Type-B response regulators ARR1 and ARR12 regulate expression of AtHKT1;1 and accumulation of sodium in Arabidopsis shoots

Plant J. 2010 Dec;64(5):753-63. doi: 10.1111/j.1365-313X.2010.04366.x. Epub 2010 Oct 26.


Soil salinity affects a large proportion of the land worldwide, forcing plants to evolve a number of mechanisms to cope with salt stress. Cytokinin plays a role in the plant response to salt stress, but little is known about the mechanism by which cytokinin controls this process. We used a molecular genetics approach to examine the influence of cytokinin on sodium accumulation and salt sensitivity in Arabidopsis thaliana. Cytokinin application was found to increase sodium accumulation in the shoots of Arabidopsis, but had no significant affect on the sodium content in the roots. Consistent with this, altered sodium accumulation phenotypes were observed in mutants of each gene class of the cytokinin signal transduction pathway, including receptors, phospho-transfer proteins, and type-A and type-B response regulators. Expression of the gene encoding Arabidopsis high-affinity K(+) transporter 1;1 (AtHKT1;1), a gene responsible for removing sodium ions from the root xylem, was repressed by cytokinin treatment, but showed significantly elevated expression in the cytokinin response double mutant arr1-3 arr12-1. Our data suggest that cytokinin, acting through the transcription factors ARR1 and ARR12, regulates sodium accumulation in the shoots by controlling the expression of AtHKT1;1 in the roots.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism*
  • Cytokinins / pharmacology*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Expression Regulation, Plant
  • Mutation
  • Plant Roots / metabolism
  • Plant Shoots / metabolism*
  • RNA, Plant / genetics
  • Sodium / pharmacokinetics*
  • Sodium Chloride / pharmacology
  • Symporters / genetics
  • Symporters / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*


  • ARR1 protein, Arabidopsis
  • ARR12 protein, Arabidopsis
  • Arabidopsis Proteins
  • Cation Transport Proteins
  • Cytokinins
  • DNA-Binding Proteins
  • HKT1 protein, Arabidopsis
  • RNA, Plant
  • Symporters
  • Transcription Factors
  • Sodium Chloride
  • Sodium