Effects of Endophytic Fungus Setophoma terrestris on Growth of Panax notoginseng and Its Rhizosphere Soil Microorganisms

To investigate the effects of the endophytic fungus <i>Setophoma terrestris</i> (isolated from <i>Panax notoginseng</i> roots) on the growth and rhizosphere microbiota of understory-cultivated <i>P. notoginseng</i>, we prepared liquid and solid fermentates of the fungus and applied them separately via irrigation. Rhizosphere soil of <i>P. notoginseng</i> was subjected to non-targeted metabolomics and microbiome sequencing for detection and analysis. Relative to the control, <i>P. notoginseng</i> treated with liquid and solid fermentates exhibited increases in plant height (3.5% and 0.7%), chlorophyll content (23.4% and 20.4%), and total saponin content (14.6% and 17.0%), respectively. Non-targeted metabolomics identified 3855 metabolites across 23 classes, with amino acids and their derivatives (21.54%) and benzene derivatives (14.21%) as the primary components. The significantly altered metabolic pathways shared by the two treatment groups included ABC transporters, purine metabolism, and the biosynthesis of various other secondary metabolites. Exogenous addition of <i>S. terrestris</i> significantly affected the composition of the rhizosphere soil microbial community of <i>P. notoginseng</i> and increased the relative abundance of genera such as Bradyrhizobium. In conclusion, the endophytic fungus <i>S. terrestris</i> enhances <i>P. notoginseng</i> growth and modulates both rhizosphere soil metabolites and microbial abundance. This study can provide certain data support for research on endophytic fungi of <i>P. notoginseng</i>.