Key Microorganism Alleviate Continuous Cropping Obstacles of Polygonatum

Background and Aims Polygonatum odoratum , a widely cultivated and valuable medicinal herb in China, is severely restricted by continuous cropping obstacles (CCOs). Traditional mitigation strategies including crop rotation and chemical control are either inefficient or environmentally unfriendly, lacking sustainable and eco-friendly solutions. This study aimed to analyze the microbiome of continuous cropping P. odoratum , identify key functional microbial taxa, and construct a synthetic microbial community (SynCom) for relieving CCOs. Methods Rhizosphere soil, root endophytic tissues and rhizome samples of P. odoratum with different planting years were collected from three major producing areas, followed by multi-omics analysis to screen core beneficial microbes. A targeted SynCom was assembled, and pot and field experiments were conducted to verify its control effect on CCOs. Results Continuous cropping significantly depleted soil nutrients, reduced soil phosphatase and nitrite reductase activities by 64.73% and 34.87%, respectively. The Chao1 index of rhizosphere bacterial α-diversity decreased by 8.41%, and the relative abundance of the key functional genus Streptomyces dropped sharply by 83.70%. The assembled SynCom effectively alleviated CCOs by restoring rhizosphere microbial homeostasis, improving soil nutrient availability, suppressing rhizome rot, and enhancing the yield and medicinal quality of P. odoratum . Conclusions The loss of Streptomyces is the core microbial factor triggering P. odoratum CCOs. Supplementing core functional microbiota via SynCom mitigates CCOs through synergistic effects of pathogen antagonism, microbial community restoration and soil fertility improvement. This study provides a novel paradigm for relieving CCOs in medicinal plants.