Increased expression of PprB under CSS contributes primarily to the transcriptional induction of PprB-regulated genes. (A) Expression values of flp, cupE, or rcpC transcriptional reporters in the pprA mutant strain at exponential phase or after 5-h carbon deprivation. (B) Fold change values of flp, cupE, or rcpC expression upon 5-h carbon deprivation in wild-type, pprA mutant, or PApprB1 strains. (C) Expression values of pprB transcriptional reporters in the wild-type strain at exponential phase or after 5-h carbon deprivation. (D) Expression values of flp, cupE, or rcpC transcriptional reporters in the PApprB1 (PprB was constitutively overexpressed) strain at exponential phase or after 5-h carbon deprivation. All data are from three independent experiments and shown as the means ± SDs. Statistical analysis was based on pairwise strain comparisons (t test). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant.