Fig. 3.

A cyclic diadenylate monophosphate (c-di-AMP) riboswitch transcriptionally regulates the kdp operon. a Scheme of plasmids pBC0 and pBC2 carrying a lacZ gene fused with the kdp operon promoter or the promoter with a c-di-AMP riboswitch, respectively. b The β-galactosidase activities for BMB171 carrying plasmids with (pBC2) and without the c-di-AMP riboswitch encoding region (pBC0) at different K⁺ concentrations. Data are expressed as box-and-whisker plots, where the central lines denote medians, edges represent upper and lower quartiles and whiskers show the minimum and maximum values. Data were subjected to one-way analysis of variance (ANOVA) using the Bonferroni test, n = 3; p values are shown above each panel. c Relative expression levels of kdpA, kdpB, and kdpC genes in the BMB171 and the ΔUTR strains measured by real-time quantitative PCR (RT-qPCR), respectively. Data are expressed as box-and-whisker plots, where the central lines denote medians, edges represent upper and lower quartiles, and whiskers show the minimum and maximum values. Data were subjected to one-way analysis of variance (ANOVA) using the Bonferroni test, n = 3; p values are shown above each panel. Data underlying the plots in b, c are available in Supplementary Data 5