Plant Research Shows: Roots Determine Their Growth Path Surprisingly Early
Freiburg, 30/07/2026
University of Freiburg researchers show how young lateral roots determine their initial growth strategy. This strategy governs how plants initially penetrate the soil in search of water and nutrients. The results could contribute over the long term to making crops more resistant to stress factors like drought.
The root architecture of a plant is crucial to its ability to adapt to environmental conditions. The foundation for this architecture is laid by lateral roots that branch off from the main root. University of Freiburg researchers have now succeeded in demonstrating how and when the growth direction of new lateral roots is determined.
A key factor in this process is how a young root processes information about gravity: Within a surprisingly short time window of just a few hours, sensory perceptions are transformed into the plant’s long-term architectural traits. The findings were published in the journal Proceedings of the National Academy of Sciences (PNAS).
When gravity perception takes effects
‘We were not only interested in how plants perceive gravity’, says Prof. Dr. Jürgen Kleine-Vehn, speaker of the Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies and professor of molecular plant physiology at the University of Freiburg. ‘We wanted to understand when in the course of development this information takes effect. Our results demonstrate that this happens within a limited developmental time window.’
Plants explore the soil using a wide variety of strategies in their search for nutrients and water. Some species form deep root systems in order to reach water even during periods of drought. Others remain closer to the surface, making particularly efficient use of the nutrient-rich upper soil layers. The structure of a root system thus plays an instrumental role in how resilient a plant is to environmental stress.
“We were not only interested in how plants perceive gravity. We wanted to understand when in the course of development this information takes effect. Our results demonstrate that this happens within a limited developmental time window.“
Prof. Dr. Jürgen Kleine-Vehn
Speaker of the Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies and professor of molecular plant physiology, University of Freiburg
A protein as the key factor
Each newly formed lateral root initially grows into the soil at a predetermined angle. This growth direction shapes the early architecture of the entire root system. However, it was previously unknown how the plant selects this initial growth direction To answer this question, the researchers investigated the gravity perception of young lateral roots.
In the process, they identified the protein SHOOT GRAVITROPISM 9 (SGR9) as crucial for determining this time window. In the absence of SGR9, young lateral roots perceive gravity with a delay – but they do not lose this perception permanently. They continue to respond to gravity later on, but the initial growth path they take during their early developmental phase is permanently altered.
Sensory perception becomes a stable developmental decision
‘That, precisely, was the key finding for us’, explains Sophie Farkas, doctoral candidate in Klaine-Vehn’s research group and lead author of the study. ‘We do not have to block the perception of gravity in the root. Simply delaying it is enough to permanently alter the initial stable growth path of a lateral root.’
The study therefore shows that the crucial factor for the development of a lateral root is not only how it perceives environmental information but above all when it processes that information. During a brief developmental time window, a fleeting perception of gravity becomes a stable growth decision. Only later do other mechanisms take over, allowing the plant to adapt the direction of its roots flexibly to changing environmental conditions.
General principle of developmental biology
The new findings are not only interesting on account of the better understanding of root biology they provide; rather, they illustrate a general principle of developmental biology: At some point, organisms must translate information from the environment into a permanent form. As the Freiburg researchers demonstrate, plant roots make use of a clearly defined developmental time window for this purpose.
In the long term, this knowledge could help researchers to better understand how different root architectures develop and how they can contribute to the adaptation of crops to drought or nutrient-poor soils.
Prof. Dr. Jürgen Kleine-Vehn
Prof. Dr. Jürgen Kleine-Vehn is professor of molecular plant physiology at the University of Freiburg’s Faculty of Biology. He is a speaker of the Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies and a member of the Cluster of Excellence Future Forests. In his research, he studies how molecular signals are translated into coordinated growth decisions, thus determining plant architecture.
Sophie Zoe Farkas
Sophie Zoe Farkas is a doctoral candidate at the University of Freiburg’s Department of Molecular Plant Physiology. Her research focuses on the mechanisms by which plants control the architecture of their root systems.
CIBSS
In the Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies at the University of Freiburg, researchers from biology, medicine, chemistry, physics, law, and engineering are working together to investigate how living systems process signals and use them to make decisions. CIBSS is receiving funding from the German Research Foundation (DFG) within the context of the Excellence Strategy of the federal and state governments.
Future Forests
In the Cluster of Excellence Future Forests at the University of Freiburg, researchers from the natural sciences, social sciences, and humanities are working together to investigate how forests respond to global change and how their resilience can be strengthened over the long term. Future Forests is receiving funding from the German Research Foundation (DFG) in the context of the Excellence Strategy of the federal and state governments.
Further Information
- Original Publication: S. Z. Farkasa, F. Grippoa, D. Oulehlovác, A. González-Delgado, S. Noura, S. Molazeinali, K. Wabnik, M. Fendrych, S. Waidmann, J. Kleine-Vehn: SHOOT GRAVITROPISM 9 links sensory timing to the initial lateralroot growth angle. In: Proceedings of the National Academy of Sciences (PNAS).
DOI: https://doi.org/10.1073/pnas.2536276123