Integrated analysis of 16 S endophytic bacteria and non-targeted metabolomics reveals the drought response mechanisms of Portulaca Oleracea L

Drought is currently one of the biggest challenges facing global agricultural production. Purslane (Portulaca oleracea L.) has attracted widespread attention due to its exceptional drought resistance. However, the dynamics in endophytic bacterial communities and their synergistic response mechanisms with metabolites under drought stress in purslane remain poorly understood. The study systematically investigated the dynamic responses of endophytic bacterial communities and metabolites in purslane under drought stress and rehydration conditions through integrating 16 S rDNA sequencing and untargeted metabolomics. Results revealed that drought stress caused no significant changes in purslane’s endophytic bacterial community, whereas rehydration induced a marked restructuring of the microbiota. Co-expression network analysis identified Delftia and Stenotrophomonas were the key hub species in the drought and rehydration groups, respectively. Untargeted metabolomic analysis detected a total of 2,973 metabolites, primarily lipids, lipid-like molecules, and organic acids and their derivatives, which were significantly enriched in pathways such as phenylalanine biosynthesis, amino acid metabolism, and tyrosine metabolism. Integrated random forest modeling and Spearman correlation analysis revealed significant associations between differential bacterial genera and differential metabolites, with Stenotrophomonas showing particularly close links to multiple metabolites. Drought stress did not significantly change the endophytic bacterial community structure in purslane, while rehydration increased diversity and altered the dominant genera. Metabolite levels also shifted significantly under different water conditions. Strong links were found between endophytic bacteria and these metabolic changes. Together, these findings offer new insights into how microbial-metabolite interactions help purslane adapt to water stress.