Gradient Expression of Transcription Factor Imposes a Boundary on Organ Regeneration Potential in Plants

A wide variety of multicellular organisms across the kingdoms display remarkable ability to restore their tissues or organs when they suffer damage. However, the ability to repair damage is not uniformly distributed throughout body parts. Here, we unravel the elusive mechanistic basis of boundaries on organ regeneration potential using root tip resection as a model and show that the dosage of gradient-expressed PLT2 transcription factor is the underlying cause. While transient downregulation of PLT2 in distinct set of plt mutant backgrounds renders meristematic cells incapable of regeneration, forced expression of PLT2 acts through auto-activation to confer regeneration potential to the cells undergoing differentiation. Surprisingly, sustained exposure to nuclear PLT2, beyond a threshold, leads to reduction of regeneration potential despite giving rise to longer meristem. Our studies reveal dosage-dependent role of gradient-expressed PLT2 in root tip regeneration and uncouple the size of an organ from its regeneration potential. [Display omitted] •The developmental gradient of PLT2 correlates with organ regeneration competence•PLTs are essential for primary as well as lateral root tip regeneration•PLT2 confers regeneration potential to differentiating cells via auto-activation•The regeneration potential of root meristem can be decoupled from its size Durgaprasad et al. show that dosage of a gradient-expressed transcription factor orchestrates the regeneration competence in developing root tip. Interestingly, the regeneration potential of root meristem can be separated from its size.