Harnessing AMF-plant-microbe systems for heavy metal remediation

Soil heavy metal pollution poses a global environmental threat, demanding effective and sustainable remediation strategies. Arbuscular mycorrhizal fungi (AMF) play a multifaceted role in enhancing the remediation of heavy metal (HM)-contaminated soils through extensive hyphal networks that interact with plant roots and soil microbiota. AMF hyphae and their exudates, such as glomalin, directly immobilize metal ions and reduce bioavailability by modifying soil properties (e.g., pH). Furthermore, AMF reshape the rhizosphere microbiome by enriching metal-tolerant bacteria (e.g., Pseudomonas, Bacillus) and fostering synergistic microbial communities via cross-kingdom signaling. Within plants, AMF symbiosis-especially with hyperaccumulators-optimizes root architecture, enhances nutrient and water uptake, stimulates biomass production, and regulates key physiological and molecular responses. These include bolstering antioxidant defenses, maintaining photosynthetic efficiency, and upregulating genes involved in metal transport, compartmentalization, and stress signaling. Field studies confirm the potential of AMF-hyperaccumulator systems in metal extraction and stabilization. However, transitioning from controlled experiments to field applications remains challenging due to the complexity of multipartite interactions and a lack of predictive frameworks. This review critically integrates interdisciplinary insights into a forward-looking perspective, emphasizing the need to shift from empirical approaches to an intelligent, predictive design paradigm. We propose leveraging machine learning to decode interactions among AMF genotypes, plant phenotypes, microbial consortia, and soil properties, enabling the rational design of efficient remediation systems. Ultimately, overcoming barriers to field implementation requires integrating robust science with advanced engineering and supportive policy frameworks.