ORIGINAL PAPER
Overexpression of the Na
+
/H
+
antiporter gene from Suaeda
salsa confers cold and salt tolerance to transgenic
Arabidopsis thaliana
Jinyao Li Æ Gangqiang Jiang Æ Ping Huang Æ
Ji Ma Æ Fuchun Zhang
Received: 26 January 2007 / Accepted: 21 May 2007 / Published online: 5 July 2007
Ó Springer Science+Business Media B.V. 2007
Abstract Na
+
/H
+
exchanger catalyzes the counter-
transport of Na
+
and H
+
across membranes. By using
reverse transcription PCR (RT-PCR) technique and
Rapid Amplification of cDNA Ends (RACE), a
Suaeda salsa cDNA clone was isolated and the
sequence contains 2133 bp with an open reading
frame of 1674 bp. The deduced amino acid sequence
is similar to that of AtNHX1 and NHE isoforms in
mammals, and shares high similarity with the
sequences within predicted transmembrane segments
and an amiloride-binding domain. In an attempt to
improve salt tolerance of Arabidopsis plants, an
expression vector containing SsNHX1 cDNA driven
by a cauliflower mosaic virus 35S promoter was
transferred into Arabidopsis plants. Transgenic plants
could normally grow and complete life cycle under
treatment with 200 mM NaCl but the wild-type
Arabidopsis plant growth were severely retarded.
Transgenic seedlings could resume and keep normal
growth after treatment at À78C for 5 h but wt plants
became hoariness and then all died.
Keywords Cold tolerance Á Na
+
/H
+
exchanger Á
Salt tolerance Á SsNHX1 Á Suaeda salsa
Abbreviations
NHX1 Vacuolar Na
+
/H
+
Exchanger
RACE Rapid Amplification of cDNA Ends
RT-PCR Reverse transriptase
polymerase chain reaction
WT Wildtype
Introduction
Soil salinity is a major limiting factor to produc-
tivity of crops. High salinity causes ion imbalance
and hyperosmotic stress in plants. The United
Nations Environment Program estimates that
approximately 20% of agricultural land and 50%
of cropland in the world is salt-stressed (Flowers
and Yeo 1995). Control of intracellular ion homeo-
stasis is essential for all cellular organisms. Many
antiporters were involved into this process. Trans-
porters such as HKT1 and LCT1 have been shown
to be permeable to Na
+
in oocytes and yeasts
(Rubio et al. 1995; Schachtman et al. 1997). A
screen of a T-DNA-tagged Arabidopsis (Col-0 gl1
The GenBank accession number for the SsNHX1 is AY
261806.
J. Li Á G. Jiang Á P. Huang Á J. Ma Á F. Zhang (&)
Key Laboratory of Molecular Biology,
Xinjiang Key Laboratory of Biological Resources
and Genetic Engineering, College of Life Science
and Technology, Xinjiang University,
14 Shengli Road,
Urumqi 830046, P. R. China
e-mail: zfcxju@xju.edu.cn
123
Plant Cell Tiss Organ Cult (2007) 90:41–48
DOI 10.1007/s11240-007-9246-z