The fungal root endophyte Serendipita vermifera displays inter-kingdom synergistic beneficial effects with the microbiota in Arabidopsis thaliana and barley

Plant root-associated bacteria can confer protection against pathogen infection. By contrast, the beneficial effects of root endophytic fungi and their synergistic interactions with bacteria remain poorly defined. We demonstrate that the combined action of a fungal root endophyte from a widespread taxon with core bacterial microbiota members provides synergistic protection against an aggressive soil-borne pathogen in Arabidopsis thaliana and barley. We additionally show early inter-kingdom growth promotion benefits which are host and microbiota composition dependent. HighlightsO_LIThe root endophytic fungus Serendipita vermifera can functionally replace core bacterial microbiota members in mitigating pathogen infection and disease symptoms. C_LIO_LIS. vermifera additionally stabilizes and potentiates the protective activities of root-associated bacteria and mitigates the negative effects of a non-native bacterial community in A. thaliana. C_LIO_LIInter-kingdom synergistic beneficial effects do not require extensive host transcriptional reprogramming nor high levels of S. vermifera colonisation. C_LIO_LIInter-kingdom protective benefits are largely independent of the host while synergism leading to early inter-kingdom growth promotion is driven by host species and microbiota composition. C_LI