The vast majority of wine does not involve genetically modified organisms (GMOs). Let me repeat, the vast majority of wine does not involve GMOs. On to the rest of the story:
Whether wine contains genetically modified organisms (GMOs) is a question I’m asked often. In general, the answer is no. Genetically modified grapevines aren’t being used for commercial winemaking (though not for want of trying). Two genetically modified wine yeasts have crossed the commercial production threshold, but not worldwide. One, the un-charismatically named ECMo01, available only in the United States and Canada, has been engineered to produce an enzyme that degrades urea. That’s a useful property because urea in wine can become ethyl carbamate, which the World Health Organization thinks is probably carcinogenic enough to be worried about it.
The other, ML01 (which rolls off the tongue much more easily), is legal in the US and Canada as well as Moldova, and seems to have won more traction (though not, I dare say, because it’s available in Moldova). ML01 includes genes for two non-Saccharomyces cerevisiae proteins: a malate permease from fellow yeast Schizosaccharomyces pombe, and a malolactic gene from the lactic acid bacteria Oenococcus oeni. Together, those molecules allow ML01 to import malic acid into the cell and convert it into lactic acid, granting ML01 the rather magical ability to perform both alcoholic fermentation and malolactic fermentation simultaneously, all by itself. In addition to speed and convenience, this one-stop fermentation is advertised as a route to fewer wine headaches. Lactic acid bacteria can produce biogenic amines, which can produce headaches and other unpleasantries in sensitive people (I’m one of them); eliminating the need for those bacteria should eliminate the biogenic amines and those symptoms.
For reasons which are probably obvious, North American wineries using these GM yeasts don’t exactly go shouting that news from the rooftops, fewer headaches or not.
What if you wanted to identify whether or not any given wine was made with a genetically modified yeast? You’d go looking for the modified gene, right? This isn’t as simple as it sounds, and not just because genes are very small. The genes that distinguish ML01 and ECMo01 are also found in other common wine microorganisms; detecting ML01, for example, means ensuring that you’re not just detecting the presence of perfectly normal malolactic bacteria.
The authors of a recent paper in the International Journal of Food Microbiology handled these problems with a conceptually simple solution to identify ML01 in mixed microbial company. They used PCR – the polymerase chain reaction, or the standard means of “looking” for genes that constitutes the bread and butter of virtually every molecular biology lab these days. PCR amplifies a very specific DNA sequence, determined by “primers” that line up with the genetic sequence you’re looking for, so that even a tiny amount of that genetic sequence in a sample can be detected. By choosing those primers to line up with the joints at either end of the signature ML01 genes – the scars left over from its engineering procedure, essentially – they could target the engineered yeast to the exclusion of both O. oeni and unmodified S. cerevisiae. By using quantitative PCR, which adds some fancy fluorescent chemistry to the basic PCR process to provide a rough idea of how much of that specific genetic sequence is in a sample, they could distinguish between large quantities of ML01 indicating that it was used for primary fermentation versus small quantities suggesting accidental contamination
The goal, in this paper, was to offer a means of establishing whether GM yeasts are being used illicitly in countries where they’re illegal as well as a test against ML01 contamination in factories where it might be produced near non-GM strains.
That’s how to find GM yeast in wine if you’re a biologist. If you’re not, you’re left with less precise methods. One: exclude wine from outside North America and Moldova. Two: exclude organic wine and wine from companies which expressly declare themselves non-GM-users. Three: recognize that the general ethos of a winery probably gives you a good idea of how likely they are – or aren’t – likely to use ECMo01 or ML01. Four: invest in a PCR machine.
*See, for example, this Australian report from 2003, or this Cornell proposal from 1996, along with numerous research projects investigating the concept.