Impact of drought on rhizosphere microorganisms and soil environment of Bupleurum chinense

The study investigated the impact of drought on the rhizosphere microorganisms of Bupleurum chinense seedlings. Soil analysis revealed that soil pH, soil organic matter (SOM), and available nitrogen decreased as drought intensity increased, while the response of available potassium (K) and phosphorus (P) was more complex. The activity of peroxidase (POD) decreased, and the activities of superoxide dismutase (SOD) and catalase (CAT) varied under different drought conditions. Amplicon sequencing results showed that moderate drought increased bacterial diversity, while severe drought decreased both bacterial and fungal diversity. Significant shifts in microbial communities were observed, with increases in Proteobacteria and actinomycetes and decreases in Acidobacteria and bifidobacteria under severe drought. As drought intensity increased, ascomycetes increased while basidiomycetes and associated flora decreased. Biomarker analysis identified specific bacterial and fungal taxa associated with different drought treatments. The study also explored the relationship between root-associated microbiota and soil factors, as well as the potential functional implications of observed changes in microbial communities. These findings highlight significant alterations in the rhizosphere microorganisms of B. chinense seedlings under drought stress and provide insights into changes in soil function and their potential impacts on soil sustainability and plant health in the rhizosphere.