Varietals

A team of scientists led by Laurent Deluc and colleagues from the University of Nevada, Reno and Boston University School of Medicine, has uncovered new information that's set to transform our understanding of the grape ripening process. Deluc's team surveyed 7 different stages of grape berry development for the V. vinifera Cabernet Sauvignon variety of grape. The scientists analyzed the role of RNA in a host of processes including organic and amino acid metabolism, photosynthesis, circadian cycles and pathogen resistance. In particular, genetic changes associated with calcium signaling genes that play a role in aroma and flavonoid compound production were mapped. And analysis of sugar metabolism gene expression pattern revealed a previously uncharacterized pathway for glucose and triose phosphate production invoked from véraison to mature berries. It's hard to predict how these discoveries will affect wine production in the short-term as functional testing is required, says Deluc. "But, for sure, it may help by providing new elements to enhance our understanding of berry development. That could help growers estimate the best day to harvest their grapes and hence produce better wines," says Deluc. For example, it might be possible to improve the aging of certain wines by altering the genetic expression of certain tannins—which play a key role in stabilizing wine over time. Deluc is currently working on a separate paper about the effect of water deficit on wine quality that identifies specific genes that could be used as bio-markers of the grapevine and also of wine quality. "In the near future we might be able to overexpress one of these genes to improve grapevine tolerance to stresses such as cold, salt or water. By identifying those genes related to these abiotic stresses, we will be able to choose exactly the right clone to grow—even in the desert or mountainous regions," says Deluc. More Online Exclusive articles: