Research Progress on Arbuscular Mycorrhizal Fungi-mediated Selenium Uptake, Transport, and Metabolism in Plants.

Selenium (Se) is an essential micronutrient for human health, playing a crucial role in antioxidant defense and immune regulation. However, the uneven global distribution of bioavailable Se in soils has led to widespread dietary Se deficiency, posing a potential public health risk. Although plants are the primary dietary source of Se, their intrinsic capacity for Se enrichment is limited. This necessitates the exploration of microbial-assisted strategies for enhancing Se biofortification. Arbuscular mycorrhizal fungi (AMF) are keystone symbionts in the plant-soil continuum and are known to significantly improve plant nutrient acquisition. Nevertheless, the molecular mechanisms underlying AMF-mediated Se metabolism in plants remain incompletely understood. This review systematically summarizes extant knowledge on the molecular regulation of AMF-mediated Se uptake, transport, and assimilation in plants, with a focus on symbiotic signal perception, Se transport networks, Se speciation, and their integrated roles in plant stress responses. The aim is to provide a theoretical foundation for the development of Se-rich agriculture through biological approaches and for breeding crops with enhanced stress tolerance. Furthermore, this review provides insights into the sustainable advancement of agroecological restoration and functional agriculture.