Taxonomy of <i>Pseudomonas</i> spp. determines interactions with <i>Bacillus subtilis</i>

There is a strong interest in the microbial ecology field to predict interaction among microorganisms, whether two microbial isolates will promote each other's growth or compete for resources. Numerous studies have been performed based on surveying the available literature or testing phylogenetically diverse sets of species in synthetic communities. Here, a high throughput screening has been performed using 720 <i>Pseudomonas</i> isolates, and their impact on the biofilm formation of <i>Bacillus subtilis</i> was tested. The aim was to determine whether a majority of <i>Pseudomonas</i> will promote or inhibit the biofilms of <i>B. subtilis</i> in the co-cultures. This study reports that <i>Pseudomonas</i> taxonomy is a good predictor of interaction outcome, and only a minority of <i>Pseudomonas</i> isolates promote <i>Bacillus</i> biofilm establishment.