Arabidopsis KANADI1 acts as a transcriptional repressor by interacting with a specific cis-element and regulates auxin biosynthesis, transport, and signaling in opposition to HD-ZIPIII factors

Plant Cell. 2014 Jan;26(1):246-62. doi: 10.1105/tpc.113.111526. Epub 2014 Jan 24.


The formation of leaves and other lateral organs in plants depends on the proper specification of adaxial-abaxial (upper-lower) polarity. KANADI1 (KAN1), a member of the GARP family of transcription factors, is a key regulator of abaxial identity, leaf growth, and meristem formation in Arabidopsis thaliana. Here, we demonstrate that the Myb-like domain in KAN1 binds the 6-bp motif GNATA(A/T) and that this motif alone is sufficient to squelch transcription of a linked reporter in vivo. In addition, we report that KAN1 acts as a transcriptional repressor. Among its targets are genes involved in auxin biosynthesis, auxin transport, and auxin response. Furthermore, we find that the adaxializing HD-ZIPIII transcription factor REVOLUTA has opposing effects on multiple components of the auxin pathway. We hypothesize that HD-ZIPIII and KANADI transcription factors pattern auxin accumulation and responsiveness in the embryo. Specifically, we propose the opposing actions of KANADI and HD-ZIPIII factors on cotyledon formation (KANADI represses and HD-ZIPIII promotes cotyledon formation) occur through their opposing actions on genes acting at multiple steps in the auxin pathway.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism
  • Arabidopsis Proteins / physiology*
  • Biological Transport
  • Gene Expression Regulation, Plant
  • Gene Regulatory Networks
  • Homeodomain Proteins / metabolism
  • Homeodomain Proteins / physiology*
  • Indoleacetic Acids / metabolism*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism
  • Repressor Proteins / physiology*
  • Signal Transduction / genetics
  • Transcription Factors


  • Arabidopsis Proteins
  • HD-Zip protein, Arabidopsis
  • Homeodomain Proteins
  • Indoleacetic Acids
  • KANADI protein, Arabidopsis
  • Repressor Proteins
  • Transcription Factors