B. Genetic interactions of nlpI with EPase genes. Strains were arrayed using a Rotor HDA replicator on Lennox LB agar plates and incubated for 12 h at 37°C. Each plate contained 384 colonies, 96 from the wildtype, single mutants and double mutants. An example of a 384 plate is shown. Double mutants were made twice, swapping the resistance markers to the two single mutants. Colony integral opacity was quantified as a fitness readout, using the image analysis software Iris (Kritikos et al., 2017). Bar plots shows the averaged values of 2 biological experiments, each having 96 technical replicates (i=2, n=192). The error bars represent the 95% confidence interval. 