Structural equation model linking siderophore production, siderophore-mediated interactions, and biomass with pathogen abundance and disease incidence (AUDPC) of plant bacterial wilt. Siderophore production, siderophore-mediated interactions in supernatant experiments, and biomass were major contributors to pathogen abundance in co-culture experiments. In the rhizosphere invasion experiment, siderophore-mediated interactions were crucial for the spread of bacterial wilt disease. R2 denotes the proportion of variance explained. The numbers on the arrows denote indicate the effect size of the relationship. The width of the arrows is proportional to the strength of path coefficients. Asterisks (*) indicate significant correlation (*P < 0.1, **P < 0.05, ***P < 0.01).