The project has three objectives: (1) Describe the biodiversity patterns of Glomeromycota in plant roots in selected global biodiversity hotspots. Current information about the global biodiversity patterns indicates major gaps in several types of ecosystems and geographic regions. We will focus on two contrasting geographic ecosystems: tropical forests and deserts. Descriptive biodiversity surveys of Glomeromycota will be implemented using existing methodological approach of PCR, cloning and sequencing. (2) Develop global database of Glomeromycota identified in plant roots. The database will include all published environmental sequences and relevant related information. As a critical part, synonymy of researcher-created operational taxonomic units will be created in order to progeress comparability of independent data. This will enable to create distribution maps of molecular AM fungal taxa, which will be provided online. This publicly accessible and searchable database will further generate understanding of worldwide biodiversity of Glomeromycota. (3) Identify the functional diversity patterns of Glomeromycota in an ecosystem that is well described in terms of Glomeromycota biodiversity patterns – boreo-nemoral forest - and the ecosystems studied for biodiversity in Obj.1. The interpretation of biodiversity patterns in terms of their functional significance is pivotal in order to understand ecosystem functioning and to predict the impact of management/disturbance and climate change on soil microbial communities. The experimentation complementing biodiversity surveys will use both native fungal inoculum and pre-existing isolates, in order to specify the functional profiles of fungal assemblages at locations. We will focus on description of functional properties of individual fungi and their assemblages in single plant and plant community conditions. Fungal growth (biomass) will be assessed in these conditions, and under different nutrient and water availability.