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TsHKT1;2, a HKT1 Homolog from the Extremophile Arabidopsis Relative Thellungiella salsuginea, Shows K+ Specificity in the Presence of NaCl1[C][W]

Authors :
Ali, Zahir
Park, Hyeong Cheol
Ali, Akhtar
Oh, Dong-Ha
Aman, Rashid
Kropornicka, Anna
Hong, Hyewon
Choi, Wonkyun
Chung, Woo Sik
Kim, Woe-Yeon
Bressan, Ray A.
Bohnert, Hans J.
Lee, Sang Yeol
Yun, Dae-Jin
Publication Year :
2012
Publisher :
American Society of Plant Biologists, 2012.

Abstract

Cellular Na(+)/K(+) ratio is a crucial parameter determining plant salinity stress resistance. We tested the function of plasma membrane Na(+)/K(+) cotransporters in the High-affinity K(+) Transporter (HKT) family from the halophytic Arabidopsis (Arabidopsis thaliana) relative Thellungiella 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(+) sensitivity and K(+) deficiency. The athkt1 mutant lines overexpressing TsHKT1;2 proved less sensitive to Na(+) and showed less K(+) deficiency than lines overexpressing AtHKT1. TsHKT1;2 ectopically expressed in yeast mutants lacking Na(+) or K(+) transporters revealed strong K(+) transporter activity and selectivity for K(+) over Na(+). 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(+) transporter activity. We consider the maintenance of K(+) uptake through TsHKT1;2 under salt stress an important component supporting the halophytic lifestyle of T. salsuginea.

Details

Language :
English
Database :
OpenAIRE
Accession number :
edsair.pmid..........fb6f2388e3b75d6fb253df5558e1cb6d