Abstract
De novo organ regeneration is the process in which adventitious roots or shoots regenerate from detached or wounded organs. De novo organ regeneration can occur either in natural conditions, e.g. adventitious root regeneration from the wounded sites of detached leaves or stems, or in in-vitro tissue culture, e.g. organ regeneration from callus. In this review, we summarize recent advances in research on the molecular mechanism of de novo organ regeneration, focusing on the role of the WUSCHEL-RELATED HOMEOBOX11 (WOX11) gene in the model plant Arabidopsis thaliana. WOX11 is a direct target of the auxin signaling pathway, and it is expressed in, and regulates the establishment of, the founder cell during de novo root regeneration and callus formation. WOX11 activates the expression of its target genes to initiate root and callus primordia. Therefore, WOX11 links upstream auxin signaling to downstream cell fate transition during regeneration. We also discuss the role of WOX11 in diverse species and its evolution in plants.