Branco Weiss Fellow Since
2026
Research Category
Biophysics, Microscopy, Plant Cell Biology
Research Location
LP2N, IOGS, CNRS, Université de Bordeaux
Background
Plants have no brain and no nervous system, yet they grow, develop and defend themselves as tightly coordinated organisms. They achieve this by continuously exchanging molecular signals between neighbouring cells through plasmodesmata – nanometre-scale channels that cross the cell wall and link the interiors of adjacent cells into a living communication network. Electron microscopy has revealed the architecture of these channels in remarkable detail, but only as frozen snapshots. Scientists still have no way to watch molecules move through an individual channel in real time. As a result, some of the most basic questions remain open: how does transport differ from one channel to the next, how is it switched on and off, and how do plants rapidly rewire their cellular connectivity when faced with stress? Answering them requires measuring communication not as an average over thousands of channels at once, but one channel at a time.
Details of Research
Dr. Ronceray’s project, The Plant Wiretap, sets out to eavesdrop on this molecular conversation with single-channel resolution. He is building a dedicated optical microscope and imaging framework able to detect and localise single fluorescent molecules as they pass through individual plasmodesmata deep inside living Arabidopsis roots. Because neighbouring channels lie below the diffraction limit of light, telling them apart requires super-resolution microscopy, and capturing their rare, fast passage events further demands purpose-built optics, tailored molecular probes, and physics-based analysis of how molecules move under extreme confinement. By tracking these microscopic messages within intact tissue, the approach will map which channels are active, how often molecules cross, and how long each crossing takes – and then follow how this connectivity is reshaped by developmental cues and environmental stress. Ultimately, the work aims to make the molecular traffic through plasmodesmata directly measurable, turning it into a quantitative, real-time readout of plant physiology, and to shed light on how coordinated behaviour arises in a living system with no central controller.
