The establishment of a pre-pattern or competence to form new organs is a key feature of the postembryonic plasticity of plant development, and the elaboration of such pre-patterns leads to remarkable heterogeneity in plant form. In root systems, many of the differences in architecture can be directly attributed to the outgrowth of lateral roots. In recent years, efforts have focused on understanding how the pattern of lateral roots is established. Here, we review recent findings that point to a periodic mechanism for establishing this pattern, as well as roles for plant hormones, particularly auxin, in the earliest steps leading up to lateral root primordium development. In addition, we compare the development of lateral root primordia with in vitro plant regeneration and discuss possible common molecular mechanisms.
Funding
In the lab of P.N.B. this work was funded by grants from the Defense Advanced Research Projects Agency, National Institutes of Health, Howard Hughes Medical Institute, National Science Foundation and Gordon and Betty Moore Foundation. Work in the lab of T.B. was in part financed by grants of the Interuniversity Attraction Poles Programme from the Belgian Federal Science Policy Office; and W.X. is supported by a China Scholarship Council and a UGent BOF (Special Research Fund) cofounding grant. Deposited in PMC for release after 12 months.
