How a non-cell autonomous compass orients cell division in plants

In multicellular organisms, cell division not only drives the separation of the mother cell into daughter cells but also dictates the organization of the cells in a tissue, their identities, and functions.

In walled organisms such as plants, the division plane's position irreversibly defines tissue topology and is tightly controlled.

While the importance of division plane orientation for tissue topology is uncontested, research on division plane positioning primarily focuses on cell-autonomous cues. It has been hypothesized that tissue-scale mechanical stress may influence division plane orientation.

Still, it needs to be clarified how such clues, let alone local tissue topology, are integrated into division plane positioning.

Here, I will tackle this fundamental knowledge gap by integrating the cell division process in a multicellular context and considering cell division as a non-cell autonomous mechanism, relying on cues from the local environment.

I propose a radical change of view where integrated mechanical (and possibly other) information at tricellular junctions provides a positional hallmark to guide division.

This hypothesis stems from preliminary data in my team that further identified the actin cytoskeleton as a central actor in the perception/processing of mechanical cues, thereby locally integrating tissue topology to orient division.

Using a combined approach of cell biology, genetics, and mechanical modeling at multiscale, we will investigate how plant cells orient their division by integrating biophysical and biochemical signals from surrounding tissues. In particular, we will address: How the dividing cell integrates the local neighborhood to orient the division plane?

What are the molecular cues incorporating the mechanical and geometrical features to instruct cell division? What is the role of the cell division orientation at the organ scale? This work will allow me to build a mechanistic, multiscale vision of plant cell division positioning.