A. Colony morphologies (4–5 d) of strains bearing markerless in-frame deletions of the three new genes identified in the screen. In the amrZ deletion background, deletions were complemented at the ectopic attB locus. B. Congo red binding by the indicated mutant colonies. Mean values of at least 3 replicates are shown; error bars indicate ± 1 standard deviation. *, p < 0.05; **, p < 0.01; ***, p < 0.001 relative to the leftmost strain in each graph. C. Crystal violet binding by the indicated mutants after 24 h of static culture. Mean values of at least 4 replicates are shown; error bars indicate ± 1 standard deviation. ***, p < 0.001 relative to PA14.