A hub for ABA signaling to the nucleus: significance of a cytosolic and nuclear dual-localized PPR protein SOAR1 acting downstream of Mg-chelatase H subunit

Plant Signal Behav. 2014;9(11):e972899. doi: 10.4161/15592316.2014.972899.


SOAR1 is a cytosol-nucleus dual-localized pentatricopeptide repeat (PPR) protein, which we indentified recently as a crucial regulator in the CHLH/ABAR (Mg-chelatase H subunit /putative ABA receptor)-mediated signaling pathway, acting downstream of CHLH/ABAR and upstream of a nuclear ABA-responsive bZIP transcription factor ABI5. Downregulation and upregulation of SOAR1 expression alter dramatically both ABA sensitivity and expression of a subset of key, nuclear ABA-responsive genes, suggesting that SOAR1 is a hub for ABA signaling to the nucleus, and CHLH/ABAR mediates a central signaling pathway to regulate downstream gene expression through SOAR1.

Keywords: ABA receptor; ABA signaling; ABA, abscisic acid; ABAR, putative ABA receptor; CHLH, Mg-chelatase H subunit; CPN20, cochaperonin 20; Mg-chelatase H subunit; PPR, pentatricopeptide repeat; SOAR1, suppressor of the ABAR-overexpressor 1; WRKY, WRKY-domain transcription factor; cytosol-nucleus dual-localization; pentatricopeptide repeat (PPR) protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Cell Nucleus / metabolism*
  • Cytosol / metabolism*
  • Lyases / metabolism*
  • Protein Subunits / metabolism
  • Protein Transport
  • Signal Transduction*


  • Arabidopsis Proteins
  • Protein Subunits
  • pentatricopeptide repeat protein, Arabidopsis
  • Abscisic Acid
  • Lyases
  • magnesium chelatase