TRH1 encodes a potassium transporter required for tip growth in arabidopsis root hairs

S. Rigas, G. Debrosses, K. Haralampidis, F. Vicente-Agullo, K. A. Feldmann, A. Grabov, L. Dolan, P. Hatzopoulos

Research output: Contribution to journalArticlepeer-review

237 Scopus citations


Root hair initiation involves the formation of a bulge at the basal end of the trichoblast by localized diffuse growth. Tip growth occurs subsequently at this initiation site and is accompanied by the establishment of a polarized cytoplasmic organization. Arabidopsis plants homozygous for a complete loss-of-function tiny root hair 1 (trh1) mutation were generated by means of the T-DNA-tagging method. Trichoblasts of trh1 plants form initiation sites but fail to undergo tip growth. A predicted primary structure of TRH1 indicates that it belongs to the AtKT/AtKUP/HAK K+ transporter family. The proposed function of TRH1 as a K+ transporter was confirmed in 86Rb uptake experiments, which demonstrated that trh1 plants are partially impaired in K+ transport. In line with these results, TRH1 was able to complement the trk1 potassium transporter mutant of Saccharomyces, which is defective in high-affinity K+ uptake. Surprisingly, the trh1 phenotype was not restored when mutant seedlings were grown at high external potassium concentrations. These data demonstrate that TRH1 mediates K+ transport in Arabidopsis roots and is responsible for specific K+ translocation, which is essential for root hair elongation.

Original languageEnglish (US)
Pages (from-to)139-151
Number of pages13
JournalPlant Cell
Issue number1
StatePublished - 2001

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology


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