FIG 4.
Effect of extracellular potassium on rsmB expression and growth in P. wasabiae. (A) The expression of the rsmB promoter fusion (PrsmB::gfp) was measured by flow cytometry of cultures of WT bacteria and trkA::Tn5, trkH::Tn5, gacA, gacA trkA::Tn5 mutants grown to an OD600 of 0.3 in minimal potassium medium supplemented with a final potassium concentration of 0.25 mM, 2.5 mM, 25 mM, or 250 mM. NG, no growth. Error bars represent SEM; n = 6. (B to E) The OD600 was measured throughout growth for WT bacteria and trkH::Tn5 and trkA::Tn5 mutants in minimal potassium medium supplemented with 0.25, 2.5, 25, or 250 mM KCl (for growth rates, see Table S4 in the supplemental material).