The WT-GASP community on semi-solid agar plates. a WT-GASP competition on semi-solid plates (LB + 0.5% agar) inoculated at a 1:1 ratio. On semi-solid agar, E. coli engage in collective swarming motility. The swarming edge of colonies inoculated with a 1:1 mixture of WT and GASP cells (left bottom and right top) consists exclusively of GASP cells, indicating that GASP cells have a large competitive advantage over WT cells on semi-solid agar. Controls, WT/WT (left top) and GASP/GASP (right bottom), show yellow colonies, indicating that the fluorescent reporters are neutral. All scale bars indicate 3 mm. b GASP fraction at day 0 and 3 for GASP starting fractions of 0.1 (red bars
\(n\) = 2) and 0.5 (black bars
\(n\) = 6). For both initial conditions the GASP strain outcompetes the WT.