Fig. 7
From: Interactions with native microbial keystone taxa enhance the biocontrol efficiency of Streptomyces
The diagram illustrates the enhanced inhibition of Streptomyces R02 on Ralstonia solanacearum Rs1115 through interactions with Stenotrophomonas maltophilia CSC98 and Paenibacillus cellulositrophicus CSC13 in soil. S. maltophilia CSC98 and P. cellulositrophicus CSC13 demonstrated a mutually facilitative relationship, where each species promoted the growth and/or activity of the other. Similarly, P. cellulositrophicus CSC13 and Streptomyces R02 also exhibited mutual facilitation, with both species benefiting from their interaction. Under this facilitation, Streptomyces R02 exhibited stronger inhibition of R. solanacearum Rs1115, compared to when CSC13 was absent. This inhibition was attributed to the CSC13-induced production of bioactive secondary metabolites in Streptomyces R02, Erythromycin E, which we confirmed to directly inhibit R. solanacearum on nutrient agar and in nutrient broth. The induction of Erythromycin E in Streptomyces R02 by CSC13 was associated with the upregulation of key genes across five major genetic pathways. In contrast, S. maltophilia CSC98 and R. solanacearum Rs1115 displayed nutritional competition, resulting in a negative interaction likely due to competition for shared resources and limiting their growth potential. The microbial interaction model reveals the critical role of Streptomyces R02 and its interactions with two bacterial strains in controlling against a major plant pathogen, mediated by upregulations of key genes and a metabolite in the Streptomyces