Understanding lateral root formation, one cell at a time

Formation of lateral roots shapes the architecture of plant root systems and contributes to their fitness. In Arabidopsis, lateral roots follow a well-described sequence of events that lead to the emergence of a new root complete with its own meristem and a set of tissue and cell types very similar to the ones found in the primary root. How are the different cell types established? In a recent study, Serrano-Ron et al. (2021) used single-cell RNA sequencing (scRNA-seq) to profile the diversity of cell types in the forming lateral roots and revealed a hitherto unknown role for camalexins in controlling lateral root patterning.