Light for Root Development

The plant biologists Dr. Stefan Kircher and Prof. Dr. Peter Schopfer from the Institute of Biology II at the University of Freiburg have demonstrated that light is an environmental factor that controls the new development of lateral roots in plant root systems. Light modulates the pulsation frequency of the periodic activation of genes in the root tips using a so-called molecular oscillating system. In this process, the plant hormone auxin acts as a metronome that sets the frequency of the oscillations. The two scientists have published their research in the scientific journal Development.

Plants develop lateral roots that sprout from the parent roots in a regular pattern to form a root system that absorbs water and minerals from the ground. Scientists have known for some time that the plant hormone auxin plays an important role in the development of new root organs. However, the molecular mechanism responsible for the frequency and placement of the lateral roots along the parent root has been the source of much controversy. Kircher and Schopfer have now demonstrated that light plays a central role in this process. Depending on its intensity, light modulates both the periodic initiation of the initial gene activation pattern that determines where lateral roots will later develop, as well as the various stages of growth – up to the sprouting of lateral roots from the parent root. Based on these findings and in accordance with data from other research groups, the biologists from the University of Freiburg developed a molecular functional model of a biological clock driven by auxin. The more light the root is exposed to, the more auxin builds up and the faster the clock runs, thereby increasing the frequency of the initiation of lateral roots per unit of time. According to the researchers, this model represents a new kind of biological clock with an adjustable frequency that could also be used in developmental processes beyond the plant world.

This research study is part of a project called The Development and Light Regulation of Lateral Roots in Arabidopsis Seedlings, funded by the Deutsche Forschungsgemeinschaft (DFG).

Original Publication:
Kircher, S. and P. Schopfer (2018): The plant hormone auxin beats the time for oscillating light-regulated lateral root induction. Development (2018) 145: dev169839. DOI: 10. 1242/dev. 169839