Analysis of key nodes and metabolic pathways in the protein network of secondary metabolism in Panax quinquefolius L. enhanced by arbuscular mycorrhizal fungi

Arbuscular Mycorrhizal Fungi (AMF) formed symbiotic relationships with roots and were capable of promoting the growth of the medicinal plant Panax quinquefolius L. as well as the accumulation of its active component, ginsenosides. However, the regulatory mechanisms underlying this process remained unclear. To elucidate the protein signaling pathways through which AMF regulates the secondary metabolism of P. quinquefolius and to promote the application of AMF inoculants in the cultivation of medicinal herbs, this study employed a controlled pot experiment, establishing an AMF-inoculated group along with a control group. Tandem mass tag (TMT) labeling quantitative techniques were utilized for the proteomic analysis of the roots, and these results were utilized to conduct a correlation analysis with the previous transcriptomics and metabolomics data. AMF significantly regulated the growth and protein expression profile of P. quinquefolius, leading to the identification of 214 differentially expressed proteins (DEPs). Gene Ontology (GO) functional enrichment analysis indicated that the DEPs were involved in oxidoreductase activity, ligase activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis showed that pathways related to nitrogen metabolism biosynthesis, carbon fixation in photosynthetic organisms, phenylpropanoid biosynthesis, and pyruvate metabolism were significantly enriched among the DEPs. Additionally, pyruvate kinase was identified as a key network node in protein interactions. Multi-omics analysis revealed that proteins such as S-adenosylmethionine synthetase, involved in cysteine and methionine metabolism, and genes such as CYCD3, related to plant hormone signal transduction, were significantly upregulated, with their expression levels showing a significant positive correlation with ginsenoside accumulation. This study identifies critical nodes and pathways at the protein level through which AMF regulates secondary metabolism in P. quinquefolius, providing foundational data for the expansion of AMF research and application in the field of medicinal herbs.