Climate change – how big a change is it for cultivated plants? Alan Schulman, research professor at Luke and a world-renowned expert on the barley genome, describes the multifaceted challenges in future fields: Plants must survive drought, a heightened concentration of carbon dioxide and new, spreading diseases. All at the same time.
– There is no domesticated plant adapted to high carbon dioxide and drought. We have not had that combination on this planet since well before the dawn of agriculture, certainly not during the time when the humans have been cultivating and breeding plants.
The stakes are certainly high. In southern Europe, drought is already causing considerable difficulties for farmers. In Finland, water is not the most worrying issue. However, the weather conditions of the growing season have become difficult to predict. 2017 was an unusually wet year, 2018 catastrophically dry. In south-western Finland, one of the most important cultivating areas, one third of the crops were lost.
From yellow rust to the French revolution
Recently, Schulman and his team have worked on a resistance gene for yellow rust, a fungus which is causing considerable losses of wheat crops worldwide. The fungus is also spreading with climate change. However, it is not just about fungi or genes.
– If there is even a 1-2 % shortfall of the wheat in the world market because of the disease, the prices will spike. Here in Finland, people will get annoyed, but nothing more than that. In a country with a different socioeconomic situation, such as one in North Africa, you get a bread riot. The French revolution was also linked to big problems with the wheat harvest and the wheat prices went up very fast, Schulman points out.
Indeed, climate change is strongly linked to how our society will function in the future. Genetic research looks for solutions, step by step. New resistance genes, such as the one Schulman and his team found, can be added to commercial wheat varieties and brought to the market in five to ten years.
With his international team of geneticists, Alan Schulman is now modelling traits that enable plants to tolerate stress and bad conditions. Resilience is the word, which is in focus in many fields of science.
– Everyone uses the word differently. In my use, it is the ability to recover from challenge. If the plant recovers from a drought and produces some yield at the end of the year, it is resilient to stress, Schulman describes.
Scientists are focusing on the mechanisms that enable plants to survive drought.
– We analyse what the different genes and their variants do and look for variations in the plant response.
Schulman points out that plants are extremely variable and can be very resilient to drought. For example, the resurrection fern (Pleopeltis polypodioides) can wilt totally and then recover.
– It is a long way from ferns to barley and wheat and the mechanism may not be transferrable, but it is totally possible for a plant experience severe stress and recover.
Schulman gives another example of different strategies of drought resilience in malting barley cultivars.
– Some will die, but some will sacrifice the older leaves for younger leaves. Barley, wheat and rye also have parallel stems called tillers. One thing that may happen – and we have seen it – that the main stem will die but the tillers, if they are sufficiently underdeveloped, will go on. That is a form of resilience.
Scientists will now systematically dig into these adaptations.
– It is important to study these mechanisms carefully and model exactly what happens.
Schulman is collaborating with the Hebrew University of Jerusalem, using a high throughput precision drought platform, a system which enables very controlled environment and monitoring of plant reactions in different stages of drought. Schulman has used the system to study germplasm collections of barley and faba bean.
– We now have precision data, field data and data of the roots of the faba bean and we try to find out where the genes are that contribute to drought tolerance. The faba bean is a traditional crop in the Mediterranean basin and it is now coming back to Europe too.
Schulman himself is based in Helsinki, Viikki Biocentre, where collaborators are near.
– The key protein that controls the closing of the stomata was discovered here in Jaakko Kangasjärvi’s group. I am collaborating with them, taking what they learned in the model plant, Arabidopsis, and applying that in barley.
Any room for optimism?
Schulman’s group worked twelve years with the yellow rust resistance genes. Genetic studies are always time consuming processes and climate change is proceeding fast. Still, Schulman finds room for optimism. Plant genetics, genomics and breeding will help the world food production to adapt.
– I am more optimistic than pessimistic. I also realise we do not have a lot of time. We get there, but whether we get there without local crop failures, is another matter.
Schulman emphasises, that modelling also produces tools for decision makers.
– My goal is not just to understand the mechanism but to develop tools that can be used for policy. The whole history of agriculture in the 20th century has been about increased inputs. You try to minimize crop failure by adding inputs, but we come to the point where that is not sustainable. So, we need new tools, Schulman says.
From Yale to barley fields of Finland
Alan Schulman has been working in Finland since 1986, after defending his thesis in Yale. Barley was an obvious choice for him to open the secrets of the plant genome.
– The first genomic tools for cultivated plants were made for maize and rice and then it has become possible to study other species as well. I was also very interested in genome dynamics driven by transposable elements, the jumping genes, and the model plant, Arabidopsis, is not a good place to study that. Barley is. It is also a good model system for basic questions in my case.
– Barley is a good tool genetically, has seven chromosomes, so it simple genetically compared with wheat. It has big diversity set and has a wild ancestor still growing in its original range. It has also been studied a long time, so many mutations are known. Barley is important industrially. In Finland, barley is a major crop, so this is a good place to study it.