Grapes' Color Linked to a Gene's Inner Workings

Agricultural Research Service (ARS) scientists have made an importantgenetic discovery that, in addition to unlocking secrets about why grapes aredifferent colors, may allow for more efficient breeding of color-specificgrapes.

Color is perhaps the most important of grape characteristics, a criticalcomponent of table, juice and wine grapes that's also been linked toantioxidant content.

Plant geneticistChristopherOwens of ARS' newGrapeGenetics Research Unit in Geneva, N.Y., and collaborators at France'sNational Institute of Agricultural Researchin Montpellier found that much of the color variety in modern grape cultivarscan be traced to variations in a gene recently found to be a causative factorin white grapes' lack of color.

The variations in this gene, which is called VvmybA1, are caused, inpart, by movement of Gret1, a genetic mutation within it, according toOwens.

He explained that Gret1 is a type of element that's also known as atype of "jumping gene" because it's a piece of DNA that moves aroundwithin a genome. Owens found that Gret1's movements slightly alter thesurrounding DNA. These alterations create additional variations inVvmybA1, which in turn influence the grape's fruit color.

The finding is a potential milestone in grape research and production thatmay one day lead to breeding for color-specific grapes as well as for grapesthat can enhance the stability of wines and juice, according to Owens. It mayalso spur better understanding of relationships between fruit color andhealth-imparting compounds, as well as the effects of environment andmanagement practices on grape color and quality.

The research may even lead to the development of grapes with novel colors.

Owens' work expanded on independent 2004 research in Japan that identifiedGret1 and showed that its interaction with VvmybA1, which isfound in all Vitis vinifera grapes, causes white grapes' color.

Readmore about this research in the April 2006 issue of AgriculturalResearch magazine.

ARS is the U.S. Department ofAgriculture's chief scientific research agency.