The common muscadine grape is native to the southeastern United States and has been cultivated for more than 400 years. The discovery of high concentrations of antioxidant compounds in berry, juice, and wine has brought increased attention to muscadine grape, not only as an important alternative cash value crop for the southeastern United States, but as new healthy food as well (Colova et al., 2007). Muscadine grapes are considered one of the most important Vitis species because of their containment of several unique flavonoid compounds that have beneficial nutraceutical properties. They are the only grapes containing ellagic acid in the skin, and possess one of the largest antioxidant levels among fruits (Samuelian et al., 2009).
Most grapevine cultivars can be divided into two groups, red and white which is based on the expression of anthocyanin in the berry skin (Walker et al., 2007). The berry color locus comprises two very similar genes, VvMYBA1 and VvMYBA2 and either gene can regulate color in the grape berry (Walker et al., 2007). Therefore, MYB related transcription factor genes such as VvMYB can regulate anthocyanin biosynthesis (Kobayashi et al.
, 2002). Anthocyanins are red or purple colored secondary metabolites that are present in the leaves, stems, flowers and fruits of many plants. Their accumulation is mostly responsible for pigmentation in red and black grapes which is essential in wine making and they are localized in the berry skin. Genes that readily affect stages in the biosynthesis of anthocyanin’s often result in colorless phenotypes, however if a mutation exist later in the pathway it may only affect the type of anthocyanins produced (Martinelli and Girbaudo, 2001).Antioxidants are produced in most bright colored fruits, and researched as possible preventative of diseases, such as Alzheimer’s and cancer. Research suggests that antioxidants can indeed be effective in preventing a number of age related diseases. They fight oxidative stress and free radicals (Bogs et al.
, 2007). Cell suspension cultures can synthesize high levels of anthocyanins, proanthocyanins, and other flavonoids. The products accumulate in plant cell cultures parallel to those produced in vivo in the plant, and mixtures of co-occurring phytochemicals can be more easily harvested from the cultures (Youself et al., 2004). Cultivars of color accumulate anthocyanin in their skins, whereas white skin cultivars do not. MYB related factors genes such as vVMYB regulate anthocyanin biosynthesis (Kobavashi et al, 2002). This approach has allowed us to access the nutraceutical value of commercial North American grape varieties, and to contribute knowledge about genomic mechanism affecting the production of flavonoid compounds in grapes. In addition, the technology could enhance the use of genomic sequences to improve nutritional and health benefits of the American native grapes.
Muscadine grapes are not only a cash crop for the Southeast United States, but also a healthy food. Muscadines have a very high concentration of antioxidants. Antioxidants are being studied as a potential cure for cancer, Alzheimer’s, and cardiovascular disease. They can help reduce free radicals, which is the onset for cancer, and plays a major role in the aging process. The antioxidants are known to be in grapes where the red coloring is produced. Anthocyanins are the main color pigments in plants.
The red color is triggered by the release of anthocyanins. To determine the biosynthetic process for anthocyanin production, we had to obtain the cDNA’s encoding the MYB gene. The MYB gene is a transcription factor that turns on and off the production of anthocyanins. Our intention is to increase the production of anthocyanins by cloning and overexpressing the MYB gene in cell culture, which will lead to the overexpression of the red coloring. It can be assumed that by increasing the expression of anthocyanins in cell lines, the production of antioxidants will also be increased. The MYB gene has never been cloned from muscadine grape.
Being able to clone the MYB gene in such a prominent plant species of fruit may lead to new discoveries in research. The health benefits within this fruit are not only in the berry itself, but can also carry through the wine production. Cloning the MYB gene will not only improve the economic value of muscadines, but the information obtained in this research will also, be used to elucidate other plant species that produce anthocyanin. The results will also be available in the national database, for the use of more research using different species.