, Volume 221, Issue 2, pp 212–221 | Cite as

Rice K+ uptake channel OsAKT1 is sensitive to salt stress

  • Ines Fuchs
  • Sonja Stölzle
  • Natalya Ivashikina
  • Rainer Hedrich
Original Article


Potassium ions constitute the most important macronutrients taken up by plants. To unravel the mechanisms of K+ uptake and its sensitivity to salt stress in the model plant rice, we isolated and functionally characterized OsAKT1, a potassium channel homologous to the Arabidopsis root inward rectifier AKT1. OsAKT1 transcripts were predominantly found in the coleoptile and in the roots of young rice seedlings. K+ channel mRNA decreases in response to salt stress, both in the shoot and in the root of 4-day-old rice seedlings. Following expression in HEK293 cells, we were able to characterize OsAKT1 as a voltage-dependent, inward-rectifying K+ channel regulated by extracellular Ca2+ and protons. Patch-clamp studies on rice root protoplasts identified a K+ inward rectifier with similar channel properties as heterologously expressed OsAKT1. In line with the transcriptional downregulation of OsAKT1 in response to salt stress, inward K+ currents were significantly reduced in root protoplasts. Thus, OsAKT1 seems to represent the dominant salt-sensitive K+ uptake channel in rice roots.


AKT1 K+ channel Plant nutrition Rice Salt stress 


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Ines Fuchs
    • 1
  • Sonja Stölzle
    • 1
    • 2
  • Natalya Ivashikina
    • 1
    • 3
  • Rainer Hedrich
    • 1
  1. 1.Department of Molecular Plant Physiology and BiophysicsUniversity of WürzburgWürzburgGermany
  2. 2.Nanion TechnologiesMunichGermany
  3. 3.All-Russian Research Institute of AgrochemistryMoscowRussia

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