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TsHKT1;2, a HKT1 Homolog from the Extremophile Arabidopsis Relative Thellungiella salsuginea, Shows K+ Specificity in the Presence of NaC1.
- Source :
- Plant Physiology; Mar2012, Vol. 158 Issue 3, p1463-1474, 12p
- Publication Year :
- 2012
-
Abstract
- Cellular Na<superscript>+</superscript>/K<superscript>+</superscript> ratio is a crucial parameter determining plant salilxity stress resistance. We tested the function of plasma membrane Na<superscript>+</superscript>/K<superscript>+</superscript> cotransporters in the High-affinity K<superscript>+</superscript> Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thelhmgiella salsuginea. T. salsuginea contains at least two HKT genes. TsHKT1;1 is expressed at very low levels, while the abundant TsHKT1;2 is transcriptionally strongly up-regulated by salt stress. TsHKT-based RNA interference in T. salsuginea resulted in Na<superscript>+</superscript> sensitivity and K<superscript>+</superscript> deficiency. The athktl mutant lines overexpressing TsHKT1;2 proved less sensitive to Na<superscript>+</superscript> and showed less K<superscript>+</superscript> deficiency than lines overexpressing AtHKT1. TsHKT1;2 ectopically expressed in yeast mutants lacking Na<superscript>+</superscript> or K<superscript>+</superscript> transporters revealed strong K<superscript>+</superscript> transporter activity and selectivity for K<superscript>+</superscript> over Na<superscript>+</superscript>. Altering two amino acid residues in TsHKT1;2 to mimic the AtHKT1 sequence resulted in enhanced sodium uptake and loss of the TsHKT1;2 intrinsic K<superscript>+</superscript> transporter activity. We consider the maintenance of K<superscript>+</superscript> uptake through TsHKT1;2 trader salt stress an important component supporting the halophytic lifestyle of T. salsuginea. [ABSTRACT FROM AUTHOR]
- Subjects :
- CELL membranes
ARABIDOPSIS thaliana
PLANT genes
AMINO acids
SODIUM
PLANT proteins
Subjects
Details
- Language :
- English
- ISSN :
- 00320889
- Volume :
- 158
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Plant Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 73955666
- Full Text :
- https://doi.org/10.1104/pp.111.193110