Research Progress on the Diversity, Functions, and Applications of Endophytes in Panax ginseng

Endophytes of Panax ginseng are symbiotic microbes colonizing internal tissues asymptomatically, forming a core component of the ginseng microecosystem through co-evolution. This review summarizes recent progress on ginseng endophytes, covering community diversity, ecological functions, and application prospects. Culturable endophytic fungi span over 40 genera, dominated by Ascomycota, while endophytic bacteria mainly belong to Firmicutes, Proteobacteria and Actinobacteria. Research methodologies have advanced from culture-based isolation to high-throughput amplicon sequencing and ASV-based profiling. Functionally, approximately 78% of culturable isolates produce indole-3-acetic acid, and strains with phosphate-solubilizing, nitrogen-fixing and siderophore-secreting activities are widely identified. For biocontrol, Paenibacillus and Burkholderia strains show broad-spectrum antagonism against 5-8 common ginseng pathogens, with Bacillus strains achieving 61.45%-80% mycelial inhibition. Over 10 endophytic species can synthesize ginsenosides or convert common ginsenosides into rare monomers like Rg2, Rb3, and compound K, with some elicitor strains increasing total ginsenoside contents in adventitious roots up to fourfold. Ginseng endophytes show great potential as microbial fertilizers and biocontrol agents for sustainable ginseng cultivation, biocatalysts for rare ginsenosides production, and sources of novel bioactive lead compounds for drug discovery. Current challenges, including the abundance of unculturable microbiota, unclear host-microbe interactions, and inconsistent field efficacy are discussed, along with future research directions.