Intercropping tea plants with Ophiopogon japonicus alters root exudate metabolites and restructures rhizosphere microbiota to promote plant growth

Intercropping tea plants with Ophiopogon japonicus effectively prevents soil erosion and enhances the ecological stability of mountainous tea plantations. However, the underlying ecological facilitation mechanisms remain underexplored. This study investigated the effects of root exudates on rhizosphere soil microbial community structure and tea plant growth under an intercropping system through pot experiments. Results showed that intercropping significantly promoted tea shoot length and plant height. Additionally, rhizosphere microbial diversity increased, with significant changes observed in the microbial community structure. We also analyzed the functional characteristics of the microbiome under different treatments from a microbial functional perspective, such as the enhancement of microbial functions related to glycolysis and cellulose degradation, as well as the enrichment of functional microbes with beneficial genomic traits. Further analysis of root exudate composition under different planting modes revealed that intercropping significantly increased the content of amino acids such as histidine, serine, and leucine in root exudates. KEGG pathway analysis confirmed that metabolic pathways related to amino acid metabolism were significantly enriched, displaying the highest levels of enrichment. These findings highlight the potential of intercropping Ophiopogon japonicus to improve soil ecology and enhance tea plant growth in mountainous plantations.