The high affinity K+ transporter AtHAK5 plays a physiological role in planta at very low K+ concentrations and provides a caesium uptake pathway in Arabidopsis
Caesium (Cs(+)) is a potentially toxic mineral element that is released into the environment and taken up by plants. Although Cs(+) is chemically similar to potassium (K(+)), and much is known about K(+) transport mechanisms, it is not clear through which K(+) transport mechanisms Cs(+) is taken up...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 59(2008), 3 vom: 09., Seite 595-607 |
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| Weitere Verfasser: | , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2008
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Arabidopsis Proteins Potassium Channels Potassium-Hydrogen Antiporters Quaternary Ammonium Compounds Symporters potassium transporter, Arabidopsis AKT1 protein, Arabidopsis mehr... |
| Zusammenfassung: | Caesium (Cs(+)) is a potentially toxic mineral element that is released into the environment and taken up by plants. Although Cs(+) is chemically similar to potassium (K(+)), and much is known about K(+) transport mechanisms, it is not clear through which K(+) transport mechanisms Cs(+) is taken up by plant roots. In this study, the role of AtHAK5 in high affinity K(+) and Cs(+) uptake was characterized. It is demonstrated that AtHAK5 is localized to the plasma membrane under conditions of K(+) deprivation, when it is expressed. Growth analysis showed that AtHAK5 plays a role during severe K(+) deprivation. Under K(+)-deficient conditions in the presence of Cs(+), Arabidopsis seedlings lacking AtHAK5 had increased inhibition of root growth and lower Cs(+) accumulation, and significantly higher leaf chlorophyll concentrations than wild type. These data indicate that, in addition to transporting K(+) in planta, AtHAK5 also transports Cs(+). Further experiments showed that AtHAK5 mediated Cs(+) uptake into yeast cells and that, although the K(+) deficiency-induced expression of AtHAK5 was inhibited by low concentrations of NH(4)(+) in planta, Cs(+) uptake by yeast was stimulated by low concentrations of NH(4)(+). Interestingly, the growth of the Arabidopsis atakt1-1 mutant was more sensitive to Cs(+) than the wild type. This may be explained, in part, by increased expression of AtHAK5 in the atakt1-1 mutant. It is concluded that AtHAK5 is a root plasma membrane uptake mechanism for K(+) and Cs(+) under conditions of low K(+) availability |
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| Beschreibung: | Date Completed 22.05.2008 Date Revised 20.11.2014 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1460-2431 |
| DOI: | 10.1093/jxb/erm330 |