Pseudomonas can survive bacteriocin-mediated killing via a persistence-like mechanism

Phage tail-like bacteriocins (tailocins) are bacterially-produced protein toxins that can mediate competitive interactions between co-colonizing bacteria. Both theoretical and empirical research has shown there are intransitive interactions between bacteriocin-producing, bacteriocin-sensitive, and bacteriocin-resistant populations, whereby producers outcompete sensitive, sensitive outcompete resistant, and resistant outcompete producers. These so-called rock-paper-scissor dynamics explain how all three populations can be maintained in the same environment, without one genotype driving the others extinct. Using Pseudomonas syringae as a model system, we demonstrate that otherwise sensitive bacterial cells have the ability to survive bacteriocin exposure through a physiological mechanism. This mechanism is similar to the persister phenotype that allows cells to survive antibiotic exposure, without acquiring antibiotic resistance. We show that a significant fraction of the target cells that survive a lethal dose of tailocin did not exhibit any detectable increase in survival in subsequent exposure (i.e. they survived through a persistence-like mechanism). Tailocin persister cells were more prevelant in stationary rather than log ...Continue Reading