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 (<i>ATG8</i>) 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 <i>ATG8</i> genes and function nonredundantly in this process. Disrupting the PLT-<i>ATG8</i> regulatory axis severely impairs organelle turnover, resulting in increased intracellular stress and ectopic accumulation of reactive oxygen species (ROS). PLT-<i>ATG8</i> 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.