FIGURE 2.

Time-course luminescence induction curves of B. thailandensis E264 clones containing the B. thailandensis fluoride riboswitch and repression effect. A 54 h time-course lux expression assay comparing lux/OD (A) and growth curves (B) of B. thailandensis E264 containing the P1-B. thai F RS-lux (pVK-f2-lux) constructs (See Supplementary Table S3: B. thailandensis E264/P1 + B. thai F) for either an ON-induced state of the fluoride riboswitch in the presence of 31 mM F⁻, or an OFF-repressed state fluoride riboswitch in the absence of F⁻. Cultures were grown and measured on the same 96-well microplate assay run and maximum peak levels of luciferase expression are indicated above curves in Relative Luminescence units (RLU) for un-normalised-to-OD signal strength comparison. The data points represent the means and standard deviations of triplicate values. (C) In vivo repression capability of three OFF-repressed riboswitch-containing constructs in B. thailandensis E264: B. thailandensis fluoride riboswitch construct (pVK-f2-lux—B. thai F RS), the P. syringae fluoride riboswitch (pVK-f-lux—P. syr F RS), and the B. thailandensis metX 5′UTR (B. thai metX 5′UTR). OFF-repression was achieved with 0 mM F- for fluoride riboswitch constructs and with 0.05 mM methionine for the metX 5′UTR construct which is suspected to have a regulatory element (Leyn et al., 2014; and unpublished data). RLU per OD₆₀₀ and growth curves are shown as well (bottom left and right respectively). The data points represent the means of triplicate values.