The ANTHOCYANINLESS2 (ANL2) gene of Arabidopsis thaliana affects the accumulation of anthocyanin in subepidermal cells and the organization of cells in the primary root, suggesting that this homeobox gene determines the nature of epidermis and/or subepidermis. In situ hybridization showed that ANL2 mRNA accumulated in peripheral region of young leaves, flower meristems, anthers and pistils. Promoter activity of ANL2 was also examined by using uidA as a reporter. o-Glucuronidase (GUS) was expressed in the shoot apex, young leaves, root tips, anthers and ovules. In rosette leaves, subepidermal tissues showed strong GUS expression, while epidermal cells including guard cells and trichome had weak GUS expression. In the primary root, GUS was expressed in epidermal and lateral root cap cells. In the rosette leaf, the pattern of GUS expression was correlated with the pattern of anthocyanin accumulation in the subepidermis but not in epidermis. The expression of ANL2 was not affected by irradiation and the defects in TTG1.
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