Plant Molecular Biology

, Volume 74, Issue 4, pp 367–380

The woody plant poplar has a functionally conserved salt overly sensitive pathway in response to salinity stress

  • Ren-Jie Tang
  • Hua Liu
  • Yan Bao
  • Qun-Dan Lv
  • Lei Yang
  • Hong-Xia Zhang
Article

DOI: 10.1007/s11103-010-9680-x

Cite this article as:
Tang, R., Liu, H., Bao, Y. et al. Plant Mol Biol (2010) 74: 367. doi:10.1007/s11103-010-9680-x

Abstract

In Arabidopsis thaliana, the salt overly sensitive (SOS) pathway plays an essential role in maintaining ion homeostasis and conferring salt tolerance. Here we identified three SOS components in the woody plant Populus trichocarpa, designated as PtSOS1, PtSOS2 and PtSOS3. These putative SOS genes exhibited an overlapping but distinct expression pattern in poplar plants and the transcript levels of SOS1 and SOS2 were responsive to salinity stress. In poplar mesophyll protoplasts, PtSOS1 was specifically localized in the plasma membrane, whereas PtSOS2 was distributed throughout the cell, and PtSOS3 was predominantly targeted to the plasma membrane. Heterologous expression of PtSOS1, PtSOS2 and PtSOS3 could rescue salt-sensitive phenotypes of the corresponding Arabidopsis sos mutants, demonstrating that the Populus SOS proteins are functional homologues of their Arabidopsis counterpart. In addition, PtSOS3 interacted with, and recruited PtSOS2 to the plasma membrane in yeast and in planta. Reconstitution of poplar SOS pathway in yeast cells revealed that PtSOS2 and PtSOS3 acted coordinately to activate PtSOS1. Moreover, expression of the constitutively activated form of PtSOS2 partially complemented the sos3 mutant but not sos1, suggesting that PtSOS2 functions genetically downstream of SOS3 and upstream of SOS1. These results indicate a strong functional conservation of SOS pathway responsible for salt stress signaling from herbaceous to woody plants.

Keywords

SOS pathwaySalt stressPopulusArabidopsisFunctional conservation

Supplementary material

11103_2010_9680_MOESM1_ESM.tif (3.5 mb)
Fig. S1 Protein sequence alignment of AtSOS1 and PtSOS1. The underlined putative transmembrane domains were predicted according to TMHMM2 program (http://www.cbs.dtu.dk/services/TMHMM/). (TIFF 3597 kb)
11103_2010_9680_MOESM2_ESM.tif (81 kb)
Fig. S2 Protein sequence alignment of AtSOS2 and PtSOS2. FISL motif was underlined. The star positions the point mutation made in this study. The amino acid threonine (T) 169 was mutated to aspirate (D) in the activation loop of PtSOS2. (TIFF 81 kb)
11103_2010_9680_MOESM3_ESM.tif (54 kb)
Fig. S3 Protein sequence alignment of AtSOS3 and PtSOS3. Four EF-hand motifs for calcium binding are underlined. (TIFF 53 kb)

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Ren-Jie Tang
    • 1
  • Hua Liu
    • 1
  • Yan Bao
    • 1
  • Qun-Dan Lv
    • 1
  • Lei Yang
    • 1
  • Hong-Xia Zhang
    • 1
  1. 1.National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina