Changes of root AMF community structure and colonization levels under distribution pattern of geographical substitute...

The establishment of symbiotic relationship between arbuscular mycorrhizal fungi (AMF) and roots is a mutually beneficial process and plays an important role in plant succession in ecosystems. However, there is less understanding of information about the AMF community in roots under vegetation succession on a large regional scale, especially the spatial variation in the AMF community and its potential ecological functions. Here, we elucidated the spatial variations in root AMF community structure and root colonization along a distribution pattern of four zonal Stipa species in arid and semiarid grassland systems and explored key factors regulating AMF structure and mycorrhizal symbiotic interactions. Four Stipa species established a symbiosis with AMF, and annual mean temperature (MAT) and soil fertility were the main positive and negative driving factors of AM colonization, respectively. The Chao richness and Shannon diversity of AMF community in the root system of Stipa species tended to increase firstly from S. baicalensis to S. grandis and then decreased from S. grandis to S. breviflora. While evenness of root AMF and root colonization showed a trend of increasing from S. baicalensis to S. breviflora, and biodiversity was principally affected by soil total phosphorus (TP), organic phosphorus (Po) and MAT. It is emphasized that Stipa species have certain dependence on AMF, especially in a warming environment, and the root AMF community structure among the four Stipa taxa was different. Additionally, the composition and spatial distribution of root AMF in host plants varied with MAT, annual mean precipitation (MAP), TP and host plant species. These results will broaden our understanding of the relationship between plant and AMF communities and their ecological role, and provide basic information for the application of AMF in the conservation and rehabilitation of forage plants in degraded semiarid grasslands.