PLETHORA–autophagy axis activates organ regeneration through ROS modulation

Abstract

Injury-induced disruption of cellular homeostasis leads to accumulation of stress at sites adjacent to a wound. How do these cells mitigate wound-induced stress and restore cellular homeostasis to promote regeneration? To address this question, we examined the role of autophagy—a conserved quality control pathway that recycles defective cellular components to sustain cellular homeostasis—in facilitating wound repair in plants. We demonstrate that transcriptional activation of autophagy-related gene 8 (ATG8) genes is essential for de novo root regeneration, but dispensable for wound induced callus formation from an excised leaf. Plant-specific transcription factors PLETHORA (PLT) activate the transcription of a subset of ATG8 genes and function nonredundantly in this process. Disrupting the PLT–ATG8 regulatory axis severely impairs organelle turnover, resulting in increased intracellular stress and ectopic accumulation of reactive oxygen species (ROS). PLT–ATG8 mediated positioning of optimal ROS levels promotes the expression of stem-cell regulators for successful de novo root regeneration. Altogether, our findings illustrate how plants utilize kingdom-specific developmental regulators, such as PLTs, to activate evolutionarily conserved pathways, effectively managing wound-induced cellular stress and facilitating organ regeneration.