Calcium signaling controls early stage biofilm formation and dispersal in <i>Vibrio fischeri</i>

Biofilm formation and dispersal are critical steps in both symbiotic and pathogenic colonization. Relative to biofilm formation, the process of dispersal in the model symbiont <i>Vibrio fischeri</i>, and other bacteria, is understudied. Here, we adapted an imaging assay to study early biofilm formation and the dispersal process in <i>V. fischeri</i>. We demonstrated that our assay can quantify biofilm formation and dispersal over time, can reveal phenotypic differences in diverse natural wild-type isolates, and is sensitive enough to investigate the impact of environmental factors. Our data confirm that calcium is a potent biofilm formation signal and identify the diguanylate cyclase CasA as a key regulator. This work leads the way for more in-depth research about unknown mechanisms of biofilm dispersal.