Root exudate-mediated nutrient exchange in the rhizosphere: multi-element networks, dynamic regulation, and implications for sustainable agriculture

BACKGROUND: Over hundreds of millions of years of co-evolution, plants and microbes have co-optimized nutrient exchange strategies at the rhizosphere-the core interface for chemical communication-leading to highly diverse and sophisticated patterns. Although recent studies have partially clarified the mechanisms underlying carbon-nitrogen, carbon-phosphorus, and other nutrient exchange processes between plant roots and microbes, a systematic understanding of these nutrient exchange strategies remains insufficient. AIM OF REVIEW: This review synthesizes recent research findings on root metabolites and plant-microbe nutrient exchange, analyzes the collaborative mechanisms of key nutrient elements (nitrogen, phosphorus, potassium) in the rhizosphere, explores the dynamic response characteristics of multi-element interaction networks to stresses such as drought, salinity and pathogens, and discusses the implications of these processes for plant environmental adaptability. Additionally, it summarizes advanced technologies applied in rhizosphere nutrient research and outlines future research directions, thereby providing a theoretical basis for understanding the functional mechanisms of rhizosphere ecosystems and promoting the development of sustainable agriculture. KEY SCIENTIFIC CONCEPTS OF REVIEW: Root exudates act as both chemical signals for cross-kingdom communication and metabolic resources. Via root exudate-mediated carbon allocation mechanisms, plants and microbes construct multidimensional interaction networks in the rhizosphere. These networks involve both macronutrients (nitrogen, phosphorus, potassium) and micronutrients (sulfur, iron, zinc), with synergistic regulation between elements. The co-evolved nutrient exchange strategies are highly diverse and precise. They not only regulate nutrient exchange via element interaction networks but also dynamically adjust to plant growth stages, soil conditions, and stresses (e.g., drought, salinity, pathogens). This dynamic adjustment helps plants overcome soil nutrient limitations, thereby enhancing their adaptability to complex environments.