Biodiversity of arbuscular mycorrhizal fungi in the hot-dry valley of the Jinsha River, southwest China

The diversity and community structure of arbuscular mycorrhizal fungi (AMF) in two sites (Pudu and Xiao Rivers) with different vegetation in the hot-dry valley of Jinsha River, southwest China, were investigated. Forty-three morphospecies of AMF were identified. Among them, 28 were in the genus Glomus, 7 in Acaulospora, 4 in Scutellospora, 2 in Entrophospora and 2 in Gigaspora. The most common and frequent genus was Glomus, and several species of Glomus and Gigaspora were the most common and frequent among the 43 species present in this hot-dry ecosystem. Although Sorenson's coefficient (Cs = 0.83) revealed considerable overlap in AM fungal species composition, AMF community structure varied considerably between the two sites. Non-random associations between AMF and host plants were commonly observed in this study and suggest some degree of host preference at the species level. AMF spore density (SD) was positively correlated with species richness (SR), and both were differed significantly between the undisturbed Pudu River site and the disturbed Xiao River site. We suggest that the hot-dry valley of Jinsha River appeared to harbor a high diversity of AMF with an uneven distribution, and that natural disturbance (mud-rock flow and landslides) is important in determining the diversity, density, and distribution of AMF.