Fig. 4

β-galactosidase activities of Category I-V predicted SigB promoters that were translationally fused to lacZ upon exposure to heat, ethanol, and salt stress. β-galactosidase activities of Category I-V predicted SigB promoters that were translationally fused to lacZ were investigated upon exposure to heat (37 °C > 48 °C), 4% (v/v) ethanol, and 6% (v/v) NaCl in wt cells and in the ΔsigB mutant of B. subtilis. Each data point represents a biologically independent replicate, and the bar indicates the average value for the three independent experiments. β-Galactosidase (LacZ) activities are presented in Miller units per milligram protein. The color-coded box at the right of each graph indicates the different categories to which the promoters belonged, based on the confidence level of the predicted PBM. Category I (green): the predicted PBM has the exact match at both − 35 and − 10 regions. Category II (orange): the predicted PBM has either an exact match at the − 35 region, with 1–2 bp variations at − 10, or vice versa. Category III (yellow): the predicted PBM has conserved GTTT bases at the − 35 region and the GG bases at the − 10 region. Category IV (grey): low-level homology compared with the conserved motif with borderline p-values; and Category V (Blue): with a duplicated − 35 or − 10 region. A P_rsbV-lacZ activities; B P_ytoQ -lacZ activities; C P_pucI -lacZ activities; D P_ylaL-lacZ activities; E P_ygaO-lacZ activities; F P_ykaA-lacZ activities. G P_ywzA-lacZ activities; H P_yaaI -lacZ activities; I P_gtaB -lacZ activities