EdU-Based Quantitative Analysis of Cell Proliferation in Arabidopsis Root Meristems

The division of a mother cell into two daughter cells is a fundamental process in biology, involving the transfer of genomic information to the next generation of cells. In plant roots, cell divisions occur in the root apical meristem, a specialized tissue located at the plant's root tip. Cell proliferation rates in the root apical meristem shape root growth, thereby contributing to general development as well as the acclimatization to stressful environmental conditions through phenotypic plasticity. Here, we present a protocol for the microscopical analysis of cell proliferation in Arabidopsis thaliana root meristems by 5-ethynyl-2'-deoxyuridine (EdU) staining. EdU, a thymine-analog, is incorporated into newly synthesized DNA of proliferative cells during the S-phase of the cell cycle. Subsequently, EdU-containing nuclei can be labeled with a fluorophore and detected by confocal laser scanning microscopy. The combination of the EdU assay with cell wall staining enables the quantification of root meristem architecture parameters and cell division activity from microscopic images. Together, this can elucidate how root meristems respond to changes in environmental conditions or address fundamental questions of developmental plant biology.