Abstract
Arbuscular mycorrhizal (AM) fungi are ubiquitous microbes in terrestrial habitats with important roles in ecosystem functioning, but knowledge of their large scale biogeography remains particularly limited in some regions and in association with woody host species. The objective of this study was to characterize diversity and community structure of AM fungi associated with the woody plants Alnus and Rubus in Eastern Europe and Iran-Turkey. AM fungi were identified on the basis of SSU rRNA gene sequences: 39 virtual taxa (VT) were detected across 24 study sites, with high dominance by two Glomeraceae VT (VT113 and VT115 related to Rhizoglomus intraradices-irregulare group). Community structure of AM fungi was driven by climatic and spatial variables, while host identity influenced the frequency of AM fungal occurrence. AM fungal communities from species-poor sites were subsets of those in richer sites, indicating nestedness and a progressive loss from the AM fungal species pool.