Echinacea purpurea microbiota: bacterial–fungal interactions and the interplay with host and non‐host plant species in vitro dual culture

Important evidence is reported on the antimicrobial and antagonistic properties of bacterial endophytes in Echinacea purpurea and their role in the modulation of plant synthesis of bioactive compounds. Here, endophytic fungi were isolated from E. purpurea, and the dual culture approach was applied to deepen insights into the complex plant-microbiome interaction network. In vitro experiments were carried out to evaluate the species specificity of the interaction between host (E. purpurea) and non-host (E. angustifolia and Nicotiana tabacum) plant tissues and bacterial or fungal endophytes isolated from living E. purpurea plants to test interactions between fungal and bacterial endophytes. A higher tropism towards plant tissue and growth was observed for both fungal and bacterial isolates compared to controls without plant tissue. The growth of all fungi was significantly inhibited by several bacterial strains that, in turn, were scarcely affected by the presence of fungi. Finally, E. purpurea endophytic bacteria were able to inhibit mycelial growth of the phytopathogen Botrytis cinerea. Bacteria and fungi living in symbiosis with wild Echinacea plants interact with each other and could represent a potential source of bioactive compounds and a biocontrol tool.