Fig. 4

Smlt1522 plays a role in QS-related phenotypes in S. maltophilia grown in minimal media. (a,b) Growth profiles under different growth conditions. Bacterial cells were grown in LB (a) or the minimal medium MMGC (b), in microtiter plates at 30 °C and with continuous shaking. Optical density at 550 nm (OD 550 nm) was measured every 15 min for 24 h. To prepare the initial inoculum, the cells were grown overnight in the same assay medium. (c,d) Biofilm formation on polystyrene surface quantified by crystal violet staining. Cells were grown statically in a microtiter plate in LB (c) or MMCG (d) at 30 °C. Biofilm formation was normalized by cell growth and reported as relative biofilm formation. Tukey’s multiple-comparison test (one-way ANOVA) was used to determine the significance of the data between groups (ns, non-significant; **, p < 0.01; ***, p < 0.001). (e) Bacterial motility on BM2 swarming agar plates after incubation at 30 °C for four days. Swarming experiments were done in triplicate and representative images are shown. All assays include the wild-type strain S. maltophilia K279a, its isogenic mutant strain K279aΔsmlt1522 and the complemented strain carrying plasmid pBBR1-BAD-smlt1522.