BIS1 transactivates iridoid genes in transient assays. (A) Transactivation in transfected N. tabacum protoplasts of iridoid and MIA promoters driving firefly luciferase (fLUC) expression by effector plasmids expressing BIS1, ORCA3, or MYC2. Values in the y axis are normalized fold-changes relative to protoplasts cotransfected with the reporter constructs and a pCaMV35S:GUS (GUS) control plasmid. For the normalization procedure, see SI Appendix, SI Materials and Methods. The error bars designate SE of the mean (n = 8). (B) Transactivation in agroinfiltrated N. benthamiana leaves of pG8O and pSTR1 driving fLUC expression by effector plasmids expressing BIS1, ORCA3, and MYC2. Values are normalized fold-changes relative to leaves coinfiltrated with the reporter constructs and a pCaMV35S:GFP (GFP) control plasmid. The error bars designate SE of the mean (n = 8). (C) Transactivation in bombarded C. roseus MP183L cells of pG8O driving GUS expression by effector plasmids expressing BIS1 and MYC2. Values are fold-changes relative to cells cobombarded with the reporter construct and a pCaMV35S:GFP (GFP) control plasmid. The error bars designate SE of the mean (n = 3). In all cases, statistical significance was determined by the Student’s t test (*P < 0.05, **P < 0.005, ***P < 0.0005).