Plant-microbe interactions influence plant performance via boosting beneficial root-endophytic bacteria

Salvia miltiorrhiza is a highly valuable medicinal plant and its cultivation is constrained by limited suitable land. Long-term continuous cropping practices alleviate limitations in planting area as well as causes the decline in plant yield and quality. Endophytic microorganisms colonize inside plant roots and are known to play important roles in improving the performance of model plants (such as Arabidopsis thaliana) and food crops (such as wheat, soybean, rice and maize). However, the understanding of how medicinal plants with different growth status (i.e., healthy and disease) shape the assembly of root-endophytic microorganisms and the functional importance of these microorganisms in improving plant performance remains largely unknown.

Here, we investigated the assembly of root-endophytic microorganisms in medicinal plants with different growth status and its links with plant performance improvement. We found that medicinal plants with different growth status had distinct root-endophytic bacterial communities. Healthy plant roots recruited some potentially beneficial bacteria partners, particularly Pseudomonas into the endosphere. We further investigated the functional importance of these potentially beneficial bacteria on plant performance in subsequent greenhouse and field experiments. We found that root-endophytic Pseudomonas effectively increased medicinal plant seedling growth, crop yield, and the content of effective medicinal components.

Taken together, we demonstrate that healthy medicinal plants can form a distinct root-endophytic bacterial community, leading to an increase in plant growth-promoting endophytic bacteria (PGPEB) that contribute to the improvement of crop growth and quality. Our research provides valuable insights into the significant role of PGPEB in enhancing crop growth and improving medicinal plants quality for human health development in the future.