Light-dependent regulation of FdTSPO transcript levels under diurnal cycles. Samples for quantitative real-time reverse transcription PCR (qRT-PCR) were taken from white light (WL; ∼10 µ mol−2 s−1) grown wild-type Fremyella diplosiphon cells acclimated to a 12 h diurnal cycle at 12 h into the light (L12) or dark period (D12) and 3 h into the light period (L3) [see schematic in (A)]. (B) qRT-PCR analysis for FdTSPO genes, including primers used, was as described in Busch et al, 20164. The relative expression level compared with ORF10B gene is shown as average values ( ± SD, n = 3). Expression of each FdTSPO is shown relative to expression levels at L12 sampling time. Identical letters over bars represent homogenous mean groups (p > 0.05), whereas asterisks indicate a significant difference (*p < 0.01, **p < 0.05) between expression level at 0 h relative to each time point, as determined by ANOVA and Tukey test.