European scientists decode wine grape genome, find flavor genes

By Marlowe Hood, PARIS, AFP

Scientists in France and Italy have deciphered the complete genetic code for the plant producing wine grapes, according to a study published Sunday.

While the findings will do nothing to enhance the mystique of winemaking, they could pave the way for gene based manipulations to boost flavor and improve resistance against disease.

Dozens of researchers analyzing the Pinot Noir varietal of Vitis vinifera, the core species from which virtually all grape wine is made, found twice as many genes contributing to aroma than in other sequenced plants, suggesting that wine flavors could be traced to the genome level.

The French-Italian Public Consortium for Grapevine Genome Characterisation, which collectively authored the study, also gained crucial insights into the genetic evolution of plants over the last 200 million of years.

V. vinifera is only the fourth complete genetic sequence ever produced for a flowering plant, and the first for a fruit crop.

The other three are rice, the poplar, and Thale Cress, a species of wild plant related to mustard and cabbage.

Pinot Noir, the signature grape of the famous Burgundy wine region in northern France, was selected because of its inbred genotype, which made it easier to sequence.

The study, published in the British journal Nature, will be of enormous interest to global grape growing and wine industries eager to diminish costly plant disease and enhance the flavor of a product that generates some US$200 billion (150 billion euros) a year in revenue.

“It is strategic for a species as economically important as the grape vine to develop the tools and genetic resources” to resist pathogens and improve quality, wrote Anne-Francoise Adam-Blondon, one of the authors, in explaining the origin of the Franco-Italian initiative.

The researchers discovered that V. vinifera had large “families” of genes “directly correlated with the aromatic features of wine,” especially related to tannins and terpenes.

Tannins, astringent compounds found in the grape skin and seeds — especially red grapes — adds body and structure needed for aging, and are considered essential for producing a balanced wine. They are also thought to help prevent hardening of the arteries.

Terpenes are the main ingredient in the essential oils of many plants and flowers widely used as natural flavor additives for food, and in fragrances. In wines, they are especially concentrated in the Muscat grape, where they exude floral tones of rose and violet.

The study also identified the genetic source in the plant of resveratrol, the anti-oxidant in red wine that been widely associated with health benefits ranging from anti-aging to boosting anti-viral treatments.

Perhaps even more important to winemakers than manipulating molecules related to taste — which is sure to generate controversy — is the potential to make V. vinifera more resistant to diseases that causes tens of millions of dollars in damage every year.

Research is already underway, noted Adam-Blondon, to isolate a gene that could increase resistance to oidium, an common form of mildew to which Pinot Noir is especially vulnerable.

This would also help reduce the use of chemicals in grape growing, she added, pointing out that in France that grape vines account for three percent of farm land cultivated, but 20 percent of herbicides used.