Grape Genomics

"Wine," said Robert Louis Stevenson,"is bottled poetry." For centuries winemaking has been something of a romantic pursuit, more art than science. Grape growers, or viticulturists, have experimented with the complex interplay of sun, soil and water, but they knew very little about what was actually happening inside the grapes.

For example, growers have long known that by clipping leaves, thinning out bunches on the vine or creating drought conditions, they can obtain smaller grape berries with more concentrated flavours. But so far science has not been able to explain why these practices work.

That may be about to change, thanks to a joint project of Genome Canada and Spain’s Genoma España. The aim is to apply genomics in order to decipher some of the ancient mysteries of wine grape cultivation.

Leading the project is Dr. Steven Lund of the University of British Columbia (UBC), in collaboration with Dr. Jörg Bohlmann (also of UBC) and Dr. José Martinez Zapater of the Universidad Autónoma de Madrid. "The vintage is affected by the environment, both natural and human-made," explains Dr. Lund, "and the genetic makeup of the grape berry is responding to fluctuations in the environment throughout each season." By sequencing the genes of the grape berry, researchers hope to discover more about that response, and particularly its impact on the time of ripening and the quality of grapes.

As the grapes continue ripening on the vine, sugars accumulate, acid levels decline, flavour and aroma compounds are synthesized, and red grapes acquire their pigment. The balance of these factors determines the overall quality of the grapes and the wine eventually made from them. The grower must decide when the balance is exactly right and the time has come to harvest the grapes.

The problem for viticulturists is that there are no signals that the transformation is about to occur. What causes the changes? Why do some grapes ripen faster than others? What are the biological effects of sun and shade? What’s really going on at the molecular level?

Lund hopes that with an understanding of the genetic blueprint, viticulturists will be better able to detect, direct and monitor the onset of ripening even before it can be seen in the grapes themselves. This could translate into a major advantage: growers could synchronize earlier maturation and potentially produce more consistent, excellent wines.

To provide the necessary information, Lund sees one offshoot of the research project being the development of hand-held tools that growers could carry into the vineyard to detect the presence of key proteins.

The wine grape is the most economically important fruit on the planet, with more than 7.4 million hectares planted in vineyards worldwide. Viticulture is also a fast-growing sector of the Canadian economy, particularly in British Columbia. Sales there of wines bearing the mark "VQA" – that is, certified by the Vintners Quality Alliance – rose from about $7 million in 1991–92 to over $130 million in 2005–06.

According to Dan Paszkowski, President of the Canadian Vintners Association, this research "will bring significant benefits to the industry by allowing our members to get the most out of their grapes regardless of the conditions they face. It really takes us from the known to a whole new level."

While science may be removing some of the poetry and romance from winemaking, it presents the possibility of supporting the production of more consistent, world-class wines in Canada. That’s something even Robert Louis Stevenson would be likely to applaud.