The arbuscular mycorrhizal symbiosis (AMS) is one of the most ancient and broadly occurring mutualistic associations between plants and arbuscular mycorrhizal fungi (AMF). This intimate relationship improves plant mineral nutrient acquisition, which potentially enhances crop yield. In addition, AMS can increase plant tolerance to biotic and abiotic stresses. AMS also contributes to many ecosystem functions, improving soil aggregation, lowering fertilizer requirements, and reducing nutrient losses.