Plant Molecular Biology

, Volume 51, Issue 1, pp 71–81

Salinity stress-tolerant and -sensitive rice (Oryza sativa L.) regulate AKT1-type potassium channel transcripts differently

  • Dortje Golldack
  • Francoise Quigley
  • Christine B. Michalowski
  • Uma R. Kamasani
  • Hans J. Bohnert
Article

Abstract

In the indica rice (Oryza sativa L.) a cDNA was characterized that encoded OsAKT1 homologous to inward-rectifying potassium channels of the AKT/KAT subfamily. Transcript analysis located OsAKT1 predominantly in roots with low abundance in leaves. Cell-specificity of OsAKT expression was analyzed by in situ hybridizations. In roots, strongest signals were localized to the epidermis and the endodermis, whereas lower transcript levels were detected in cells of the vasculature and the cortex. In leaves, expression was detected in xylem parenchyma, phloem, and mesophyll cells. Transcriptional regulation and cell specificity of OsAKT1 during salt stress was compared in rice lines showing different salinity tolerance. In the salt-tolerant, sodium-excluding varieties Pokkali and BK, OsAKT1 transcripts disappeared from the exodermis in plants treated with 150 mM NaCl for 48 h but OsAKT1 transcription was not repressed in these cells in the salt-sensitive, sodium-accumulating variety IR29. Significantly, all lines were able to maintain potassium levels under sodium stress conditions, while sodium concentrations in the leaves of IR29 increased 5–10-fold relative to the sodium concentration in BK or Pokkali. The divergent, line-dependent and salt-dependent, regulation of this channel does not significantly affect potassium homeostasis under salinity stress. Rather, repression in Pokkali/BK and lack of repression in IR29 correlate with the overall tolerance character of these lines.

in situ hybridization NaCl stress Oryza sativa potassium channel 

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Copyright information

© Kluwer Academic Publishers 2003

Authors and Affiliations

  • Dortje Golldack
    • 1
    • 2
  • Francoise Quigley
    • 1
    • 3
  • Christine B. Michalowski
    • 4
  • Uma R. Kamasani
    • 4
  • Hans J. Bohnert
    • 1
    • 5
    • 6
  1. 1.Germany
  2. 2.Lehrstuhl für Stoffwechselphysiologie und Biochemie der PflanzenUniversität BielefeldBielefeldGermany
  3. 3.Laboratoire de Genétique Moléculaire des Plantes, UMR CNRS 5575Université Joseph FourierGrenobleFrance
  4. 4.Department of BiochemistryUniversity of ArizonaTucsonUSA
  5. 5.Department of Plant SciencesUSA
  6. 6.Department of Molecular and Cellular BiologyUniversity of ArizonaTucsonUSA
  7. 7.Departments of Plant Biology and Crop SciencesUniversity of Illinois, ERML 196UrbanaUSA

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