Engineering root development with high precision.

Root development is controlled by dynamic interactions between gene regulation, hormonal signalling, developmental history and environmental inputs, creating multiple layers of control that can be harnessed for engineering. Recent advances in single-cell technologies, spatial transcriptomics and synthetic biology are beginning to resolve root development at the cellular level and enable increasingly precise manipulation of developmental programmes. Here, we discuss how lineage tracing, genetic recording of developmental history, cell-type-specific engineering and programmable genetic circuits can be integrated to understand and control root architecture. We highlight emerging strategies for engineering adaptive and context-dependent developmental behaviours, including history-dependent and reversible response programmes and rewired root-environment interactions. Together, these approaches establish a foundation for programmable and adaptive root system engineering in plants.