The role of arbuscular mycorrhizal fungi in agro- and natural ecosystems

Symbionts called 'mycorrhizal fungi' occur in most biomes on earth, and are a fundamental reason for plant growth and development on the planet. The most common group of mycorrhizal fungi is that of the arbuscular mycorrhizal fungi (AMF), which colonize the roots of over 80% of land plant families, but they cannot as yet be cultured away from the host plant. AMF are primarily responsible for nutrient transfer from soil to plant, but have other roles such as soil aggregation, protection of plants against drought stress and soil pathogens, and increasing plant diversity. This is achieved by the growth of their fungal mycelium within a host root and out into the soil beyond. There is an urgent need to study the below-ground microbiology of soils in agro- and natural ecosystems, as AMF are pivotal in closing nutrient cycles and have a proven multifunctional role in soil-plant interactions. More information is also needed on the biodiversity and functional diversity of these microbes and their interactions with crops and plants.