María López de la Calle: «Melatonin seems to be a promising way to improve the resistance of plants to the stress caused by climate change»
Nowadays, it is almost impossible not to hear the word melatonin when looking for solutions to help us get to sleep. Supplements containing this hormone, which is produced naturally by animals, plants, fungi and bacteria, are taking over pharmacy shelves and bedside tables.
Its involvement in the regulation of circadian rhythms and its natural origin make it a great ally in the fight against insomnia, in reducing the symptoms of jet lag and in adjusting the sleep-wake cycles of blind people.
However, this molecule conceals within it a much broader universe of biological and chemical interactions that are not limited solely to the realm of rest. The processes by which it forms a part can be translated into practical applications to, among other things, reduce the effects of stress that climate change can cause in the plant kingdom.
This is a promising reality that is still being studied and that, not long ago, was successfully explored by our interviewee today, María López de la Calle.
Her CV is impressive, and, as on many occasions, her journey began on our campus. She took the first steps of her scientific career by studying a Degree in Agricultural and Food Engineering on the Campus Terra, and, after an astonishing career full of academic achievements and professional successes, she now works hand in hand with the Secretary of State for Agriculture and Food as Technical Advisor to her Cabinet, something that is easier said than done.
We talked to her so that she could tell us what her day-to-day work is like at the Ministry of Agriculture, Fisheries and Food, why she focused a large part of her research activity on a subject such as tomatoes and how melatonin could be one of the keys to fighting the havoc that climate change can cause at a global level.
-You currently hold the post of Technical Advisor in the Office of the Secretary of State for Agriculture and Food. What does your work consist of, in broad terms?
-My work consists mainly of providing technical advice. I prepare all kinds of technical material that may be needed: executive summaries, briefing notes, etc. Also, together with my colleagues in the office, I act as a kind of link or coordination point between the office and other units of the Ministry: I look for information that may be of help to the Secretary of State or the Minister's office at any given time, and I evaluate and analyse proposals that may arise in other units.
-What was the process that allowed you to get where you are today? Because getting into this kind of position doesn't seem like an easy task...
- A boss of mine from a few years ago used to say that there are two ways to get a specific job: either because you're the right person or because you're a pain in the neck. That would be a bit of a Galician response, playing the national card. But, in reality, I got this job thanks to a fairly standard selection process, plus a bit of luck and the serendipity of being in the right place at the right time.
I passed the competitive examination for the State Corps of Agricultural Engineers, I joined the Spanish Agricultural Guarantee Fund and, at the same time, the Secretary of State appeared in the Ministry of Agriculture as such. At that moment, the need arose to create a technical cabinet, and I was given the opportunity to put my previous CV to good use in the administration. They valued the global vision of my profile, having worked in different teams, and, as I mentioned before, I went through a classic CV and interview process, something that is not usual in public administration.
-Focusing on your day-to-day work, you work directly with the Secretary of State, who is undoubtedly a very unique figure. On the one hand, she does politics, but she also does a lot of technical work, she faces the reality of the sector...
-Yes. The Secretary of State, Begoña García Bernal, is someone who has a very special sensitivity towards the land, towards women, towards farms and the real problems of the rural environment. She is someone who likes to go to the land itself, to learn about the issues first hand and to try to find solutions.
We, therefore, are also involved in all of this. Every time she travels, attends a meeting or gives a forum to a part of the agricultural sector, which is very complicated but also very important and strategic, we are there, shaping those meetings and providing her with technical advice that allows her to face her daily agenda.
-You were the beneficiary of a research grant at the University of California, Davis. Tell us, what was your experience like? Did you notice any palpable difference between research in the United States and here in Spain?
-The truth is that I did. There are certain differences.
Firstly, I can say that as a personal experience, it was terribly enriching, because it is one of the most important universities in the world, especially in agricultural sciences. Being able to work there in a world-leading centre was a real privilege. In addition, they have a series of very powerful technological tools at their disposal.
But what is the main difference?
If we restrict ourselves strictly to the field of work, Europe and Spain have indeed evolved a lot. There are top-level researchers, as well as cutting-edge technology, but I have the feeling that it is much easier to obtain research funding there.
Both collaborations with the private sector and access to funding make these processes more immediate, which means a series of facilities that are not so common here: here, we have the necessary human capital, sometimes the technological capital, but in many cases, the economic dimension is not enough.
As for my personal experience, I can say that living in California was really spectacular. I indeed decided to return to Spain because I didn't want to live there for the rest of my life; I really like being here. But I had a great time during the time I spent there, working and spending time with friends. It was an experience I wouldn't change.
-There, you investigated, among other projects, how salinity and high temperatures affected tomato plants at a molecular level. What were your conclusions?
-What we saw, first of all, is that the response of plants subjected to salinity stress and high-temperature stress separately was not the same as when they were subjected to a combination of the stresses. In the same way, it was not the addition of the stresses separately. This is especially interesting if we take into account that the stresses almost always occur in a combined way: it is very rare to have one without the other.
So, what we are trying to understand are the mechanisms that the plant puts into operation to respond to this specific situation. Therefore, in California, following on from my previous work at the CSIC, what I did was a messenger RNA sequencing study, which allowed us to elucidate the involvement of different genes in the plant's response to stress. We found activation and synergy of the proline and ascorbate pathways. When activated, they detoxify reactive oxygen species, allowing the plant to reduce stress at the cellular level.
A series of transcription factors also caught our attention, which is what “makes the genes work,” so to speak. Let's imagine that we have a book with many recipes, which would be the DNA to make different dishes, the proteins. The transcription factor would be the cook who decides which specific recipe is going to be cooked that day.
-In relation to this topic, from a distance it seems that one of your favorite objects of study is the tomato. Why did you choose this fruit to dedicate a large part of your career as a researcher to?
- Without a doubt, the tomato will mark my life since I lived buried in tomatoes for six years. The tomato is a crop of tremendous economic importance worldwide. It is one of the most important and most consumed crops and one that generates the most value worldwide.
But, on the other hand, it is an excellent research tool. It is a fantastic model in a laboratory because it has a known and public genome. It is very well studied, so we start from a broad base of work already done that allows us to advance more quickly. With so many people working on tomatoes, it is easier to generate knowledge in that environment and share discoveries.
It is also a plant that is relatively easy to handle in a laboratory with a short life cycle. Furthermore, its behaviour can be extrapolated to that of other crops of agricultural interest. I think all these factors make it ideal.
-One of your latest investigations revolves around melatonin as a mitigator of the effects of abiotic stress on plants. What were the results of this work? What other advantages can this molecule bring to the health of plants?
-Melatonin is a bit of a fashionable molecule, isn't it? As I am a bit of a fashion victim, I didn't want to miss out on jumping on the melatonin bandwagon.
In our research, what we saw was that this molecule improved antioxidant capacity, helping to reduce reactive oxygen species as well as proline and ascorbate, as I mentioned before. When applied exogenously to tomato plants, we saw that there was less stress within the cells, reducing cell damage.
Right now, it seems that this molecule is involved in the regulation of other plant hormones directly involved in different physiological processes; it is a biostimulant... In other words, it is involved in a lot of incredible processes. There is still much to discover about melatonin. Still, it certainly seems to be a promising avenue for improving resistance to biotic and abiotic stress and to situations caused by climate change.
- Many people take their first steps on Campus Terra and, within a few years, end up doing research in world-leading centres. Many of these people end up returning to continue their scientific activity on our campus. What do you think is the key to this phenomenon? What makes Campus Terra such a powerful generator of talent?
-For me, Campus Terra is an excellent place, with many things to highlight and to which I owe at least 75% of my professional achievements in life.
The treatment and the teaching quality of the campus seem exceptional to me. The teaching staff is wonderful. There is a very important relationship of closeness with the students. What's more, the staff are qualified. Many of them have relationships with universities abroad and are involved in different research projects, which gives them a very valuable international profile.
Being able to study at the Campus Terra is wonderful if we take into account that it is a campus with a very strong connection to the territory, that it is very specialized and that it is very linked to the productive sector. All this facilitates the transfer of knowledge and allows that knowledge to be based on practice.
For an agricultural engineer like me, for example, being part of this campus has many advantages. I wanted to enter the world of research. I never had any barriers of any kind on campus, from Elvira López Mosquera and Socorro Seoane, who are excellent teachers and professionals and who opened the doors of their laboratories to me, where I took my first steps, to the Dairy Products and Food Technologies Classroom (APLTA), which is a wonderful place where I also worked. Every step I took on campus was like a springboard.
I have been in contact with many other universities, and I think that the personalized treatment that Campus Terra offers its students, due to it being a relatively small campus, blurs the boundaries of what can be done. I am sure that, if a student comes up with an idea for setting up a company or launching a project, there will be someone on the other side who will listen to them, who will be open to this type of proposal.
For me, the campus is a secret that I love to tell and that I think we should all tell. Whenever I get the chance, I say that it is necessary to give Campus Terra an opportunity because it is undoubtedly a wonderful place with wonderful people.
-And finally, where do you see yourself in the near future? Have you thought about your next steps, even if it's just at an aspirational level?
Right now, the truth is that I can't commit to anything; I've only just landed, so to speak. Every time I come to work here, at the Palace of Fomento, I still look at the ceiling and marvel at the frescoes and paintings I find in the corridors. So, I still can't imagine myself in another place. I am really enjoying the process, learning a lot, settling in and trying to absorb everything I can from my colleagues and my environment.
I am very grateful for this opportunity and also for allowing myself to live in the present.