Deborah Bühler (Julius-Maximilians-Universität Würzburg)
Deborah Bühler's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Julius-Maximilians-Universität Würzburg in the year 2025 with the title:
Light-dependent activity control of Arabidopsis energy sensing kinase SnRK1
Sudden darkness triggers an almost immediate activation of the energy manager SnRK1, uncovering how plants dynamically safeguard energy homeostasis through photosynthesis-linked signaling.
The SnRK1 (SNF1-related protein kinase 1) is a key player in energy sensing and homeostasis in Arabidopsis thaliana. We observed that SnRK1 kinase activity is subject to regulation by diurnal cycles, exhibiting a rapid response to sudden fluctuations in light availability. The phosphorylation state of a SnRK1 reporter substrate was monitored, revealing that upon unexpected night (light off), SnRK1 activity is initiated within a few minutes. In search for the molecular players that govern SnRK1 activity we identified two key factors: CO2 availability and light intensity. Thus, the photosynthetic status rather than photoreceptor signaling seems to control the SnRK1 kinase. It is noteworthy that the regulation of SnRK1 by CO2 or light is characterised by a binary response, exhibiting a clear dichotomy between active and inactive states. This work opens new perspectives for further elucidating the integrative mechanisms underlying this response. Future work involving chloroplast retrograde signaling shall provide insights into the SnRK1 controlled mechanisms of energy homeostasis that allow plants to cope with ever changing environmental fluctuations.
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Deborah Bühler conducted this work at the Chair of Molecular Plant Physiology and Biophysics in the working group of Prof. Dr. Dirk Becker, in collaboration with Prof. Dr. Wolfgang Dröge-Laser (Chair of Pharmaceutical Biology).
