Reciprocal signaling between quorum sensing mutants: A model for division of labor.

Division of labor, the specialization of subsets of individuals in complementary tasks, increases population efficiency and fitness. We explored swarming motility in Pseudomonas aeruginosa quorum sensing mutants as a model for studying the division of labor. Deletion of the signal synthesis genes lasI or rhlI disrupts swarming, but co-culturing ΔlasI and ΔrhlI restores it in a density-dependent manner. This indicates a successful division of labor where ΔrhlI produces the signal necessary for the ΔlasI mutant, and the ΔlasI reciprocates. We used RNA sequencing to identify additional genes potentially involved in division of labor. Our findings underscore P. aeruginosa swarming as a tractable bacterial model for the division of labor among cells-a hallmark of differentiated multicellularity.