LATERAL ORGAN BOUNDARIES DOMAIN transcription factors direct callus formation in Arabidopsis regeneration

Cell Res. 2012 Jul;22(7):1169-80. doi: 10.1038/cr.2012.63. Epub 2012 Apr 17.


The remarkable regeneration capability of plant tissues or organs under culture conditions has underlain an extensive practice for decades. The initial step in plant in vitro regeneration often involves the induction of a pluripotent cell mass termed callus, which is driven by the phytohormone auxin and occurs via a root development pathway. However, the key molecules governing callus formation remain unknown. Here we demonstrate that Arabidopsis LATERAL ORGAN BOUNDARIES DOMAIN (LBD)/ASYMMETRIC LEAVES2-LIKE (ASL) transcription factors are involved in the control of callus formation program. The four LBD genes downstream of AUXIN RESPONSE FACTORs (ARFs), LBD16, LBD17, LBD18 and LBD29, are rapidly and dramatically induced by callus-inducing medium (CIM) in multiple organs. Ectopic expression of each of the four LBD genes in Arabidopsis is sufficient to trigger spontaneous callus formation without exogenous phytohormones, whereas suppression of LBD function inhibits the callus formation induced by CIM. Moreover, the callus triggered by LBD resembles that induced by CIM by characteristics of ectopically activated root meristem genes and efficient regeneration capacity. These findings define LBD transcription factors as key regulators in the callus induction process, thereby establishing a molecular link between auxin signaling and the plant regeneration program.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Gene Expression Regulation, Plant / genetics
  • Gene Expression Regulation, Plant / physiology
  • Indoleacetic Acids / metabolism
  • Reproduction / genetics
  • Reproduction / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • Arabidopsis Proteins
  • Indoleacetic Acids
  • LBD16 protein, Arabidopsis
  • LBD18 protein, Arabidopsis
  • Transcription Factors