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Changes in Expression Level of OsHKT1

Authors :
Nayef, Mohammad Al
Solis, Celymar
Shabala, Lana
Ogura, Takaaki
Chen, Zhonghua
Bose, Jayakumar
Maathuis, Frans J.M.
Venkataraman, Gayatri
Tanoi, Keitaro
Yu, Min
Zhou, Meixue
Horie, Tomoaki
Shabala, Sergey
Source :
International Journal of Molecular Sciences, Volume 21, Issue 14
Publication Year :
2020
Publisher :
Multidisciplinary Digital Publishing Institute, 2020.

Abstract

In rice, the OsHKT1<br />5 gene has been reported to be a critical determinant of salt tolerance. This gene is harbored by the SKC1 locus, and its role was attributed to Na+ unloading from the xylem. No direct evidence, however, was provided in previous studies. Also, the reported function of SKC1 on the loading and delivery of K+ to the shoot remains to be explained. In this work, we used an electrophysiological approach to compare the kinetics of Na+ uptake by root xylem parenchyma cells using wild type (WT) and NIL(SKC1) plants. Our data showed that Na+ reabsorption was observed in WT, but not NIL(SKC1) plants, thus questioning the functional role of HKT1<br />5 as a transporter operating in the direct Na+ removal from the xylem. Instead, changes in the expression level of HKT1<br />5 altered the activity of membrane transporters involved in K+ and Ca2+ acquisition and homeostasis in the rice epidermis and stele, explaining the observed phenotype. We conclude that the role of HKT1<br />5 in plant salinity tolerance cannot be attributed to merely reducing Na+ concentration in the xylem sap but triggers a complex feedback regulation of activities of other transporters involved in the maintenance of plant ionic homeostasis and signaling under stress conditions.

Details

Language :
English
ISSN :
14220067
Database :
OpenAIRE
Journal :
International Journal of Molecular Sciences
Accession number :
edsair.multidiscipl..b097b564e1332a0caf3eac3bc8b4d4c5
Full Text :
https://doi.org/10.3390/ijms21144882