Genetic Transformation for Overexpression of Flavonoid Compounds in Muscadinia Grape Cell Cultures
Among the unique changes that take place during grape berry development, those affecting the flavonoid pathway have triggered a number of investigations for over a decade. Anthocyanins, which are expressed in red and black grape cultivars and responsible for the color of red wine, are biosynthesized via the flavonoid biosynthetic pathway. The MYB gene is known to encode a transcription factor that induces the anthocyanin biosynthesis in grapes. In this article, we describe the transformation of the somatic embryos of ‘Supreme’ and ‘Darlene’ varieties of muscadine, with targeted constitutive ectopic expression of MYBgene in grape somatic embryogenic callus. The ectopic expression of MYBtriggered de novo production and storage of anthocyanins in all transgenic cells including the hypocotyl, leading to a very intense red coloration. The ectopic red pigments were as a result of the accumulation of anthocyanins in the tissue. Molecular analysis using gene specific primers confirmed the proper integration and overexpression of the MYB gene. Our results strongly support the previous studies that MYBgenes are involved in the regulation of anthocyanin biosynthesis in the grape via expression of the UFGT gene.