Dr. Kasper van GelderenLight Signaling and Cell Biology

We investigate how plant light perception and signaling is organized in the cell nucleus. Plants create sugars from light energy, therefore, light perception and responses are essential for plant life. Plants have evolved photoreceptors to sense light (quality) and act upon it.

Phytochromes are the main red light sensors in plants and phytochromes form small (~500nm) subnuclear bodies, which also contain supporting cofactors and downstream transcription factors. These subnuclear structures are called photobodies and they play an important role in regulating light responses. Importantly, phytochromeB (phyB) is not only required for light-, but also for temperature-sensing, suggesting that photobodies also play an important role for plant responses to ambient temperature. Despite their importance, it remains unclear how the formation of photobodies aids phytochrome signaling, how output specificity is achieved in response to divergent stimuli and how this information influences plant developmental decisions. The formation of nuclear bodies is a general process in the eukaryotic nucleus, and lessons learned from photobodies may help us understand nuclear organization in general. To tackle these fundamental questions we investigate the formation and responses of photobodies to light and temperature using an integrated approach of high resolution live imaging and biochemistry.

Model of phyB photobody formation

Our current projects

- Live Imaging of phyB photobodies

   - How do photobodies react to the environment?
   - How is photobody composition changing under different conditions?
   - How does phyB activity affect photobodies?

- phyB photobody biochemistry

   - What are photobodies made of?
   - How does liquid-liquid phase-separation help shape photobodies?
   - which molecular components drive phase separation?

- Development and phyB photobodies

   - Unpick the relation between phyB photobody signaling and development.
   - Can we disturb photobodies with new molecular biology (optogenetic) tools?

live imaging setup controlling light and temperature at the confocal microscope