Optimal levels of PLETHORA2 for root regeneration capacity (Cell Reports)

Plants can regenerate organs after damage, or even regenerate a whole plant. The regeneration efficiency is different across the organism. In this study, Durgaprasad et al. studied the factors that determine regeneration competence across Arabidopsis roots. They focussed on PLETHORA2 (PLT2), a gene involved in root stem cell maintenance that is expressed in a gradient in the roots. The authors made cuts at different positions in the roots and measured organ regeneration; through these resection experiments, they found a correlation between PLT2 expression levels and the regeneration potential along the root. This capacity is extended if PLT2 expression is modified. However, if the expression level of PLT2 exceeds a threshold, the regeneration capacity is reduced. Evidence suggests the action of a regulatory loop where PLT2 maintains the optimal level of PLT2 expression. It was recently found that PLT proteins form complexes; in the case of root regeneration, higher levels of PLT2 could modify the stoichiometry of protein complexes and affect the expression of target genes. (Summary by Humberto Herrera-Ubaldo) Cell Reports 10.1016/j.celrep.2019.08.099