GMO yeast in wine and how to find them

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.

 

“Fit-for-purpose” yeast from the AWRI

The Australian Wine Research Institute (AWRI) has created a quick-read summary page on their ongoing project to develop “fit-for-purpose” yeast: yeast strains designed to facilitate specific flavor profiles for specific applications. They’ve already developed and released (through AB Mauri and Anchor) several strains including two interspecies hybrids — Saccharomyces cerevisiae crossed with S. kudriavzevii or S. cariocanus — and low H2S-producing strains. More are being tested in Shiraz and are likely to emerge over the next 3-5 years. The AWRI is making a point that this research is Aussie-focused — their argument is that similar work being done elsewhere is creating yeasts not necessarily suitable for Australian wine styles — but no doubt their results will end up helping non Australian-industry levy payers, too. It’s worth noting that their development strategies rely on good old traditional genetics strategies and not genetic engineering. They’re not inserting genes from other species into yeast; they’re breeding different yeasts together, encouraging yeast to mutate (that is, spawning lots of random changes in their DNA with chemicals and stress) and looking for useful mutations, and using contemporary genetics to understand which genes do what. For a quick explanation of why I’m glad that they’re sticking with traditional genetics strategies instead of creating GMO yeast, check here.

Whether you’re excited about the prospect of using tailor-made yeast to target particular flavors or whether you’re in the don’t-inoculate-my-wine camp and hold that fermenting with yeast from the environment is the only or best way to terroir-full wines, it’s hard to argue that knowing more about yeast is a bad thing. Developing new commercial products may be an increasingly major research driver as scientists need to look for support from private sources. Furthermore, ending up with a new product you can hand to someone is a tangible way of saying, “Here, look; our research really is applicable and relevant to real-life winemaking!” Regardless, projects like these continue to provide an umbrella for basic research on yeast genetics and wine flavor development. And maybe not tomorrow, and maybe not next year, but in the long run, that’s something that ends up helping everyone.

Hooray for Oregon: two counties vote for no GMOs

Oregon’s Josephine and Jackson counties have both, at least per the preliminary counts (official ones will take weeks), voted in favor of banning the planting of GMO crops inside their borders. Find accounts of the highly contested ballot measures at Oregon Live and The NationCommercial GMO wine grapes aren’t yet available, but it’s likely they will be soon with research in that direction underway in Florida and France. GMO wine yeast are already for sale — ML01, which has the bacterial genes for malolactic fermentation — though whether the ban applies to its use, since the yeast aren’t a crop per se, is a question.

Plenty of pro-GMO publicity relies on the lack of scientific proof that GMO foods are in any way harmful to eat or nutritionally inferior. That’s true, but it’s also not the point. In my opinion, the strongest reasons to oppose GMOs are:

Biodiversity – GMOs are usually designed to be more disease-resistant, more vigorous, and/or higher-yielding than non-engineered varieties, which means that they have a competitive advantage in the wild. With yeast and bacteria, or if GMO plants escape from cultivated fields, that means that they’ll out-compete native varieties, which means that we lose biodiversity. Biodiversity is good. Natives, and rare variants among natives, may harbor as yet-undiscovered genetic and biochemical solutions to diseases or bioengineering problems. Diversity makes systems more resilient to disease and changing environments. And there’s the aesthetic argument: life is beautiful in its many shapes and colors.

Food security and sustainability (the biology side) – At least 70% of the US corn crop is Monsanto “Roundup Ready,” and something like 90% of the soybean crop. What if a disease struck to which Roundup Ready X was specially susceptible? Bacteria and viruses mutate to adapt to their hosts; this isn’t that unlikely. Not only do we need farmers growing a diversity of varieties, but we need to ensure that in the case of wind-pollinated crops (like corn) hypercompetitive genes don’t spread to infiltrate even non-engineered crops.

Food security and sustainability (the economic side) – GMO crops are patented. Growers can’t legally save their seed from one year to replant the next; they’re obligated to pay the giant corporation to provide their next crop and set of paychecks. Monsanto has aggressively defended this “right.”  I understand that the economics here are complex, but I can’t see a way to slice this argument that doesn’t come down to feeding mega-business, collecting power and money in the hands of the few who are already powerful and wealthy, protecting and encouraging increased commodification and commercialization and engineering of our food supply, and hurting everyone who A) isn’t a corporate billionaire and B) eats. And if all of that is a bit much, just imagine being the family farmer who gets sued by Monsanto. The layers of anti-sustainability, anti-farmer, pro-big business unprintable evil this represents are too many to explore in full here, particularly because I may need to go out and chop some wood now just to burn off the anger I feel thinking about this nonsense.

All of that is in addition to the possibility that GMO crops may pose some danger to human or animal health, both of which are still untested possibilities insofar as we haven’t been studying them long enough for a full assessment.

The Josephine and Jackson measures still need to be put into effect and enforced, neither of which are yet certain bets. But the vote is a definite step in the right direction and, more importantly, sets a precedent for other counties in other states. More reasons why, along with some very fine pinot noir, I’m proud to be an Oregonian.