Santiago Pereira: «Galicia has preserved a series of genetic resources with a uniqueness that is reflected in the quality of the final products»

Genetic diversity has been a fundamental factor for the survival of different species since the beginning of time. Now, in the hostile environmental context in which we live due to climate change, it is even more important, if that is possible.

And Santiago Pereira Lorenzo knows this firsthand. Professor of Plant Production, lecturer and researcher at the Campus Terra, head of the Agronomy and Animal Science research group and co-director of the Chair of Bread and Cereal, Santiago Pereira has spent more than 35 years pouring all his efforts and knowledge into the use and preservation of the genetic resources of plant species, such as the chestnut tree.

Today we invite you to witness the journey of a passion that began to manifest itself from the cradle and that has resulted in an astonishing professional career. And one that, of course, we predict will continue for the years to come.

-Why plants? What led you to delve so deeply into that universe? Is it vocational or rather one of those coincidences that life sometimes has?

-It's a bit of everything. My family had a farm, a furancho, where Caíño wine was made. Curiously, I had the opportunity to research the Caíños to participate in the discovery of the origin of 'Caíño Blanco' and the key role that 'Caíño Bravo' played in the Galician grape varieties.

Similarly, in my house, we had a pear tree that was over 100 years old, grafted by my grandfather, of the Galician variety 'Urraca.' I was also able to study this particular variety and see that it is one of the most important in Galicia. Today, we can buy it in nurseries with a guarantee of varietal identity.

So, yes, they are coincidences of life, so to speak, but it is undeniable that there was an initial basis built a little from the cradle, wasn't there?

-Some of your research was very much focused on crop biodiversity. What are the biggest challenges today in conserving and improving the genetic diversity of plants?

-I have participated in the evaluation and establishment of the germplasm banks of Galician varieties in our community, and I know this field firsthand.
But what are the dangers that these living collections may face?

Well, as an example, I could mention what happened with a collection of chestnut cultivars that would later give rise to the Chestnut from Galicia PGI. We set up the collection on a plot of land in Sergude, and I remember that it had involved an enormous economic and personal effort. After a while, we were told that it had been devastated by wild horses that had entered the property, and much of the effort that had been put in was lost.

This experience, together with others, highlights the difficulties involved in the preservation of genetic resources, especially those that require living plantations. In fact, there are few alternatives for their conservation.

In addition, financial resources come into play, the large fluctuations of which pose a real challenge to the long-term maintenance of these projects.

-Genetic editing is a recurring theme in the latest interviews we have done. In your opinion, to what extent can the genetic improvement of crops contribute to sustainability and adaptation to climate change?

-I believe that technology is what will make it possible to solve all these great challenges in the future. We have very serious challenges, such as feeding a growing global population with limited resources in the context of climate change. Therefore, all tools are very necessary.

In fact, it is something we see continuously in the articles we review. These tend to integrate classic technologies with the most cutting-edge, whose potential we still do not know to its full extent.

-You were talking earlier about the European chestnut and other fruit-related species. What impact can the results of that research have on the sector? Is it possible to find common lines?

-They are really very different. In the last year, we have not only been working on fruit trees but also applying molecular markers. We have carried out, and are carrying out, studies of genetic diversity in other herbaceous species. They all have their particularities, such as the reproductive system, the geographical context or the degree of domestication of the species, for example, which means that the study and work with each species is different.

Furthermore, I would say that science, in this respect, still has a long way to go. There are many aspects that we come across that challenge us every day: not everything has been done. For example, last year a proposal arrived from Switzerland related to the chestnut tree, which was one of the first species I worked with.

In this research, we worked with samples from Australia to see if its origin may indeed be in Switzerland. To do this, we used a database of around 3000 genotypes from recent years, also working with France, Italy and Portugal.

Then we determined what is nothing, if not a very surprising and interesting story. A chestnut tree reproduced in Switzerland is taken to Australia, and today, it is cultivated there, on the other side of the world. So, we asked ourselves a few questions, like what is that domestication process like?

The research we carry out has an impact on the products we consume, making them more diverse, more accessible and, at the same time, of higher quality.

-We normally talk about globalization in economic or cultural terms. Still, as a result of what you are telling us, we are rescuing the perspective of globalization understood from the field of science. This interconnection between research groups makes it possible to create a body of common knowledge, something of great relevance...

-Absolutely. What's more, this process happened very quickly.

I remember an article that came to us recently and is in the process of being evaluated, in which several scientific groups are testing coffee varieties from different corners of the globe on various continents in order to understand their ability to adapt to climate change.

So, then you reflect on the logistical capacity in the project to be able to carry out this study, the responsibility to agree and be able to carry out research of this magnitude.

-The work carried out throughout your career had a substantial impact on PGIs and PDOs, but also on the traceability of crops. What was the process of taking research from the laboratory to the field and industry like? Is it a complex journey?

-Indeed. That was another surprise in my life, the fact of starting to collaborate in the Bread and Cereal Chair with the Professor of Food Technology at the Campus Terra, Ángeles Romero.

We worked on an initial proposal that started from scratch, so to speak, and that arose from a company that was interested in improving the quality of bread, Galician bread, using varieties of wheat from the country.

From that moment on, we began to work in this field, and we demonstrated that Galician wheat varieties had a series of very marked differences with respect to commercial wheat varieties. Furthermore, there was a genetic basis that supported this hypothesis and that effectively made it possible to differentiate what is really Galician bread.

This technology, therefore, allows us to trace or follow the production and use of Galician cereals right through to bread making. We then registered a patent that has already been accepted and that we are trying to activate, since the PGI must control that Galician bread incorporates at least 25% of local wheat.

This was a very nice journey that I made, moreover, with all the colleagues and collaborators of the Chair of Bread and Cereal who were integrating different methodologies, such as the study of starch grains through microscopy quantified using neural networks, which determined that this uniqueness of Galician wheat is evident in the quality of the bread itself.

There is, in fact, a scientific basis behind the quality and uniqueness of Galician bread that supports our ability to defend, produce and protect it.

-Only a Galician university could create a Chair of Bread and Cereal that would also demonstrate that, in fact, behind everything you have told us, there is a scientific basis that turned the idea into reality: here, bread is something else.

-It's very clear. But we also have to highlight all the previous work, not only of our farmers and bakers who knew how to keep all the knowledge of its production and elaboration but also of all the people who later preserved the seeds in the conservation centres.

The work of our students was also essential. They were very involved in the whole process and defended their doctoral theses as a result of the various projects in collaboration with the Chair.

So, it really surprises me that all these experiences, from very diverse people with very different specialties, ended up defining what Galician bread is today and providing very valuable knowledge that we, in the end, make available to people who want to make use of it.

There is a long way to go in this respect, something that we also see in other denominations of origin, such as that of the Chestnut of Galicia or the various ones related to wine. There is a common theme in all these areas that shows that Galicia preserved a series of very ancient genetic resources of great value, with a uniqueness that is reflected in the quality of the final products.

-Of the research projects you are currently leading... Is there any that particularly motivates or excites you?

-At the moment, we are very involved in the Bread and Cereal Chair, although I have to admit that the chestnut line will never cease to amaze me after 36 years of working on this species.

I am also correcting a thesis on a very curious species of walnut tree, native to tropical areas, and which few people knew about until now, as part of the PhD Program in Agriculture and Environment for Development at the University of Santiago de Compostela. For me, it is of enormous value that studies in these areas are disseminated to the international scientific community.

-In previous interviews, a common variable emerged, which is the case of plant improvement using gene editing. What role do these new technologies play in this field, and what ethical and regulatory challenges do they face?

-Due to regulatory issues, we have significant limitations with this tool, especially in Europe. However, it is a technique that is widely used worldwide, and we are consumers of products that have been genetically modified. The impact it has on our society is very significant, and it is also a question of food security and control.

Technology is constantly advancing. In other species, such as vines, classical methodologies are used in combination with new technologies to obtain new varieties through massive hybridization, varieties that are genetically almost identical to the varieties we know but which incorporate resistance to disease without using genetic editing.

I believe that all these methodologies are necessary because they allow us to explore different avenues and, at any given time and in any given situation, one or the other may be necessary.

- And finally, you have collaborated for years with institutions in several countries. How did this relationship with other international centres enrich your research?

-They were crucial for me. I will always remember the first one I did, in England, a place with a culture I dreamed of. At that time, it was a scientifically more advanced society than ours in my field of knowledge, and the people were very welcoming. I learned techniques that I was later able to apply here. These kinds of experiences contributed a lot to me on a scientific level but also a personal level. Everything adds up.