Plant growth-promoting rhizobacteria enhance active ingredient accumulation in medicinal plants at elevated CO2 and are associated with indigenous microbiome

It was found that the yield and active ingredient polysaccharides accumulation in the tuber of <i>P. heterophylla</i> were significantly increased by 38 and 253%, respectively. This promotion has been associated with increased root development and changes in the indigenous microbial community. Metagenomics analysis revealed a significant reduction in pathogenic <i>Fusarium</i> abundance in the rhizosphere. Potential biocontrol bacteria <i>Actinobacteria</i> and <i>Proteobacteria</i> were enriched, especially the genera <i>Bradyrhizobium</i> and <i>Rhodanobacter</i>. The reshaping of the rhizosphere microbiome was accompanied by the upregulation of biological pathways related to metabolite biosynthesis in the rhizosphere. These modifications were related to the promotion of the growth and productivity of <i>P. heterophylla</i>. Our findings highlighted the significant role played by PGPR in medicinal plant yield and active ingredient accumulation when exposed to eCO₂.