Arbuscular mycorrhizal fungal diversity is affected by soil salinity and soil nutrients in typical saline-sodic grasslands dominated by Leymus chinensis

Restoring and reconstructing the salt-affected degraded ecosystem is receiving more and more attention in many parts of the world, especially semi-arid areas. Unfortunately, knowledge about the potential role of natural arbuscular mycorrhizal (AM) fungi was limited. This work examined the regional factors that drove the variations in AM fungal diversity in Songnen Plain, a typical saline-sodic degraded grassland. Soils were sampled in 45 random sites, 150 operational taxonomic units (OTUs) belonging to Glomeromycota were identified. Among these OTUs, 129 and 103 OTUs were classified to Glomerales and Glomus, respectively. The coefficients of variation of total diversity index were 35.61% and the total effects of soil salinity and nutrients collectively accounted for 31.2, 11.8, 47.3, and 64.2% of the variations in Sobs, Chao, Shannon, and Simpson indices, respectively. The climatic variables and geographical location had no significant effects on the variations of AM fungal diversity. Multiple linear regression models showed that soil pH, electrical conductivity (EC), available N and organic C were the most main influencing factors. This research highlighted the wide distribution of AM fungi and thus might promote the development of new techniques that apply natural AM fungi to restore saline-sodic degraded grasslands.