Roots are essential organs for higher plants. They provide the plant with nutrients and water, anchor the plant in the soil, and can serve as energy storage organs. One remarkable feature of roots is that they are able to adjust their growth to changing environments. This adjustment is possible through mechanisms that modulate a diverse set of root traits such as growth rate, diameter, growth direction and lateral root formation. The basis of these traits and their modulation are at the cellular level, where a multitude of genes and gene networks precisely regulate development in time and space and tune it to environmental conditions.
Slovak et al. describe the root system and review key studies that elucidated basic principles and pathways underlying the regulation of its growth and development. They further illustrate how systems biology has helped to address the complexity of these processes. Finally, they argue for pursuing systems genetics approaches which merge genetics, genomics, systems biology and phenomics to move beyond the limitations of past and current approaches.