Pectin homogalacturonan nanofilament expansion drives morphogenesis in plant epidermal cells

Wavy walls built by nanofilaments In the model plant Arabidopsis , pavement cells fit together with the lobes and curves of jigsaw puzzle pieces. Such complex cell shapes, in plants, were generally thought to be driven by turgor pressure. Haas et al. now show that the extracellular cell wall can actively shape the cell it contains without relying on turgor pressure. Nanofilaments of pectin homogalacturonan in the cell wall shift between crystalline and anisotropic phases according to whether they are methylated. The shift in form drives changes in cell wall shape that stand independent of turgor pressure. Science , this issue p. 1003