Fig 2: Contribution of the TCS PhoPQ and the master stress regulator RpoS to the environmental survival of K. pneumoniae. Ex vivo solid surface survival of KPPR1S and its isogenic mutants. (A) The impact of loss-of-function mutations in MgrB−, RpoS−, and the double mutant MgrB−, RpoS− on K. pneumoniae survival. (B) The contribution of the sensor kinase PhoQ in the environmental survival of K. pneumoniae. (C) MgrB−-dependent enhanced survival is dependent upon both RpoS and PhoQ. The WT and MgrB− data are repeated in each panel. Shown is the mean and SEM of six independent assays (in duplicate). Statistical differences were calculated using Kruskal-Wallis tests with Dunn’s test of multiple comparisons across strains at each time point. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; n.s., not significant.

Fig 3: Functional Linkages between the Ribosome Head Domain Protein Factors RelA, RelE, and AdhE Regulate Gene Expression and Phenotype(A) RNA-seq analysis of Keio parent strain (BW25113) or isogenic strains lacking relA, relE, or adhE genes. The compared strains are identical except for the ten nucleotide variants encoded by the pKK3535-BBB and pKK3535-HBB rDNA plasmids. All experiments were performed on isolated polysome fractions in biological triplicate.(B)Gene ontology enrichment analysis of differentially expressed genes from (A).(C) Quantification of RpoS protein levels measured by western blot and normalized to total protein (n = 5). Representative blot and loading control of total protein visualized by the Colloidal Blue Staining Kit are shown.(D–I) The impacts of ribosome sequence variation on (D–G) cell motility and (H and I) biofilm formation. Genetic backgrounds are listed on the x axis. Error bars indicate SEM. *** indicates p < 0.01.