Muscadine, Resveratrol (RSV) Synthesis, and the Nutritional Benefits to Humans and Plants

Vitis rotundifolia, commonly known as the muscadine, is a native grape of the southeastern United States. Muscadine is highly pest resistant and drought tolerant. These properties have been attributed to the much more robust production of a phytoalexin called resveratrol (RSV)a secondary metabolite known for its cellularly protective properties. Primarily, RSV functions as a scavenger of free radicals but is also known to be a stimulator in the synthesis of other antioxidants such as glutathione (GSH). RSV synthesis is known to be modulated by the actions of stilbene synthase (STS) with a host of STS genes being identified as possible regulators of its production. In plants, RSV boosts immune responses to stress, growth, injury, and disease. Similarly, in humans, RSV exerts both antimicrobial and anti-inflammatory activities. It is known to protect cells in metabolic disease states such as diabetes and is shown to inhibit neural degradation in Alzheimer’s disease. Since muscadine grapevines cannot naturally hybridize with common wine grapes of Vitis vinifera, the RSV benefits cannot be readily introgressed into the existing cultivars. Thus, muscadine is a promising target for molecular breeding to increase the synthesis of RSV in plants with the ultimate goal of improving human health. This paper explores the biology of muscadine grapes, provides a broad background on the biochemistry and regulation of RSV synthesis, and highlights the STS genes in muscadine as a promising genetic tool to manipulate RSV production in plants.