In Ectocarpus, cylindrical cells are produced at the apex of the filament, from the apical cell elongation and divisions. After a few days, the resulting sub-apical cells start getting rounder, and ultimately become spherical. This corresponds to what we call the "rounding process" in Ectocarpus.
Using WT and cell rounding mutants, we are identifying the factors by which these cells change their shape. We track possible modifications of the mechanical properties of the cell wall, of the organisation of the cytoskeleton, of the turgor and other factors (gene expression, metabolic activity) which could account for this cell shape transition.
Illustration: Early increase in the number of round cells in the mutant étoile (Le Bail et al., Plant Cell 2011)
Main team contributors: Bénédicte Charrier, Elodie Rolland
Current collaborations: Benjamin Bailleul (IBPC, Paris); Denis Saint-Marcoux & Jane Langdale (Plant Dept, Univ Oxford, U-K).