期刊
PLANT PHYSIOLOGY
卷 148, 期 2, 页码 796-807出版社
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.108.124248
关键词
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资金
- U.S. Department of Agriculture/Agricultural Research Service [58-62650-6001]
- National Science Foundation(NSF) [0344350, 020977, IBN-0209792, IBN-0209788, DBI-0400580]
- U.S. Department of Agriculture/Cooperative State Research, Education, and Extension Service [005-34402-17121]
- Direct For Biological Sciences
- Div Of Molecular and Cellular Bioscience [0344350] Funding Source: National Science Foundation
Potassium (K+) homeostasis is essential for diverse cellular processes, although how various cation transporters collaborate to maintain a suitable K+ required for growth and development is poorly understood. The Arabidopsis (Arabidopsis thaliana) genome contains numerous cation: proton antiporters (CHX), which may mediate K+ transport; however, the vast majority of these transporters remain uncharacterized. Here, we show that AtCHX13 (At2g30240) has a role in K+ acquisition. AtCHX13 suppressed the sensitivity of yeast (Saccharomyces cerevisiae) mutant cells defective in K+ uptake. Uptake experiments using Rb-86(+) as a tracer for K+ demonstrated that AtCHX13 mediated high-affinity K+ uptake in yeast and in plant cells with a K-m of 136 and 196 mu M, respectively. Functional green fluorescent protein-tagged versions localized to the plasma membrane of both yeast and plant. Seedlings of null chx13 mutants were sensitive to K+ deficiency conditions, whereas overexpression of AtCHX13 reduced the sensitivity to K+ deficiency. Collectively, these results suggest that AtCHX13 mediates relatively high-affinity K+ uptake, although the mode of transport is unclear at present. AtCHX13 expression is induced in roots during K+-deficient conditions. These results indicate that one role of AtCHX13 is to promote K+ uptake into plants when K+ is limiting in the environment.
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