, Volume 233, Issue 1, pp 189–200

An Arabidopsis senescence-associated protein SAG29 regulates cell viability under high salinity

  • Pil Joon Seo
  • Jung-Min Park
  • Seok Ki Kang
  • Sang-Gyu Kim
  • Chung-Mo Park
Original Article

DOI: 10.1007/s00425-010-1293-8

Cite this article as:
Seo, P.J., Park, JM., Kang, S.K. et al. Planta (2011) 233: 189. doi:10.1007/s00425-010-1293-8


The plasma membrane is an important cellular organ that perceives incoming developmental and environmental signals and integrates these signals into cellular regulatory mechanisms. It also acts as a barrier against unfavorable extracellular factors to maintain cell viability. Despite its importance for cell viability, molecular components determining cell viability and underlying mechanisms are largely unknown. Here, we show that a plasma membrane-localized MtN3 protein SAG29 regulates cell viability under high salinity in Arabidopsis. The SAG29 gene is expressed primarily in senescing plant tissues. It is induced by osmotic stresses via an abscisic acid-dependent pathway. Whereas the SAG29-overexpressing transgenic plants (35S:SAG29) exhibited an accelerated senescence and were hypersensitive to salt stress, the SAG29-deficient mutants were less sensitive to high salinity. Consistent with this, the 35S:SAG29 transgenic plants showed reduced cell viability in the roots under normal growth condition. In contrast, cell viability in the SAG29-deficient mutant roots was indistinguishable from that in the roots of control plants. Notably, the mutant roots exhibited enhanced cell viability under high salinity. Our observations indicate that the senescence-associated SAG29 protein is associated with cell viability under high salinity and other osmotic stress conditions. We propose that the SAG29 protein may serve as a molecular link that integrates environmental stress responses into senescing process.


ArabidopsisCell viabilityMtN3Salt stressSenescence



Abscisic acid


Cauliflower Mosaic Virus


Differential interference contrast microscopy


Fluorescein diacetate


Green fluorescent protein


Indole-3-acetic acid


Jasmonic acid


Murashige and Skoog


Propidium iodide


Quantitative real-time RT-PCR


Senescence-associated gene


Transmembrane motif

Supplementary material

425_2010_1293_MOESM1_ESM.pdf (373 kb)
Supplementary material 1 (PDF 372 kb)

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Pil Joon Seo
    • 1
  • Jung-Min Park
    • 1
  • Seok Ki Kang
    • 1
  • Sang-Gyu Kim
    • 2
  • Chung-Mo Park
    • 1
    • 3
  1. 1.Department of ChemistrySeoul National UniversitySeoulKorea
  2. 2.Department of Molecular EcologyMax Planck Institute for Chemical EcologyJenaGermany
  3. 3.Plant Genomics and Breeding InstituteSeoul National UniversitySeoulKorea