THE ROLE OF A SUBPOPULATION OF MOTILE CELLS IN BACILLUS BIOFILMS DURING INTERSPECIES INTERACTION

Bacillus subtilis biofilms contain a small subpopulation of motile cells, whose role was so far unknown. When B. subtilis is grown alone, this motile cells subpopulation plays only a minor part in shaping the biofilm architecture. In contrast, upon interspecies interaction, the motile cells subpopulation acts as cavalry that enables the encirclement of the rival biofilms (Gili Rosenberg In press). Once the foreign biofilm is surrounded, B. subtilis cells secret a mixture of toxins in order to eliminate competitor Bacilli species. The toxins secretion is reinforced by yet another subpopulation of cells that produces and secretes high levels of the toxic molecules. We found that the elevation in toxin production is a result of a loss of B. subtilis native plasmid in those cells. We now investigate the exact physical and chemical triggers that promote the activation of the motile subpopulation in the biofilm. So far, we found that the surface area parameters of the engulfed territories, as well as the chemical composition of the surface, play a cardinal role on the movement strategy used by B. subtilis biofilms.

Gili Rosenberg, Yaara Oppenheimer-Shaanan, Tzvia Olender, Shany Doron, Julius Ben Ari, Alexandra Sirota-Madi, Zohar Bloom-Ackermann and Ilana Kolodkin-Gal (In press). Not so simple, not so subtle: The interspecies competition between Bacillus simplex and Bacillus subtilis and its impact on the evolution of biofilms. npj Biofilms and Microbiomes.