Background The soil disease-suppressiveness may depend on complex interactions between pathogens and microbiome in response to limiting nutrients. However, these interactions remain poorly understood. Thus, we investigated the significance of soil available phosphorus (AP) in modulating pathogen-microbiome interactions for the emergence or suppression of peanut wilt using receiver operating characteristic curve (ROC) analysis and structural equation modeling (SEM) approaches.
Results We observed significant differences in the relative abundance of pathogenic and beneficial microbes, alpha- and beta-diversity indices between disease-conducive and -suppressive soils. The pathogenic ( Ralstonia) and beneficial ( Burkholderia and Bacillus ) taxa dominated the rhizosphere of wilted and healthy peanut plants. The rhizosphere of healthy rather than wilted plants showed significantly higher microbial biodiversity. Moreover, co-occurrences between Ralstonia and microbiome species were highly positive and negative in the disease-conducive and -suppressive soil, respectively, thus predicting facilitative ( Rudaea ) and suppressive ( Burkholderia , Enterobacter , Bacillus ) role of indigenous microbes in Ralstonia invasion in soil. Moreover, both ROC and SEM analyses revealed that Ralstonia invaded rhizospheric microbial networks and caused peanut wilt, very likely by competently utilizing soil phosphorus under copiotrophic (high AP) than oligotrophic (low AP) conditions.
Conclusion Our results suggest the importance of soil phosphorus availability in altering the interactions between pathobiome and beneficial microbiome. Our study concludes that feeding soil with labile nutrients could deplete microbial biodiversity and interactions while paving the way for pathogen invasion.