Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12866-016-0849-6/MediaObjects/12866_2016_849_Fig1_HTML.gif)
Sensitivity of the wild-type and mutant strains to NaCl and alkaline. Wild-type (WT), ΔprkA (prkA deletion mutant), and CΔprkA (complement of ΔprkA) bacterial cells were grown to OD600 ≈ 0.8 in TY broth medium, adjusted to OD600 ≈ 0.2, and then serially diluted and spotted onto TY agar plates containing no additional NaCl or 0.4 M NaCl at neutral pH, and TY agar plates at alkaline pH (pH 9). Ten-fold serial dilutions are shown. The plates with no additional NaCl were incubated at 28 °C for 3 days, while the plates with 0.4 M NaCl and the plates at pH 9 were incubated for 5 days at the same temperature