Multidimensional Regulatory Mechanisms of Arbuscular Mycorrhizal Fungi on the Migration and Transformation of Heavy Metals in Soil

Abstract

With the rapid development of industrialization and urbanization, soil heavy metal pollution has become a global ecological environment and health problem. Heavy metals such as Cd, Pb, and Hg enter the soil environment through mining, industrial emissions, and agricultural activities, and pose a serious threat to soil ecological function, food security, and human health due to their concealment, refractory degradation, and bioaccumulation. Traditional remediation technologies have limitations such as high cost and high risk of secondary pollution, while bioremediation technologies have attracted extensive attention due to their eco-friendliness and sustainability. Among them, AMF has shown significant potential in the remediation of heavy metal contaminated soil by forming a symbiotic system with plants. In this paper, we systematically reviewed the regulatory mechanism of AMF-plant symbiosis system on the migration and transformation of heavy metals, including the multi-dimensional effects of physical barrier, chemical fixation and biotransformation. At the physical level, AMF promotes the formation of soil aggregates through hyphal network and balloon-related soil protein (GRSP), which effectively intercepts heavy metal ions. At the chemical level, AMF changes the occurrence form of heavy metals and reduces their bioavailability by secreting organic acids, regulating rhizosphere pH and redox potential (Eh). In addition, the effects of environmental factors such as soil characteristics, climatic conditions and agricultural activities on the colonization and remediation efficiency of AMF have also been deeply explored. This paper provides a theoretical basis for the application of AMF in the remediation of heavy metal contaminated soil, and looks forward to future research directions, including efficient strain screening, field technology optimization, and analysis of multi-factor collaborative regulation mechanism. The synergistic regulatory mechanism mediated by it and the derived rhizosphere multi-dimensional restoration system can significantly improve the expression of plant stress resistance genes and reduce the bioavailability of heavy metals, which is an irreplaceable long-term solution in the current heavy metal pollution control.