Issue link: http://winesandvines.uberflip.com/i/66137
WINEMAKING The technique proved very useful for determining, for ex- Highlights • Technologies for rapid genetic sequencing—collectively known as PCR—are developing rapidly and plummeting in cost. • Advanced PCR techniques are making headlines in many fields, from profiling the microbes in human digestion to studying disease patterns. • Cutting-edge PCR has great potential for deepening our under- standing of grapes and wine—if funding can be secured. event held at the University of California, Davis, in March. David Mills from the Department of Viticulture & Enology and Johan Leveau from the Department of Plant Pathology did a dual pre- sentation about the advantages of the new technology, including some tantalizing snippets of initial research. Mills was an early adopter of PCR—polymerase chain reaction, a method of finding and replicating tiny fragments of DNA for anal- ysis—in the field of wine studies. A decade ago, he began using a technique known as quantitative PCR to get definitive answers about how much of a particular life form is present in a sample of wine or juice. With quantitative PCR, a target is established—the DNA tem- plate for the thing you are looking for—and then the machinery goes out and finds it and counts it in the sample. ScottLabs_Aug10.qxp 6/29/10 3:58 PM Page 1 ample, how much Brettanomyces was in a wine and led to the development of assays for yeast strains, acetic acid bacteria and so on. PCR at this level already had significant advan- tages over traditional plating and culturing. Some things sim- ply do not thrive on plates, and even those that do mean the researcher is looking at a population once removed from the original sample. Perhaps the main limitation of quantitative PCR is that wine—and most of the really interesting things in life—is much more complex, full of dozens and hundreds of microbes in a dynamic ecosystem, including things no researcher knows to look for. Johan Leveau tried PCR on the surface of grapevine leaves and grape berries and discovered organisms not found in any current DNA database. Using what Mills and Leveau called comprehensive PCR, it's possible to ask the machinery—in this case, a Roche 454 se- quencing system—to check out and report back on everything in the sample, all the DNA of all the critters, not only the slam- dunk usual suspects but any novel microbes that might be on the scene. 2 Barrel Washers • 4 Barrel Washers Barrel Processing Lines • 1/2 Ton Bin Washing Systems 35 lb. Picking Lug Washers • Custom Cellar Equipment Tom Beard Company 1650 Almar Parkway, Santa Rosa, CA 95403 P. 707-573-3150 www.tombeard.com F. 707-573-3140 E. jmendoza@tombeard.com Wines & Vines JULY 2011 51