VIA Community Guest Blog: Wine Yeasts and Genetic Recombination in Vines by Anna Carnera

Ep. 396 Roddy Ropner
September 16, 2020
VIA Community Guest Blog: Scienza Time by Anna Carnera
September 16, 2020

VIA Community Guest Blog: Wine Yeasts and Genetic Recombination in Vines by Anna Carnera

Vineyard grape pergola in Chianti region. Tuscany, Italy Europe.

So, GMOs, cisgenesis, and genetic engineering, in general, are the future. But there is a problem. It’s easy to talk about genetic engineering but it’s difficult to do it. Nowadays, we work on plant calluses modifying the cells inside with bacteria or viruses. The difficulty is then to move from a callus to a vine. While you can do it easily in tobacco, corn, or potatoes, in the vine this is the most difficult part because the vine is an over-selected plant, so it has lost the possibility to go from a callus to an organized plant.

Professor Attilio Scienza

We at the Italian Wine Podcast are super excited to have a "Scienza" blog to offer up from the amazing Anna Carnera. The multi-talented Anna spends much of her time bringing wines made from Italian and Spanish native grapes to Canada, Japan, and Russia. Here, she's taken a moment to flex her language skills and translate some fairly technical information from Professor Attilio Scienza.

This time around, Stevie Kim and Professor Scienza took a few questions from David Pinzolo of Three Tier Partners in Episode 343 of the Italian Wine Podcast. David asked about "wild" and commercial yeasts, GMO plants, and trait selection in grapevines. Listen to the original Everybody Needs a Bit of Scienza edition of the Italian Wine Podcast, Episode 343.

Translation by Anna Carnera

Stevie: OK, let’s do this. Hi everybody. Welcome to Everybody Needs a Bit of Scienza. I’m here with Attilio Scienza, our guiding light and chief scientist for VIA. Today we have a question from VIA Community David Pinzolo (maybe he has some Italian ancestry).

Scienza: Yes, yes, definitely.

Stevie: So, he is co-founder of Three Tier Partners and he is also an Italian Wine Ambassador. He actually sent a very very long series of four-part questions, which I have already read to Scienza. You know how he [Scienza] gets: once he starts talking he never stops so…

Question number one.

Do you foresee a far-reaching change in the trellising systems used in vineyards away from vertical training and a return to pergola/horizontal systems as a result of climate change? If so, how would you expect the characteristics of the resulting grapes to change assuming the growers are continuing to focus on quality and not quantity. Are the new vineyards set up to carry "proper yields" and planted to the proper vine density per hectare?

So that was the first question, here’s the second.

What do you think of the concept of wild yeast and/or spontaneous fermentation with the assumption that such technique gives a wine more product specificity? I have heard many producers talk about this practice with the belief that it works a little bit like a zip code; if done regularly and scrupulously it will yield wines that will speak of the area but even more so of the vineyard and the specific winery. Do you agree?

Question number three.

How should one interpret the most recent studies published in the U.S. which seem to indicate that, once commercial yeasts have been used in the fermentation area, they are so aggressive that fermentation started spontaneously with indigenous yeast will, in short order, be overrun by the ambient commercial strains, thus becoming a fermentation under the control of the non-native strains?

And finally…

What is the difference, in your opinion, between genetically engineered vines and vines that are modified via more traditional crossing and propagation methods? Are the two essentially the same except that, in a very simplified fashion, the former involves a specific question and the attempt to reach the answer by working on the DNA sequence of the plant whereas the latter involves taking two plants with desirable characteristics, mating them, and hoping that those desirable characteristics will emerge in the resulting "offspring?"

Oh my goodness, it sounds like an MW question. Attilio wake up! Now you can wake up!

Scienza: I’m ready!

Stevie: OK, so let’s start and let’s be concise.

Scienza: First, I want to thank David for these questions that are really interesting, really relevant and-

Stevie: -This boy is up to date!

Scienza: Uh? Yes, he is.

Stevie: Actually, he’s not really a boy anymore but-

Scienza: -These questions are really precise and interesting for all wine consumers.

The first question is about the reintroduction of the pergola because it provides protection to grapes from the unfavorable effects of solar radiation. So, the answer is “yes,” we can adopt this system again in the areas where it was already widespread, or it was almost the only system used. I’m thinking about Soave, Trentino-Alto-Adige, Abruzzo, Apulia and Sardinia.

But in the past, the pergola was synonymous with quantity and not quality. Now, things have changed a lot, because those who are using pergola do so with a different aim. They produce much less wine, but the quality is higher. Anyway, the main problem of returning to the pergola is the expensive cost, as it is not a mechanical system. There are always other alternatives such as espalier vines.

The second question was about yeasts - in particular, their role in spontaneous fermentation. Firstly, we have to make it clear that yeasts don’t survive on the plant but on the grape. The environmental conditions are changing so this blastomycete can’t…

Stevie: Sorry, what? Can you repeat?

Scienza: Yeast is a blastomycete, a fungus, a unicellular organism. So, nowadays parasite control and climate change have greatly reduced the yeasts present on grapes themselves. Yeasts are currently present on bumblebees, who are living in the vineyard. While they are flying, they accidentally break the grape and introduce the yeast. Moreover, yeasts are also currently present inside cellars, in the air, in barrels, on the floor, inside tanks, where there is a great contamination.

But these yeasts are no longer the same as those in the past because the continuous use of the selected ones has, over time, changed the whole genetic structure of indigenous yeasts. Maybe in some isolated areas we can still find wild yeasts, such as in the Caucasus or in some Greek Islands where they have never used selected yeasts. Otherwise, the ones found in our cellars are selected yeasts.

Spontaneous fermentation happens in two phases. In the first stage of this process we have sugars transformed by yeasts other than saccharomyces, that die off when the must has reached five to six percent alcohol. After this, saccharomyces yeasts take over and finish the process. So, what is the role of these wild yeasts at the beginning of fermentation? They give a particular aromatic imprint.

The last question is about genome editing, which is a kind of cloning. The use of genome editing is to act on a gene as nature would act. But, while nature can modify randomly as it’s a spontaneous phenomenon, man can select the gene that interests him in a more precise way by removing or activating it inside the DNA of the vine.

And the result of this process is different between GMO and cisgenic plants. In cisgenic plants the DNA is modified by adding one or more genes that come from plants belonging to the same species. On the other hand, GMO organisms contain genes that come from other species. For example, in the past, some corn plants were modified by adding a gene from a bacterium that is lethal to insects.

So, GMOs, cisgenesis, and genetic engineering, in general, are the future. But there is a problem. It’s easy to talk about genetic engineering but it’s difficult to do it. Nowadays, we work on plant calluses modifying the cells inside with bacteria or viruses. The difficulty is then to move from a callus to a vine. While you can do it easily in tobacco, corn, or potatoes, in the vine this is the most difficult part because the vine is an over-selected plant, so it has lost the possibility to go from a callus to an organized plant.

Stevie: Ok, so I went for a coffee and now I’m back and he must have finished. So, have you understood the level of our ambassadors? They are very good, these questions are interesting, technically very valid.

Scienza: yes, undoubtedly, I have. These questions were really interesting and appealing for all.

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