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Plant Molecular Biology

, Volume 87, Issue 3, pp 317–327 | Cite as

The wheat NHX antiporter gene TaNHX2 confers salt tolerance in transgenic alfalfa by increasing the retention capacity of intracellular potassium

  • Yan-Min Zhang
  • Hong-Mei Zhang
  • Zi-Hui Liu
  • Hui-Cong Li
  • Xiu-Lin Guo
  • Guo-Liang Li
Article

Abstract

Previous studies have shown that TaNHX2 transgenic alfalfa (Medicago sativa L.) accumulated more K+ and less Na+ in leaves than did the wild-type plants. To investigate whether the increased K+ accumulation in transgenic plants is attributed to TaNHX2 gene expression and whether the compartmentalization of Na+ into vacuoles or the intracellular compartmentalization of potassium is the critical mechanism for TaNHX2-dependent salt tolerance in transgenic alfalfa, aerated hydroponic culture was performed under three different stress conditions: control condition (0.1 mM Na+ and 6 mM K+ inside culture solution), K+-sufficient salt stress (100 mM NaCl and 6 mM K+) and K+-insufficient salt stress (100 mM NaCl and 0.1 mM K+). The transgenic alfalfa plants had lower K+ efflux through specific K+ channels and higher K+ absorption through high-affinity K+ transporters than did the wild-type plants. Therefore, the transgenic plants had greater K+ contents and [K+]/[Na+] ratios in leaf tissue and cell sap. The intracellular compartmentalization of potassium is critical for TaNHX2-induced salt tolerance in transgenic alfalfa.

Keywords

NHX protein Na+/H+ antiporter Potassium Transgenic alfalfa Salt tolerance 

Abbreviations

ATPase

Adenosine triphosphatase

PPase

Pyrophosphatase

TEA

Tetraethylammonium chloride

NEM

N-ethyl maleimide

Notes

Acknowledgments

This work was supported by the Natural Science Foundation of Hebei Province, China (Grant No. C2013301033) and National Major Project for Transgenic Crops of Chinese Agriculture Ministry (Grant No. 2014ZX0800402B).

Supplementary material

11103_2014_278_MOESM1_ESM.doc (207 kb)
Supplementary material 1 (DOC 207 kb)

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Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  • Yan-Min Zhang
    • 1
  • Hong-Mei Zhang
    • 1
  • Zi-Hui Liu
    • 1
  • Hui-Cong Li
    • 1
  • Xiu-Lin Guo
    • 1
  • Guo-Liang Li
    • 1
  1. 1.Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry SciencesPlant Genetic Engineering Center of Hebei ProvinceShijiazhuangChina

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