitats. Methods In July 2013, soil and root samples of A. mongolicus and its associated plants were collected from three sites, including Yinchuan, Shapotou and Minqin located in northwest China. At each sampling site, samples were collected at five depth intervals, 0-10, 10-20, 20-30, 30-40 and 40-50 cm, respectively. Important findings The roots of A. mongolicus and its associated plants were infected by DSE which could be characterized by typical septate hyphae and microsclerotia. Microsclerotia of A. mongolicus were compact lumps, while the associated plants had scattered microsclerotia. In the same site, microsclerotia colonization in A. mongo- licus and its associated plants showed no significant difference, but hyphal colonization, colonization intensity and total colonization of A. mongolicus were much higher than that of its associated plants. In different sites, the colo- nization intensity and total colonization of DSE in A. mongolicus exhibited a pattern as Shapotou > Yinchuan > Minqin, and these indexes in associated plants were Yinchuan > Minqin > Shapotou. Plant species and soil layer had significant effects on the colonization and distribution of DSE as well as soil properties. The path coefficient and principal component analysis indicated that soil organic matter, total extractable glomalin, phosphatase and available K are the main influencing factors, which directly affected the colonization of DSE in desert environ- ment, Northwest China.