FIG 8.

Model of T6SS-mediated killing during symbiosis establishment. (Left) A single crypt space (light gray oval) initially colonized by a cell of a T6SS-positive V. fischeri strain type (green) and a cell of a V. fischeri strain type susceptible to the T6SS (blue). (Center) Clonal expansion of each strain type results in contact between cells, which promotes T6SS-mediated interactions. (Top inset) T6SS-mediated killing of T6SS-susceptible cells. (Bottom inset) Survival of T6SS-positive cells after a T6SS-mediated attack. (Right) As a result of continued clonal expansion of the population, the crypt space harbors only the T6SS-positive strain type during symbiosis.