Spatial organisation of cell expansion by the cytoskeleton

The shape of plants is determined by the sum of cell division and cell growth. The cytoskeleton plays an important role in both processes. This thesis presents research that pinpoints how the cytoskeleton controls plant cell growth. Root hairs of the model plant Arabidopsis have been used as a model system. Their high growth speed makes it easy to detect changes in the location where growth takes place and the direction of growth. In this thesis, data are presented that demonstrate that the cytoskeleton of actin filaments determines where growth takes place and that microtubules, the other important component of the cytoskeleton, the direction of growth. Hypotheses, obtained by root hair research, have been tested on intercalary growing cells, where growth takes place over the whole cell surface. These experiments demonstrate that growth in the tested types of plant cells and other organisms (yeast) is regulated by the actin cytoskeleton in a similar way as in root hairs.