Data from: Competition for iron shapes metabolic antagonism between Bacillus subtilis and Pseudomonas

Siderophores have long been implicated in sociomicrobiology as determinants of bacterial interrelations. For plant-associated genera like Bacillus and Pseudomonas, siderophores are often acclaimed for their function in biocontrol. Here, we set out to determine the functional role of the Bacillus subtilis siderophore bacillibactin in an antagonistic interaction with Pseudomonas marginalis. The presence of bacillibactin strongly influences the outcome of the interaction in an iron-dependent manner. A bacillibactin producer B. subtilis restricts the colony spreading of P. marginalis, repress the transcription of histidine kinase-encoding gene gacS, and thereby abolish production of secondary metabolites such as pyoverdine and viscosin. In contrast, the lack of bacillibactin restricts B. subtilis colony growth in a mechanism reminiscent of a siderophore tug-of-war for iron. Our study identifies a Bacillus-Pseudomonas interaction conserved across fluorescent Pseudomonas spp., expanding our understanding of the interplay between two genera of the most well-studied soil microbes.