Rhizosphere microorganisms are the main factors affecting the formation of high quality medicinal materials and promoting the accumulation of secondary metabolites. However, the composition, diversity, and function of rhizosphere microbial communities in endangered wild and cultivated Rhizoma Atractylodis Macrocephalae (RAM) and their relationships with active component accumulation have remained unclear. In this study, high-throughput sequencing and correlation analysis were used to study the rhizosphere microbial community diversity (bacteria and fungi) of three RAM species and its correlation with the accumulation of polysaccharides, atractylone, and lactones (I, II, and III). A total of 24 phyla, 46 classes, and 110 genera were detected. The dominant taxa were Proteobacteria, Ascomycota, and Basidiomycota. The microbial communities in both wild and artificially cultivated soil samples were extremely species-rich, but there were some differences in their structure and the relative abundances of microorganism taxa. Meanwhile, the contents of effective components in wild RAM were significantly higher than those in cultivated RAM. Correlation analysis showed that 16 bacterial and 10 fungal genera were positively or negatively correlated with active ingredient accumulation. These results showed that rhizosphere microorganisms could play an important role in component accumulation and might lay a foundation for future research on endangered materials.

Porous starch (PS) is widely used in food, pharmaceutical, and environmental industries for its high adsorption capacity and controlled release properties. To explore how surface gelatinization affected enzymatically prepared PS, corn starch was first modified via surface gelatinization using a CaCl₂ solution and then treated with α-amylase and amyloglucosidase to synthesize PS. Its structural and functional characteristics were subsequently analyzed. The findings demonstrated that the CaCl₂ solution facilitated the surface gelatinization and enhanced the enzymatic hydrolysis of natural starch. The yield, specific volume, water solubility, swelling power, and oil absorption capacity of PS pretreated with CaCl₂ solution were improved. After 40 min of processing, the yield, specific volume, and oil absorption capacity of PS reached the optimal state, increasing by 19.90%, 91.19%, and 32.84%, respectively. Consequently, its fisetin encapsulation efficiency (93.67%) and loading capacity (8.03%) were also higher than those of non-pretreated PS, attributed to the reduced short-range structure and crystallinity in the CaCl₂-pretreated PS. The DPPH and ABTS radical scavenging activities of CaCl₂-pretreated PS/fisetin (PS/FIT) exceeded those of the non-pretreated PS/FIT and free fisetin. These findings highlight the potential of CaCl₂ pretreatment as an effective strategy to enhance the functional properties of enzymatic PS.

This study aimed to explore mechanisms driving differential sesquiterpenoid accumulation in Atractylodes macrocephala rhizome (AMR) under different growth environments. Root and rhizosphere soil samples were collected from wild, imitated wild, one- and two-year cultivated AMR. Combined metabolomic, transcriptomic and microbiomic profiling was carried out to investigate alterations in sesquiterpenoid levels, root-associated microbiota, and terpenoid biosynthetic genes under different growth environments. Metabolomics revealed that wild AMR exhibited higher pyruvate consumption and accumulated more atractylone and atractylenolides. Transcriptomic analysis demonstrated that the genes encoding key MEP pathway enzymes (DXS, DXR, MCT, HDS) and the genes encoding the sesquiterpenoid biosynthetic enzyme GDS were significantly upregulated in wild AMR. In contrast, the genes encoding triterpenoid synthetic enzymes (SQS, SQE, β-AS) were downregulated, redirecting metabolic precursors toward sesquiterpenoid synthesis. Microbial community structures differed substantially across groups. Further analysis suggested rhizosphere microorganisms were important contributors to AMR medicinal quality, and sesquiterpenoid metabolites accumulated in AMR roots, together with the rhizosphere microenvironment, jointly shape specific rhizosphere fungal assembly. This study systematically revealed the synergistic regulatory relationships among sesquiterpenoids metabolism, gene expression, growth environment, and root-associated microbes, providing multi-omics evidence for clarifying the mechanism by which these factors coordinately regulate the quality of AMR.