Study on the diversity, structure, and function of endophytic bacteria in seeds of genuine medicinal plants in gansu province.

backgroundSeeds harbor diverse endophytic bacterial communities that are critical for seed health and plant fitness, however, their functional potential in medicinal plants remains underexplored. This study employed integrated high-throughput sequencing and culturomics to characterize the endophytic bacterial communities in seeds of 10 endemic medicinal plants from Gansu, China, and evaluate their roles in germination enhancement.

resultsWe identified 26,167 bacterial OTUs, with 19 core OTUs consistently present across all samples. The dominant phyla were Proteobacteria, Firmicutes, Bacteroidota, and Actinomycetota, collectively comprising over 80% of relative abundance. Plant species identity was the primary factor shaping bacterial community structure. Among 89 isolated endophytic bacterial strains, 72% exhibited multiple plant growth-promoting (PGP) traits in vitro, including indole-3-acetic acid (IAA) synthesis, siderophore production, phosphate solubilization, and nitrogen fixation. Preliminary validation experiments using wheat (Triticum aestivum ‘Jimai 22’) under controlled conditions indicated that seed-derived Bacillus and Pseudomonas strains significantly promote radicle elongation and improve vigor indices under saline-alkaline stress compared to axenic controls.

conclusionsThese findings highlight medicinal plant seeds as reservoirs of culturable bacteria with multifunctional PGP capabilities. The host-specific community patterns and the in vitro PGP traits suggest these isolates warrant further investigation as potential candidates for bioinoculant development, pending validation on the host medicinal plants themselves.