Figure 4.

Regulatory effects of transcription factors on the promoter activities of CitSUS5 and CitSWEET6. Schematic map of the CitSUS5-LUC construct A) and CitSWEET6-LUC construct B). The ratio of firefly luciferase (LUC) and Renilla luciferase (REN) of the empty vector (SK) plus promoter was set at 1. Error bars represent SE based on 4 biological replicates. Asterisks denote significant differences using Student's t-test (*P < 0.05; **P < 0.01). In C and D), yeast one-hybrid analyses. Autoactivation of proSUS5-pAbAi and proSWEET6-pAbAi was tested on SD/-Ura in the presence of 300 and 150 ng mL⁻¹ aureobasidin A (AbA), respectively. Physical interaction was determined on SD medium lacking Leu in the presence of the corresponding amount of AbA. The empty pGADT7 vector was used as negative controls. E and F) In vitro binding of CitNAC47 to the promoter of CitSUS5 and binding of CitZAT5 to CitSWEET6 performed by electrophoretic mobility shift assay (EMSA). Wild-type probes containing the recognition motives (Supplemental Table S3) were biotin labeled, while competition for binding was performed with unlabeled probes and mutant probes. The symbol + or − represents presence or absence, respectively; +++ indicates increasing amounts.