Recent advances in the studies of nutrient transportation, metabolism, utilization and regulation in arbuscular mycorrhizas

Arbuscular mycorrhizas (AM) are mutualistic associations between Glomeromycota fungi and host plant roots. The processes involving transportation, metabolism, utilization and regulation of both inorganic and organic nutrients are the foundation of the symbionts, which are the critical physiological mechanisms of the mutual relationship between the AM fungi and host plants. The characteristics of the transportation and metabolism of nitrogen or carbon have been well documented in the literature. However, the latest progress on comprehensive and systematic review in relation to the studies of nutrient transfer, metabolism, utilization and regulation in AM associations remain unavailable. This review aims to introduce the nutrient-exchange forms and spatiotemporal characteristics between AM fungi and host plants, and summarize the characteristics of nutrient transport, metabolism and utilization and their regulatory mechanism in AM associations. The advances and prospects of the studies in this research topic are discussed. This study may enhance our understanding of the physiological mechanisms of the mutualisms between AM fungi and host plants, and promote future study in this research area.