Rhizosphere Metabolomics Reveals Chemical Communication and Metabolic Reprogramming in Tea Plant‐Forage Legume Intercropping Systems

Intensive tea cultivation faces challenges in fertilizer dependency and soil health. Intercropping with forage legumes offers a sustainable solution, enhancing productivity and environmental sustainability. This study employed rhizosphere metabolomics to investigate chemical communication between tea plants and forage legumes under different intercropping systems, focusing on the below-ground environment. We aimed to identify key differentially abundant rhizosphere metabolites and assess their contribution to soil nutrient dynamics and tea plant resilience. Four planting methods were used: tea monoculture (MT), intercropping without partitions (IT), with plastic partitions (PPIT), and with net partitions (NPIT). Metabolites were analyzed using chromatography-mass spectrometry. Results showed unique metabolic profiles in full-barrier intercropping (PPIT), with increased differentially abundant metabolites, including phenolic compounds, terpenes, and fatty acids (p < 0.05). Forage legume roots exhibited significantly higher secretion levels of coumestrol, a bioactive flavonoid linked to plant-microbe interactions and soil nutrient dynamics. These findings highlight the benefits of intercropping, demonstrating metabolic changes linked to improved soil health and stress tolerance. The upregulation of coumestrol suggests enhanced nitrogen availability. This research provides novel insights into rhizosphere intercropping, promoting sustainable tea production, reducing fertilizer use, and mitigating soil-related biotic and abiotic stress. Increased metabolite diversity reflects intricate interactions governing tea plant health.