Why Genetically Engineered Grapes Would Make Great Wine
I am 99.9% sure that there will never be commercial production of genetically engineered
Wine grapes are an extremely logical crop for
Conventional breeding just isn't a viable option for wine grapes, not because it couldn't be done, but because in an industry so focused on quality and tradition, no one would consider it. The wine industry is based on specific varieties which are hundreds of years old and for which no new variety would ever be acceptable. That is true for varieties in their original appellations (e.g.
Therefore, wine grape varieties have been cloned for hundreds of years, specifically to avoid any genetic change (they have always been grown from rooted cuttings or from grafted buds). Grapes make seeds, but the seed won't grow up to be the same variety as the parent, thus they are never used as a way to grow new vines.
The Downside of Ancient Varieties
Of course, by sticking to very old varieties, wine grape growers must deal with many problems which might otherwise have been solved through breeding. Grape growers have been able to deal with some pests that attack
Why Genetic Engineering Would Be Logical For Grapes
Biotechnology is a perfect solution for wine grape issues because it allows changes to address one specific problem without disrupting any of the characteristics that determine quality. Of course, each variety would have to be individually transformed, but in our imaginary rational universe the regulatory regime would be made easier for multiple uses of the same basic genetic construct.
So, genetic engineering could be a very cool solution for various challenges for grapes. I'll list a few of the diseases that might be fixable this way.
As I described in an earlier post , the noble grapes of Europe must now be rather intensively sprayed with fungicides because a disease called Downy Mildew was introduced in the mid-1800s from New World grape species. Those same North American species have a good deal of resistance to that disease, and the genes for those traits could probably be identified and moved into the traditional, high-quality varieties.
Grape Downy Mildew infection on a leaf
This strategy might also be employed to reduce susceptibility to another disease called Powdery Mildew which requires frequent sprays or sulfur dustings even in dry environments like that of California. There are even susceptibility differences between Vitis vinifera varieties which might be able to be moved.
Grape Powdery Mildew infection of young berries
Bunch Rot is most problematic in grape varieties where the clusters are very "tight" (e.g.
Tight clustered Chardonnay is prone to rot disease
If the genes which control the development of the main cluster stem (rachis) could be identified, it would be possible to make less rot-prone versions of great varieties and thus reduce the amount of waste caused by Botrytis.
Loose clustered Merlot is less likely to rot
Viral diseases of grapes,
Fall symptoms of Leafroll virus infection
Pierce's Disease - A Potentially Existential Threat
Grapes are also susceptible to a disease which actually kills the entire vine. The pathogen is bacteria-like and is endemic to various riparian plants in the US. If an insect vector happens to move from those plants to a vineyard, it can lead to an infection called Pierce's Disease which will soon destroy the vine. In the Southeastern US this pathogen makes it impossible to grow the European grape varieties. In California infections were known, but were relatively rare because the native vector (the bluegreen sharpshooter) didn't tend to move very far into a vineyard.
Then in the 1994, a new vector called the Glassy Winged Sharpshooter was introduced into Southern California and started vectoring Pierce's disease into vineyards on a large scale. For a while it looked like this new combination would be the sort of existential threat now facing the Florida Orange industry . Fortunately, growers learned how to check the population of the vector by spraying it when it was in neighboring citrus groves, before it moved to the grapes. Also, it appears that some degree of natural biocontrol has kicked-in to keep the overall population of glassy winged sharpshooters manageable. Should this disease become a major problem in the future, a genetic engineering solution might be the only viable solution.
Voluntary "GMO labeling" Would Be Easy for Wine
Because wine grapes can be extremely valuable (e.g. as much as $10-20,000/acre), and because quality is closely connected with the location where they are grown, "identity preservation" is common in the industry. It would be entirely feasible for grapes which were or were not "GMO" to be kept separate to what ever extent was desired. So, one winery could proudly label their wine as "improved via biotechnology to provide disease resistance," while the neighboring winery could confidently claim not to be "non-GMO" if they so desired. Again, remember I'm talking about what could happen in a parallel universe where reason prevails. In our universe (as has already been demonstrated in both France and in Mendocino County California ) reason quickly yielded to the politics of fear and unfounded concerns about "genetic contamination."
So, there will probably never be commercial "GMO grapes" in our universe, but that doesn't change the fact that it is a cool concept.
Images: (top) Shutterstock/ William J. Mahnken , Colorado Chardonnay SDSavage, Grape Downy Mildew (Plasmopara viticola) image from the University of Georgia Photo Archive , Grape Powdery Mildew from Wikipedia , Rotting Chardonnay SDSavage, Merlot from Naotake Murayama . Leafroll virus from Oklahoma State University
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