TY - JOUR
T1 - Regulation of expression of the vacuolar Na+/H+ antiporter gene AtNHX1 by salt stress and abscisic acid
AU - Shi, Huazhong
AU - Zhu, Jian Kang
N1 - Funding Information:
This work was supported by US National Institutes of Health grant R01GM59138 to J.-K.Z. We thank Dr Eduardo Blumwald for helpful discussions.
PY - 2002/10
Y1 - 2002/10
N2 - The Arabidopsis thaliana AtNHX1 gene encodes a vacuolar Na+/H+ antiporter that is important in salt tolerance. We report here the tissue distribution and regulation of AtNHX1 expression by salt stress and abscisic acid (ABA). The steady-state level of AtNHX1 transcript was up-regulated by treatment with NaCl, KCl or ABA. AtNHX1 promoter-GUS analysis in transgenic Arabidopsis showed that AtNHX1 was expressed in all tissues except the root tip. Strong GUS expression was detected in guard cells, suggesting that AtNHX1 may play a role in pH regulation and/or K+ homeostasis in the specialized cells. AtNHX1 promoter activity was substantially up-regulated by NaCl, KCl or ABA, demonstrating that salt and ABA regulation of AtNHX1 expression occurs at the transcriptional level. Strong induction of GUS activity in root hair cells was observed, which suggests a role of AtNHX1 in storing Na+ in the enlarged vacuoles in root hair cells. The up-regulation of AtNHX1 transcript levels by NaCl was reduced in abi1-1, aba2-1 and aba3-1, but not in abi2-1, sos1, sos2 or sos3 mutants. ABA-induced AtNHX1 expression was also decreased in abi1-1 but not in abi2-1. These results suggest that salt stress up-regulates AtNHX1 expression transcriptionally and the up-regulation is partially dependent on ABA biosynthesis and ABA signaling through ABI1.
AB - The Arabidopsis thaliana AtNHX1 gene encodes a vacuolar Na+/H+ antiporter that is important in salt tolerance. We report here the tissue distribution and regulation of AtNHX1 expression by salt stress and abscisic acid (ABA). The steady-state level of AtNHX1 transcript was up-regulated by treatment with NaCl, KCl or ABA. AtNHX1 promoter-GUS analysis in transgenic Arabidopsis showed that AtNHX1 was expressed in all tissues except the root tip. Strong GUS expression was detected in guard cells, suggesting that AtNHX1 may play a role in pH regulation and/or K+ homeostasis in the specialized cells. AtNHX1 promoter activity was substantially up-regulated by NaCl, KCl or ABA, demonstrating that salt and ABA regulation of AtNHX1 expression occurs at the transcriptional level. Strong induction of GUS activity in root hair cells was observed, which suggests a role of AtNHX1 in storing Na+ in the enlarged vacuoles in root hair cells. The up-regulation of AtNHX1 transcript levels by NaCl was reduced in abi1-1, aba2-1 and aba3-1, but not in abi2-1, sos1, sos2 or sos3 mutants. ABA-induced AtNHX1 expression was also decreased in abi1-1 but not in abi2-1. These results suggest that salt stress up-regulates AtNHX1 expression transcriptionally and the up-regulation is partially dependent on ABA biosynthesis and ABA signaling through ABI1.
KW - Abscisic acid
KW - Na/H antiporter gene
KW - Salt tolerance
UR - http://www.scopus.com/inward/record.url?scp=0036791468&partnerID=8YFLogxK
U2 - 10.1023/A:1019859319617
DO - 10.1023/A:1019859319617
M3 - Article
C2 - 12369629
AN - SCOPUS:0036791468
SN - 0167-4412
VL - 50
SP - 543
EP - 550
JO - Plant molecular biology
JF - Plant molecular biology
IS - 3
ER -