Freddy C. Igiebor (Universität Heidelberg)
Freddy Can Igiebor's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Heidelberg University in the year 2025 with the title:
Biophysical and Transcriptional Dissection of Tissue-Specific Light Memory Functions in PhyB Photobodies
Freddy’s work is the first detailed study demonstrating that PhyB photobodies (Red and Far-red photoreceptors) function as light information storage modules in a tissue-specific manner, linking their liquid–liquid phase separation behavior with theoretical modeling, simulations, and transcriptional readouts in Arabidopsis thaliana.
Freddy Igiebor’s thesis investigates how PhyB photobodies, the red/far-red light photoreceptors in Arabidopsis thaliana, act as cellular memory units that store and process light information in a tissue-specific manner. This particular function has been hypothesized and identified in other eukaryotic phase-separated systems, but not in plant light perception. By precisely mapping the dynamics of PhyB photobodies through live confocal imaging and fluorescence recovery after photobleaching (FRAP) experiments, he determined the parameters that govern photobody stability. He then used these parameters to simulate a biophysical model of the process (in collaboration with the Graf group at EMBL), which showed a pattern closely resembling the photobody formation observed in super-resolution imaging. Finally, through single-nucleus RNA sequencing, he demonstrated that certain cell types exhibit differential transcriptional states linked to specific light conditions, potentially connecting them to memory function. This part of the work will be analyzed more extensively in the near future and will serve as the basis for a publication on Freddy’s thesis research. The results indicate that photobody formation and dissolution are not purely diffusion-driven but are actively regulated and history-dependent, with epidermal and mesophyll tissues exhibiting distinct memory capacities. These findings provide new insight into how plants encode environmental information through biophysical condensates, opening new perspectives for future optogenetic control of gene expression and light-based cellular engineering.
___
Freddy Can Igiebor conducted this work at Heidelberg University in collaboration with the European Molecular Biology Laboratory (EMBL) in the working group of Kasper Van Gelderen and Isabella Graf, respectively.
