Advances in research on activation of mineral nutrients by arbuscular mycorrhizal fungi

Arbuscular mycorrhizal fungi (AMF) form mutualistic symbioses with a wide diversity of plants to promote the growth of plants by increasing uptake of water and nutrients. The symbiosis between arbuscular mycorrhizal fungi and plants can promote the release of mineral nutrients, boost soil nutrients bioavailability, and improve plant nutrition. Such symbiosis may not only accelerate minerals (basalt, feldspar, granite, pho-sphate minerals) weathering to release nutrients from minerals, but also actively release phosphorus and other nutrients from soil and help plant growth. The mechanism of AMF activating mineral nutrient is mainly because AMF can form mycelium network so that mycorrhizal hyphae transfer mineral nutrients from soil to plant. Mycorrhizal fungi secrete various enzymes which can mineralize soil and release nutrient. Mycorrhizal fungi can also reduce soil pH, activate nutrients in soil. Moreover, mycorrhizal fungi promote microbial activity in soil and regulate nutrient transporter protein. The mineral nutrients activation of AMF is influenced by a number of factors, such as the presence of different types of minerals and soils, species of mycorrhizal fungi and symbiotic plant, as well as carbon source distribution. AMF biotechnology is a potential mechanism to significantly improve the ecological restoration of degraded soils. In the future, we should study the mechanism of arbuschular mycorrhizal fungi to activate mineral nutrients, screen predominant mycorrhizal fungi in degraded soils, enhance research on microbial fertilizers.