Cloning of the chrysanthemum UEP1 promoter and comparative expression in florets and leaves of Dendranthema grandiflora.

To attain high transgene expression in petal tissue of ray florets of chrysanthemum an endogenous ubiquitin extension protein (UEP1) promoter was cloned and tested with the beta-glucuronidase (GUS) reporter gene. Expression levels were compared with four heterologous promoters: chalcone synthase (chs-A) and zinc finger transcription factor (EPF2-5) from petunia, eceriferum (CER6) from Arabidopsis and multicystatin (PMC) from potato. The comparison of the expression levels of the different constructs in ray florets, disc florets, and leaves is presented. The highest mean expression in petal tissue of ray and disc florets was conferred by the UEP1 promoter, followed by CER6 and EPF2-5. The UEP1 promoter in ray florets confers over 50-fold enhancement in expression as compared to CaMV 35S-based promoters.