Abstract: The rhizobiont represents a highly synergistic and dynamically interacting life system composed of plants, roots, the rhizosphere, mycelium, soil, and associated microorganisms. Within this cross-species network, plants regulate rhizosphere microbial metabolism through root exudates, while microorganisms activate and transform soil nutrients, feeding back to the plants. Together, they form a multi-level, multi-interface, cascaded interaction network that jointly governs nutrient transformation, spatial migration, and plant nutrient uptake efficiency. With the ongoing transformation of agriculture toward green, efficient, and energy-saving practices, establishing a highly efficient synergistic system integrating plants, microorganisms, and soil—based on the theory of the rhizosphere life community—has become a key strategy for promoting nutrient utilization efficiency, ensuring food security, and mitigating environmental risks. Developing new green and intelligent products founded on this theory has thus emerged as a frontier challenge in plant nutrition research and product innovation. Iron (Fe), an essential micronutrient for plants, plays a vital role in physiological processes such as photosynthesis, respiration, and electron transport. Its effective supply directly influences photosynthetic efficiency, energy metabolism, yield, and crop quality. In recent years, theoretical advances and product innovations in plant−microbe synergistic enhancement of iron nutrition have progressed rapidly, providing new pathways for developing green and intelligent bio-based chelating agents and improving both plant iron nutrition and human health. Using a maize/peanut intercropping system as a model, this study systematically elucidates the mechanisms through which plant−plant and plant−microbe interactions enhance iron nutrition. From theoretical analysis and mechanistic validation to product development, the work demonstrates the scientific validity, necessity, and feasibility of the rhizosphere community theory in improving crop iron nutrition. At the theoretical level, the study reveals that maize roots secrete mugineic acid family phytosiderophores (MAs), such as 2’-deoxymugineic acid (DMA), which form soluble Fe(Ⅲ)−DMA chelates that can be absorbed by peanut roots. This process alleviates peanut iron deficiency and achieves “resource sharing” between species, thereby challenging the traditional view that dicotyledonous plants acquire iron solely via reduction mechanisms. Simultaneously, the intercropping system enriches functional microbial communities, including siderophore-producing genera such as Pseudomonas. These microbes exhibit strong siderophore synthesis capacities under iron-deficient conditions. By secreting microbial siderophores (e.g., pyoverdine), they significantly enhance soil iron bioavailability, promote plant iron uptake and yield, and form a coordinated regulatory network for plant−microbe synergistic iron acquisition. In terms of product development and application, building upon the discovery of maize-secreted phytosiderophores, a derivative compound—PDMA—has been successfully developed to address the instability, easy degradation, and high cost of natural DMA. PDMA possesses a more stable molecular structure and exhibits multiple functions, including improving iron bioavailability, promoting crop iron uptake, and modulating rhizosphere microbial communities, thus showing strong application potential. Meanwhile, the diversity and structural complexity of microbial siderophores present both challenges and opportunities for further exploration and utilization of siderophore-producing microorganisms. In conclusion, the maize/peanut intercropping system exemplifies how plant−microbe−soil interactions within the rhizosphere community can enhance iron nutrition. This case provides not only a new paradigm linking rhizosphere community theory and product innovation but also theoretical support and technological pathways for advancing global green agricultural sustainability and food security.