A Functionally Conserved Regulatory Module Confers Universal Regeneration Potential to Plant Tissues in Response to Injury

Abstract

Plants can repair wounds throughout their body when they suffer injuries. The molecular mechanisms underlying this universal regeneration potential, and how regulation of tissue regeneration compares with its formation during development, remains unknown. Here, we reveal an essential role for members of the PLETHORA(PLT)/ AINTEGUMENTA(ANT) gene family in activating innate responses to injuries of the form that growing aerial parts of the plant naturally encounter. Strikingly, PLT act through the embryonic symmetry determinant CUP-SHAPED COTYLEDON2(CUC2) but not through root or shoot stem cell regulators in this process. Wound repair and vascular regeneration in damaged aerial organs growing in a normal developmental context were severely impaired in plt/ant mutant combinations as well as in cuc2 mutant. We find that the PLT-CUC2 module-dependent control of local hormonal environment and cell polarisation drives vascular regeneration in damaged aerial organs. We further provide several lines of evidence for PLT-CUC2 driven mechanism of wound repair and finally, rescue the regeneration defects by reconstituting endogenous local hormone production in the mutants. Interestingly, the necessity of PLT-CUC2 module specifically for vascular regeneration, but not vascular tissue development, distinguishes tissue’s ability to repair wound from its developmental program. This study reveals the essential mechanism of wound repair across the plant body and discerns the regulation of tissue regeneration from its formation during development.

Keywords: vascular regeneration in aerial organs, PLT-CUC2 module, wound repair in normal developmental context, local hormonal environment, natural regeneration in Arabidopsis, auxin