Progress in the elucidation of the mechanisms of arbuscular mycorrhizal fungi in promotion of phosphorus uptake and utilization by plants

Phosphorus is one of the most important nutrients for plant growth and development, and it is also indispensable for plant metabolism. Deficiency of P greatly limits crop growth in one-third to one-half of cultivated land in China. Symbiotic association between plants and arbuscular mycorrhizal fungi (AMF) is widespread, and is of particular importance to improving plant P uptake efficiency. This paper summarizes progress in the elucidation of the mechanisms of mycorrhizal fungi in the promotion of phosphorus uptake and utilization by plants, including aspects of mycorrhizal morphological features, physiology, biochemistry, and molecular biology. In addition, we discuss research on the potential of growth-promoting mechanisms of mycorrhizal fungi. AMF can form a dense network of hyphae in rhizosphere soil and root cortical cells, increase the absorptive surface areas of the root system, reduce nutrient transport distances, excrete phosphatase, organic acid, and protons, and dissociate insoluble phosphate and the specific expression of phosphate transporter genes.