Significance of the Expression of the CER6 Condensing Enzyme for Cuticular Wax Production in Arabidopsis

• Published in: Plant physiology (Bethesda) 2002-08, Vol.129 (4), p.1568-1580
• Main Authors: Hooker, Tanya S., Millar, Anthony A., Kunst, Ljerka
• Format: Article
• Language: English
• Subjects: Accumulation; Acyltransferases - genetics; Arabidopsis - drug effects; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins; Base Sequence; Biochemical Processes and Macromolecular Structures; Biological and medical sciences; Cell biochemistry; Cell physiology; Environmental factors; Enzymes; Epidermis; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Genes; Green Fluorescent Proteins; In Situ Hybridization; Light; Lipids; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; Messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Nicotiana - genetics; Plant Epidermis - metabolism; Plant physiology and development; Plants; Plants, Genetically Modified; Promoter Regions, Genetic - genetics; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; RNA; Seedlings; Stems; Substrate Specificity; Time Factors; Transcription. Transcription factor. Splicing. Rna processing; Transcriptional Activation - drug effects; Transgenic plants; Water - pharmacology; Water deficit; Waxes; Waxes - metabolism
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.003707

To learn more about the role of the CER6 condensing enzyme in Arabidopsis surface wax production, we determined CER6 transcription domains and the timing of CER6 transcription in vegetative and reproductive structures from juvenile, mature, and senescing tissues. We found that CER6 is highly transcribed throughout development, exclusively in the epidermal cells in all tissues examined. The only exception to the epidermal expression was observed in anthers nearing maturity, in which CER6 mRNA was localized in the tapetum. To determine if environmental factors such as light and water deficit, which are known to stimulate wax accumulation, induce CER6 transcription, we examined the effects of these factors on CER6 transcript abundance. Our results demonstrate that light is essential for CER6 transcription, and that osmotic stress and the presence of abscisic acid enhance CER6 transcript accumulation. CER6 promoter-directed expression of the β-glucuronidase reporter gene in transgenic plants demonstrated that the CER6 promoter was highly effective in directing epidermis-specific expression in Arabidopsis and tobacco (Nicotiana tabacum). Furthermore, CER6 promoter-driven CER6 overexpression resulted in increased wax deposition in Arabidopsis stems. These experiments indicate that the expression level of CER6 in the epidermis is one of the factors controlling wax accumulation on Arabidopsis stems.