Optogenetics in plants: PULSE enables targeted and reversible gene expression control in plants in the presence of ambient light. Photo: Leonie-Alexa Koch, Institute of Synthetic Biology, University of Düsseldorf
Optogenetics offers a powerful research toolset for biology. It allows researchers to study the behaviour of biological cells with the help of molecular switches, which activate specific sections of the genome in a targeted manner. Like this, cellular processes such as signalling and metabolism can be controlled using only light. Until now, optogenetic methods have found only little use in plant research, because the light that plants need to grow leads to unspecific activation of the optical switches. A research team around Prof. Dr. Matias Zurbriggen and Prof. Dr. Rüdiger Simon from the Cluster of Excellence CEPLAS at the Heinrich Heine University Düsseldorf and the signalling scientists Prof. Dr. Thomas Ott, Prof. Dr. Wilfried Weber and Prof. Dr. Jens Timmer from the Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies at the University of Freiburg, in cooperation with colleagues from the University of East Anglia-Norwich, now succeeded in developing an optogenetic switch that is customized for the use in plants. This tool, named ‘PULSE’ (Plant Usable Light-Switch Elements), is suitable for plants growing under normal day/night cycles, as the researchers report in the journal Nature Methods.
Many optogenetic publications are focused on cells in mammalian, yeast and bacterial systems. In the research of plants it is used less frequently. One reason for this bias is a lack of suitable optical switches that can be used in plant cells and specifically controlled there, as the plants themselves require light to grow. PULSE avoids this problem, by being activated through targeted illumination with red light, while it is deactivated again by ambient white light.
PULSE has two optogenetic switches that respond to two different wavelengths. Monochromatic red light activates the switch, allowing a certain gene to be expressed at that precise moment. Blue light from daylight resets the switch, thus stopping gene expression. This process can be repeated any number of times.
“From now on, this genetic tool will also open up the unique possibility in plants to specifically switch on and off the activity of individual genes in only a few cells within an intact tissue,” Thomas Ott from CIBSS summarizes the study. “This enables us to investigate the function of individual genes in the living organism much more precisely.”
Rocio Ochoa-Fernandez, Nikolaj B. Abel, Franz-Georg Wieland, Jenia Schlegel, Leonie A. Koch, J. Benjamin Miller, Raphael Engesser, Giovanni Giuriani, Simon M. Brandl, Jens Timmer, Wilfried Weber, Thomas Ott, Rüdiger Simon, Matias D. Zurbriggen, Optogenetic control of gene expression in plants in the presence of ambient white light, Nature Methods (published online 29.06.2020). DOI: 10.1038/s41592-020-0868-y