Addressing the mechanism of action behind the adaptation of root growth to environmental conditions and other influencers

Dr. Crespi

An Interview with Dr. Crespi, Director at the Institute of Plant Sciences, Paris-Saclay, France.

Berlin, Germany

March 18, 2015


Dr. Crespi

Dr. Crespi

Dr. Martin Dario Crespi is Director at the Institute of Plant Sciences, Paris-Saclay (IPS2), Orsay, France. He received his habilitation from the University of Paris-Sud (University of Paris XI), Orsay for his work on “The role of bacteria in plant morphogenesis and differentiation.” He further holds a doctorate degree in biochemistry from the University of Buenos Aires, Argentina. In 2003, he served as Group Leader of the “Regulatory RNAs and Root Architecture” team, first at the Institute of Plant Sciences, Gif sur Yvette, France and since 2015 at IPS2. Dr. Crespi’s key scientific interest is deciphering the mechanisms of action of different riboregulators on root growth and development by combining cell biology with genetic, genomic and molecular approaches. The remarkable developmental plasticity of roots, their precisely-defined gradient of differentiation, and their capacity to form de novo meristems make them an attractive model to reveal novel mechanisms in adaptive developmental regulations to the environment. We spoke with Dr. Crespi during the European Root Health Forum in Berlin 2015.

Video interview with Dr. Crespi


How can plants adapt to fluctuating soil environments?

I think plants have learned to adapt to fluctuating soil environments since a very long time. It is the main difference between them and animals: animals are born and just grow according to their body plans with all organs formed, whereas plants grow – and at the same time – perceive the environment and adapt their growth to it through the generation of organs (leaves, roots and flowers after germination). Roots are a fascinating example in this sense because you can find more or less lateral roots, as well as longer or shorter roots, based on the soil environment they grow in. We are just now starting to enter into the discovery of the molecular mechanisms behind those developmental decisions. And that is what I find especially interesting about analyzing this root plasticity.


What are the key mechanisms of adaptation?

I think there are many mechanisms of adaptation. We will have changes in the number of lateral roots and the length of the lateral roots, which will determine how much root surface will be available for the interaction with the soil. In all of these adaptations, particularly interesting is that there are several genes that can quantitatively modulate the final size of the root system. The roots can perceive the soil environment and adapt to it in the best way. You can have genetically identical plants with the same DNA sequence, growing in different environments, and they will show different growth patterns – suggesting that the environment can really influence the way in which they grow. I think the quest to understand these mechanisms is now coming up because we have the possibilities to molecularly dissect all the genes and all components involved in these responses. This is an emerging field in which we need to combine mathematics, statistics, modeling, physics and biology in order to try to understand this process of organ generation (roots in our case) better. The view we have is that biology is entering this new century with a very new capacity to dissect molecular mechanisms, unlike 20-30 years ago, when the tools were not available and biologists were mainly doing “classical” experiments (biochemical purifications, molecular genetics). Now we are moving biology more and more into physics and mathematics in order to understand the basis of life and of life’s decisions. Understanding the molecular mechanisms is very exciting information to come. It will allow us to really model how roots can control their growth and how these decisions have been made.


Why did you choose a model plant to analyze the effect of Sedaxane?

Model plants, such as Arabidopsis thaliana, were developed in order to have the capacity to bridge the tools from modeling to molecular biology in a simplified system. We know all genes of A. thaliana and how they interact. Based on this, we can do predictive biology, trying to estimate how globally the genes and the root system evolve when we stimulate them with different environments. It is very important to do this in model plants, as their genomes are not as large as those from crops and are easier to handle to understand these detailed dissection mechanisms. However, the information we get with the model plants has to be translated into crops. In this way, we will hopefully find the rules governing the underlying cellular and organ mechanisms which would also apply for “real crops.” In our research, we would like to see what effect sedaxane has on plant growth of Arabidopsis thaliana. If it has an effect, we can analyze it, model it, and look at the underlying dynamics on growth control. We can also analyze how the different cell types respond to this active ingredient (AI) and modulate how, for example, stem cells, at the origin of the future organs, will respond to this kind of AI. I think it is very interesting that we now look at an AI that is stimulating growth and development instead of just controlling a pest. This is what we can learn using these methodologies and later translate this research and innovation into crops.


Dr. Crespi was interviewed by Dr. Melanie Goll, Technical Innovation Manager, Syngenta. Melanie holds a Ph.D. in plant pathology and focuses on seed treatment development, especially fungicides and nematicides.