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Reference Detail
| Reference | ||
|---|---|---|
| Author | Horie,T., Yoshida,K., Nakayama,H., Yamada,K., Oiki,S. and Shinmyo,A. | |
| Title | Two types of HKT transporters with different properties of Na+ and K+ transport in Oryza sativa | |
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Abstract: It is thought that Na+ and K+ homeostasis is crucial for salt-tolerance in plants. To better understand the Na+ and K+ homeostasis in important crop rice (Oryza sativa L.), a cDNA homologous to the wheat HKT1 encoding K+-Na+ symporter was isolated from japonica rice, cv Nipponbare (Ni-OsHKT1). We also isolated two cDNAs homologous to Ni-OsHKT1 from salt-tolerant indica rice, cv Pokkali (Po-OsHKT1, Po-OsHKT2). The predicted amino acid sequence of Ni-OsHKT1 shares 100% identity with Po-OsHKT1 and 91% identity with Po-OsHKT2, and they are 66-67% identical to wheat HKT1. Low-K+ conditions (less than 3 mM) induced the expression of all three OsHKT genes in roots, but mRNA accumulation was inhibited by the presence of 30 mM Na+. We further characterized the ion-transport properties of OsHKT1 and OsHKT2 using an expression system in the heterologous cells, yeast and Xenopus oocytes. OsHKT2 was capable of completely rescuing a K+-uptake deficiency mutation in yeast, whereas OsHKT1 was not under K+-limiting conditions. When OsHKTs were expressed in Na+-sensitive yeast, OsHKT1 rendered the cells more Na+-sensitive than did OsHKT2 in high NaCl conditions. The electrophysiological experiments for OsHKT1 expressed in Xenopus oocytes revealed that external Na+, but not K+, shifted the reversal potential toward depolarization. In contrast, for OsHKT2 either Na+ or K+ in the external solution shifted the reversal potential toward depolarization under the mixed Na+ and K+ containing solutions. These results suggest that two isoforms of HKT transporters, a Na+ transporter (OsHKT1) and a Na+- and K+-coupled transporter (OsHKT2), may act harmoniously in the salt tolerant indica rice. |
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| Journal | Plant J. | |
| Country | Japan | |
| Volume | 27(2) | |
| Pages | 129-138 | |
| Year | 2001 | |
| PubMed ID | 11489190 | |
| PubMed Central ID | - | |
| DOI | 10.1046/j.1365-313X.2001.01077.x | |
| URL | - | |
| Relation | ||
| Gene | HKT1 HKT2 | |
| INSD | AB061311 AB061312 AB061313 | |
| Strain | Wild Core Collection | - |
| Induced Mutation Lines(NIG Collection) | - | |
| Sterile Seed Strain | - | |
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Lethal Embryo Mutantion Strain |
- | |
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Stages in Each Organ - Muant Lines (Gene) |
- | |
| Cultivated Varieties(NIG Collection) | - | |
| Stages in Each Organ | - | |
