DEWAX-mediated transcriptional repression of cuticular wax biosynthesis in Arabidopsis thaliana

摘要

he aerial parts of plants are covered with a cuticular wax layer, which is the first barrier between a plant and its environment. Although cuticular wax deposition increases more in the light than in the dark, little is known about the molecular mechanisms underlying the regulation of cuticular wax bio-synthesis. Recently DEWA X (Decrease Wa x Biosynthesis) encoding an AP2/ERF transcription factor was found to be preferentially expressed in the epi-dermis and induced by darkness. Wax analysis of thedewax knockout mutant, wild type, and DEWA X overexpression lines (OX) indicates that DEWAX is a negative regulator of cuticular wax biosynthesis. DEWAX represses the expression of wax biosynthetic genes CER1, L ACS2, ACL A2, and ECRvia direct interaction with their promoters. Cuticular wax biosynthesis is negatively regulated twice a day by the expres-sion of DEWA X; throughout the night and another for stomata closing. Taken together, it is evident that DEWAX-mediated negative regulation of the wax biosynthetic genes plays role in deter-mining the total wax loads produced in Arabidopsis during daily dark and light cycles. In addition, significantly higher levels of DEWA X transcripts in leaves than stems suggest that DEWAX-medi-ated transcriptional repression might be involved in the organ-specific regulation of total wax amounts on plant surfaces.