Cytoskeleton dynamics during lateral root initiation in Arabidopsis thaliana

Morphogenesis of lateral roots relies on the asymmetric cell division of initially symmetric founder cells. This division is preceded by the tightly controlled asymmetric radial expansion of these cells. The cellular mechanisms that license and ensure the coordination of these events are unknown. Here, we quantitatively analyse microtubule and F-actin dynamics during lateral root initiation. Using mutants, pharmacological and tissue-specific genetic perturbations, we show that dynamic reorganisation of both microtubule and F-actin networks is necessary for the asymmetric expansion of the founder cells. This cytoskeleton remodelling intertwines with auxin signalling in the pericycle and endodermis in order for founder cells to acquire a basic polarity required for initiating lateral root development.