From one cell to many: Morphogenetic field of lateral root founder cells in Arabidopsis is built by gradual recruitment (PNAS)

Because plant cells don’t usually move within an organ, it is possible to trace the developmental program cell by cell, through a technique called clonal analysis. If a single cell can be labeled in some heritable way, then all its progeny will also carry this label. Torres-Martínez et al. randomly induced expression of YPF in individual cells to investigate lateral root development in Arabidopsis. Lateral roots initiate from xylem-adjacent cells of the pericycle, and lateral root numbers vary depending on environmental conditions. The authors found that in most cases a single pericycle cell initiates the process of lateral root development and serves as the “founder cell”. Through an auxin-dependent process, the initial founder cell swiftly recruits adjacent cells also to become founder cells and contribute to the formation of the nascent lateral root, forming what is described as a morphogenetic field. The authors also note the distinction between founder cells, with progeny that all become part of the new lateral root, and stem cells, in which at least one of the progeny retains the original cell identity. (Summary by Mary Williams @PlantTeaching)  Proc. Natl. Acad. Sci. USA 10.1073/pnas.2006387117