Editing grapevine in Italy

A vineyard in northeast Italy (from M. Morgante’s Ppt)

CRISPeR Frenzy is pleased to publish the full text of the presentation held on June 6 by Michele Morgante (Università degli Studi di Udine) at the Virtual Workshop on Innovative Biotechnologies and Regulatory Approaches organized by the US Embassy in Rome and USDA.

One may wonder why we need to change things in agriculture. And when one looks at such an idyllic picture of a vineyard in the region where I live in the northeast of Italy, one could think that there is no need to change. However, as usual, the devil is in the details and viticulture is a highly profitable agricultural activity but also an activity that has a high impact on the environment.

It only uses a bit more than 3% of all the cultivated land in Europe, but it employs 65% of all fungicides utilized in European agriculture. The reason for such intense use of chemical products to protect plants, mainly from fungal infections, is related to the fact that in viticulture, unlike in most other crops, we are still growing varieties that are decades if not hundreds, and sometimes up to thousands of years old.

So there has been a very little contribution of modern plant breeding to modern viticulture, and if you want to protect the plants from enemies, such as fungal infections, you have to rely on the use of chemical products. And you cannot rely on genetic solutions to provide resistance against those fungi. The breeding of grapevine has been limited. But the only breeding that has been carried out so far has been through traditional breeding.

In order to respond to the demand for more sustainable practices in viticulture, my Institute and my University have started 20 years ago a traditional plant breeding program to develop completely new winemaking varieties with a goal of obtaining varieties that are resistant to powdery and downy mildew, the two most devastating fungal pathogens in European viticulture.

Two pathogens that were not present in Europe before the 19th century. So that’s why varieties are not resistant to those pathogens, that were not present here when those varieties were developed. We have gone through a long process and we have reached the point of producing today 14 varieties that have been protected, for the plant variety protection scheme, that are now on the market in Italy, in Europe and some of them also in the US.

Those varieties are interesting, both because they have resistance to powder and downy mildew, and also because according to our opinion, they also have good enological characteristics, so to speak in plain terms, they make good wine. But it’s not easy to introduce such varieties into a highly regulated market system such as winemaking.

The main reason being that there is an exceedingly high value connected to traditional varieties. So if you want to buy Brunello or if you want to buy Barolo, Brunello has to be made with Sangiovese grapes, Barolo has to be made with Nebbiolo grapes. And thinking about introducing new varieties into such high-value wines is really challenging, not only because it will require major changes in the regulations that underlie the production of these high-value wines.

But also because admittedly, there is a lot of knowledge that has been put into making excellent wines such as Brunello or Chianti from Sangiovese, such as Barolo or Barbaresco from Nebbiolo for centuries of winemaking practices. So thinking today that we could set aside those varieties and start to make these high-value wines with completely new varieties is not realistic.

So if we want to deeply impact the Italian and European wine industry, we have to be able to preserve traditional varieties, making them resistant to pathogens in order to combine tradition and environmental sustainability. So do the new breeding technologies provide us with a possible solution to this dilemma? Maintain traditional varieties, but improve them to make them resistant to diseases?

The answer is yes, we have two technologies that are very interesting if we talk about disease resistance. One is cisgenesis, which consists of the introduction through genetic engineering of a gene that comes from the same species or from a species with which it can be crossed in its native form without any change to its original structure and sequence.

In the end, cisgenesis produces very similar modifications to those that we have obtained through crossing in our traditional breeding scheme. So it’s a perfect replacement for the widely used integration of disease-resistant traits from wild relatives into cultivated varieties through backcrossing. In a species like grapevine, the reasons for using cisgenesis are multiple.

First, it’s faster. With a long generation time of grapevine, going through a backcrossing scheme is time consuming. Second, it’s more accurate, we only introduce the individual genes, without the risk of bringing in from the wild relative other undesirable variants of other genes.

But most importantly, unlike what happens when we go for a crossing, if we introduce the gene through cisgenesis, we leave the starting genotype or variety completely unchanged, except for the disease resistance characteristic. And that’s perhaps the most important thing.

The other technology that, of course, is of extreme interest is genome editing through CRISPR/Cas. It produces modifications that are identical to those that could occur spontaneously. It’s a perfect replacement to the use of induced mutagenesis and, even in this case, the advantage is that it’s faster, it’s more precise, and it doesn’t require any crossing, which means that it can preserve the starting genome type or variety.

So how would we go about applying these two technologies to improve traditional varieties? For example, instead of starting from Sangiovese, making crossing and producing what would be a completely new variety (with all the attached problems of a new genotype in terms of winemaking), if we use cisgenesis, we could take a downy mildew resistance gene, exactly the same gene that we use in our traditional breeding scheme, put it into Sangiovese and we would immediately obtain Sangiovese that now carries a downy mildew resistant strain.

For editing and powdery mildew resistance, we know the identity of a gene which is a susceptibility gene to powdery mildew. When that gene gets knocked out, the variety becomes resistant to powdery mildew. So again, instead of using crossing, we could simply use genome editing to obtain knockout mutation on both copies of the gene and make Sangiovese resistant to powdery mildew.

So, it all appears to be very simple. But the reality is that when we talk about these innovations, it’s not sufficient to think about excellence in research. It’s not sufficient to think about a system that efficiently transfers knowledge from the laboratory to the market, through, for example, nurseries and through farmers.

We have to be especially careful about the existence of an appropriate regulatory framework. And perhaps most importantly, we have to think very carefully about the acceptance of these new products by the consumers. We can go through all the process, but if the consumers won’t buy the products, then the effort will be wasted completely.

So I want to close my presentation by briefly touching on these two aspects. What are today the regulatory hurdles? When it comes to winemaking varieties, there are major hurdles even for the varieties that are obtained through traditional breeding. In Italy, they are still treated as interspecific hybrids, even though they only have 5 to 10% of wild species genomes. So because they are classified as interspecific varieties, they are not allowed to be used in DOC or AOP productions which are the high-value wine productions.

In Italy we have an additional regulatory hurdle: agricultural decisions are put in charge of regional governments, so we have to go through a different regulatory approval process for each of the 21 Italian regions, which is a major nightmare. When it comes to using new breeding technologies we have even bigger hurdles.

Cisgenesis is considered equivalent to transgenesis despite the existence of an EFSA opinion saying there is no additional risk in comparison to traditional breeding. Genome editing is also treated as transgenesis based on the European Court of Justice ruling of 2018, which is unenforceable because edited plants can be undistinguishable and untraceable.

We have new hopes coming from the recently published study that the European Council commissioned to the European Commission. It says that the new breeding technologies do not pose additional risks in comparison to traditional breeding and do offer opportunities for making European agriculture more sustainable and more competitive.

Hopefully this will lead to a revision of the current legislation, so that the products of editing and cisgenesis will be regulated differently from GMOs. Then there is the problem of how to change what is today a negative perception in Europe of the value of innovation in agriculture, especially genetic innovation.

We have to explain quite clearly that the new breeding technologies, together with the digital technologies, can be at the center of a revolution in farming that can lead to more sustainable, more productive, higher-quality agricultural products. Through the new breeding techniques, we can achieve the difficult goal of combining productivity and sustainability.

And we can provide clear examples such as the case of winemaking grapevine varieties, where we can use innovation to preserve those traditions that are so precious to European consumers and to preserve the agricultural and food diversification that again is considered so precious by European consumers.

Finally, when I think about the future of regulations in Europe, I hope the future decisions will descend from logical and not ideological considerations. We have to try and leave ideology behind us and we have to consider all implications and consequences of decisions, on the consumers, the farmers, the world trade and the environment, and hopefully find a solution that is a win-win solution for all of the actors in the system.

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