Spatiotemporal dynamics of culturable endophytic microorganisms in Peucedanum praeruptorum Dunn and screening for plant growth-promoting strains.

Peucedani Radix is the dried root of Peucedanum praeruptorum Dunn (Apiaceae), which is traditionally used for relieving cough and asthma, eliminating phlegm, dispersing wind, and clearing heat. Previous studies on endophytes associated with Peucedanum praeruptorum were largely restricted to specific plant compartments and lacked a comprehensive assessment of endophytic communities across different organs and developmental stages of P. praeruptorum. To investigate the spatiotemporal distribution of endophytic microorganisms in Peucedanum praeruptorum Dunn and assess their potential as plant growth-promoting (PGP) resources, root, stem, and leaf samples were collected from September to December 2024. Endophytic microbial community structures were analyzed using high-throughput sequencing, combined with culture-dependent isolation to screen functional strains, and the growth-promoting strains were co-cultivated with Arabidopsis thaliana and P. praeruptorum to verify their growth-promoting effects. A total of 2,592 fungal and 6,705 bacterial amplicon sequence variants (ASVs) were obtained, with 173 fungal and 39 bacterial strains successfully isolated. The endophytic microbial communities exhibited significant spatiotemporal heterogeneity, with the highest diversity observed in September. Additionally, community composition differed markedly among tissues, particularly between roots and aboveground organs (stems and leaves). Proteobacteria and Ascomycota were identified as the dominant bacterial and fungal phyla, respectively. Several strains possessing PGP traits, including phosphate solubilization, and potassium solubilization, were successfully screened. The validation results of growth-promoting effects indicated that some strains could significantly promote the growth of both A. thaliana and P. praeruptorum. This study elucidates the community characteristics and functional potential of endophytes in P. praeruptorum, providing a theoretical basis and valuable microbial resources for ecological cultivation and microbial inoculant development.