Endophytes-mediated structural remodeling of polysaccharides and small molecules in aging Artemisia argyi leaves

Traditional aging of Artemisia argyi leaves significantly enhances its medicinal value, but the underlying macromolecular mechanism is unclear. Here, we employed an integrated multi-omics approach to investigate how microbial succession drives polysaccharide remodeling and bioactive compound changes during Artemisia argyi leaves aging (0-5 years). Our findings demonstrated that Actinobacteria and Aspergillus dominate the initial polysaccharide degradation phase, while Pseudomonas promotes glucan accumulation in later stages. The polysaccharides undergo a structural transformation from pectin-type to glucan-type. Monosaccharide composition analysis indicated that the galacturonic acid (Gal-UA) content dropped sharply from 18.18% to 3.47%, while glucose (Glc) increased from 10.27% to 38.52% over five years. SEC-MALLS analysis revealed that the weight-average molecular weight (Mw) peaked at 159.8 kDa after one year of aging before decreasing. Metabolomic analysis revealed significant correlations between phenolic acids and Paradissoconium, as well as between terpenoids and Wallemia (r > 0.9). Correlation network analysis further showing positive associations between neutral sugars and phenolics, and negative correlations between acidic sugars and terpenoids. This study first elucidates the synergistic "microbiota-polysaccharide-metabolite" mechanism during Artemisia argyi aging, providing molecular evidence for the traditional "longer aging yields better efficacy" and offering a theoretical basis for process optimization and production standardization.