FIG 5.

CaSef1 and its phosphorylation are necessary for riboflavin production in the absence of iron and presence of PKA activation. (a) SC5314 cultures were grown for 8 h in the presence of ferrozine. (b) The empty vector (EV) control strain and CaTPK1 and CaTPK2 overexpression cultures were grown for 8 h. Gene expression was analyzed using qRT-PCR. Results are displayed as the average and SEM relative to the wild-type control. Statistical analysis was conducted on log₂(Y)-transformed data using one-way ANOVA with Bonferroni correction. SC5314, Casef1Δ/Δ, the CaSef1 phosphorylation mutant, and the reintegrant strain were grown for 24 h in the presence of ferrozine (c) or dbcAMP (d). The fluorescence was measured at 530 nm when excited upon 450 nm. The average and SEM of relative fluorescence to OD₆₀₀ ratios are shown. Statistical analysis was performed using a two-way ANOVA statistical test with Bonferroni correction (comparison to culture without added compound). **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.