Triterpenoid and steroidal saponins differentially influence soil bacterial genera

Plant specialized metabolites (PSMs) are secreted into the rhizosphere, which is the zone of soil surrounding the roots. They are often involved in root-associated microbiome assembly, but their structure-activity relationships are unknown. Saponins are a group of PSMs that are widely dis-tributed in angiosperms. In this study, we compared the bacterial communities in field soils treated with four different saponins. All saponin treatments decreased bacterial alpha-diversity and caused significant differences in the beta-diversity when compared with the control. Our results indicate that there is a relationship between the chemical structure of saponins and their effects on soil bacterial communities.