Characterization of cucumber violaxanthin de-epoxidase gene promoter in Arabidopsis.

Violaxanthin de-epoxidase (VDE) activates the dissipation of excessive light energy as heat and protects the photosynthetic apparatus from photo-damage. Here we quantitatively analyzed the expression characteristics of cucumber violaxanthin de-epoxidase (CsVDE) promoter using the 1983 bp upstream fragment, and a series of 5'-truncated fragments, to drive β-glucuronidase (GUS) expression in Arabidopsis. The activity of CsVDE promoter was altered by hormones and abiotic stresses are positively by indole-3-acetic acid and gibberellin, but negatively by polyethylene glycol, abscisic acid, salicylic acid, mannitol and sodium chloride. Quantitative analysis by fluorometry of GUS activity and histochemical localization showed that the CsVDE promoter is green tissue-specific. A 334 bp fragment was sufficient to drive the expression of GUS to the same extent as the longest 1983 bp one in green tissue-specific manner. Further analysis of the promoter led to the discovery of one enhancer region and two silencer regions. The activities of GUS driven by the CsVDE promoter fragments were increased when plants were exposed to high light for 4 h, but decreased by 8 h illumination. The high light responsive elements were defined in two positions. The normal-level light-responsive elements were also found in different regions.