TAXONOMIC DIVERSITY AND COMMUNITY COMPOSITION OF THE ARBUSCULAR MYCORRHIZAL FUNGI IN THE INNER MONGOLIA STEPPE, CHINA

Steppe ecosystem is one of the most important elements of the terrestrial lands on Earth. As one of the most widespread types of soil microbes, arbuscular mycorrhizal (AM) fungi play important roles in maintaining the diversity and structure of plant communities. This study examined the species diversity and community composition of AM fungi living with dominant plants in Xilingol steppe, Inner Mongolia. Three native plant species, Leymus chinensis, Stipa grandis and Cleistogenes squarrosa were chosen. It was found that all three plants were well colonized with AMF but the AM infection rate of the Cleistogenes squarrosa was significantly lower than those of the other two species. By cloning and sequencing, we identified the AM fungi within the roots of three plant species using PCR amplified 18S-rDNA fragments with AMF-specific primers. We observed 51 operational taxonomic units (OTUs) belonging to six genera in five families with members of Glomus dominating in the roots of all the three plants species. The diversity of AMF in the roots of Leymus chinensis was the highest. Species (OTU) richness of AMF was the highest in the roots of Stipa grandis and lowest in the roots of Cleistogenes squarrosa. Furthermore, Nonmetric multidimensional scaling (NMDS) analysis indicated the host plant species were not significantly related to the AM fungi community composition within their roots. Our results indicated that in Xilingol typical steppe, in terms of dominant plant species, host preference may not significantly drive the differences of AM fungal community composition within their roots, though a few OTUs and genera appeared to be specific to the different host.