One of the most popular episodes of the 8000 year history of grape cultivation led to biological changes that are not well understood – until now. Through biomolecular research work, German researchers have discovered new details about the legacy of Vitis varieties in cultivation today. In the process, which has opened the way for more meaningful classification, accelerated playback, and a more accurate assessment of the results, which would break a bottleneck in the progress of the wine industry.
Their discovery removes a major barrier to development already underway – that is, a shift to the raising of the vine guided by highly specific genetic markers. You can even point the way to European production and tasting of wines from the North American cultivars, moisture-free “or” foxy “flavors associated with the vine in the New World.
In response to the plague of “great European wine” from the mid 1800s, producers to preserve the most desirable qualities of European grapes, while the resistance breeding of varieties of North America. These were naturally resistant to pests native found his way – in steamships, most likely – across the Atlantic to Europe. Starting around 1860, the introduction of two pests of North America – an aphid and a fungus – almost destroyed the wine industry, especially in France. A century ago, many hybrids were in use, but the wine they produced was regarded as inferior in flavor that producers were prohibited from mixing with traditional higher quality wines.
Today, farmers and producers have many reasons for wanting to know the heritage of the vine, and easily see the features is rarely sufficient. To distinguish between the many varieties of grapes, not even the experts need more than it seems. Much of the history of a plant can be read at the molecular level, based on their DNA and biochemistry, and modern scientific tools have been developed to discern the “fingerprints” of the Old World, New World and hybrid vines. The new research shows, however, that one of the best tools for fingerprinting set is not totally reliable, since genetics is a simple story of biomolecular data records.
The research was a collaboration between the Technische Universitaet Muenchen, Bavaria and the Institute for Grapevine Breeding jki, along the Weinstrasse famous or “wine route” in the Palatinate region. The clues led researchers to suspect that a difference in a particular marker phytochemicals that has been used to distinguish grape varieties is due to a unique genetic mutation, but a double mutation. Also revealed, the chromosome carrying the double mutant gene is one that can also carry a gene responsible for the poor, “musty” smell of the North American varieties. A complex series of experiments and analysis confirms, and rule out other possible explanations. A detailed description of the methods and results are published in the Journal of Agricultural and Food Chemistry.
The biochemical process in the crux of the research is the production of anthocyanin pigments. European Network of Vitis vinifera cultivars produce only compound pigments, such as malvidin called oenin (3-O-glucoside), while most other Vitis species and hybrids can produce compounds such as pigments Malvin (malvidin 3,5-di -O-glucoside) as well. This subtle difference that has been used to classify varietal wines by origin, had been attributed to a particular genetic mutation, inherited by European plants. If that was the whole story, however, some breeding programs might have been expected to turn in the production of Malvin in European varieties, and this has never been observed.
Wilfried Schwab Professor of Biomolecular Food Technology TUM Department led the effort to find out what genetic changes would restore enzyme activity malvin producers in the European varieties – with the main objective of the mocking of the lack of details of his family history. The researchers carried tools includes techniques to isolate and reproduce DNA sequences of interest, rewriting specific parts of the genetic code – through what is called site-directed mutagenesis – and determine the three dimensional structure of proteins expressed as a result. His discovery of a double mutation could lead to development of classification tools more accurate and efficient marker assisted breeding methods. They suggest that this knowledge could also be used otherwise, so that American and European species to produce varieties of wine tasting, free of moisture “or” foxy “flavors associated with New World varieties.
More information: “A Double Mutation in the Anthocyanin 5-O-Glucosyltransferase Gene Disrupts Enzymatic Activity in Vitis vinifera L.” by Laszlo Janvary, Thomas Hoffmann, Judith Pfeiffer, Ludiger Hausmann, Reinhard Toepfer, Thilo C. Fischer, and Wilfried Schwab. Journal of Agricultural and Food Chemistry, 2009, 57, 3512-3518 (DOI:10.1021/jf900146a).
Source: Technische Universitaet Muenchen – Sponsored by Beer Opener.