Wound-responsive cis-Element in the 5′-Upstream Region of Cucumber Ascorbate Oxidase Gene

Abstract

  The cucumber (Cucumis sativas) AAO1 gene (former name, Aso1) encodes an ascorbate oxidase that catalyzes the oxidation by molecular oxygen of ascorbic acid to dehydroascorbate. CsAAO1 mRNA concentrations rose rapidly after mechanical wounding of cucumbers. To study the wound-responsive expression of CsAAO1 in detail, we examined transgenic tobacco plants harboring a CsAAO1 promoter-β-glucuronidase fusion gene. CsAAO1 promoter activity in leaves of the tobacco was induced by wounding. Analysis of the regulatory properties of 5′-deleted promoter fragments showed that a putative wound-responsive cis-element (WRE) was located −736 to −707 bp from the translation initiation site. DNA binding factors that bound specifically to the putative WRE sequence were identified in tobacco nuclear extracts by gel retardation assays.