Metabolomic insights into rhizosphere microbial dynamics in desert plants under drought stress

Drought hinders plant growth and development. However, studies on rhizospheric metabolism and microbial composition of desert plants under drought stress are limited. This study used untargeted metabolomics to detect that the differential metabolites included mainly alkaloids and their derivatives, benzenoids, lipids, and lipid molecules under drought stress. A Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that the differences between drought stress in the rhizosphere environment were usually reflected in microbial metabolism, plant hormone biosynthesis, and secondary metabolite biosynthesis in different environments. Metagenomic analysis showed that the relative abundances of Chloroflexi, Firmicutes, and Gemmatimonadetes in the mild drought rhizosphere group (MiR) were significantly higher than those in the severe drought rhizospheric soil group (SR) in the phylum of the microorganisms; the relative abundance of Proteobacteria in the SR group was also significantly higher. Through the analysis of the correlation network, it is found that there is a significant correlation between microorganisms and differential metabolites. During drought stress, plants can indirectly influence the support of soil microbes by modifying the structure and concentration of metabolites, which helps to enhance drought tolerance. This study provides a theoretical basis for exploring new stress adaptation strategies and protecting soil microecology.