Characterization of AtCHX17, a member of the cation/H+ exchangers, CHX family, from Arabidopsis thaliana suggests a role in K+ homeostasis
Article first published online: 27 JUL 2004
The Plant Journal
Volume 39, Issue 6, pages 834–846, September 2004
How to Cite
Cellier, F., Conéjéro, G., Ricaud, L., Luu, D. T., Lepetit, M., Gosti, F. and Casse, F. (2004), Characterization of AtCHX17, a member of the cation/H+ exchangers, CHX family, from Arabidopsis thaliana suggests a role in K+ homeostasis. The Plant Journal, 39: 834–846. doi: 10.1111/j.1365-313X.2004.02177.x
- Issue published online: 30 JUL 2004
- Article first published online: 27 JUL 2004
- Received 10 May 2004; accepted 15 June 2004.
- salt stress;
- Na+,K+/H+ antiporters;
- K+ transport;
- CHX transporters
The Arabidopsis genome contains many sequences annotated as encoding H+-coupled cotransporters. Among those are the members of the cation:proton antiporter-2 (CPA2) family (or CHX family), predicted to encode Na+,K+/H+ antiporters. AtCHX17, a member of the CPA2 family, was selected for expression studies, and phenotypic analysis of knockout mutants was performed. AtCHX17 expression was only detected in roots. The gene was strongly induced by salt stress, potassium starvation, abscisic acid (ABA) and external acidic pH. Using the β-glucuronidase reporter gene strategy and in situ RT-PCR experiments, we have found that AtCHX17 was expressed preferentially in epidermal and cortical cells of the mature root zones. Knockout mutants accumulated less K+ in roots in response to salt stress and potassium starvation compared with the wild type. These data support the hypothesis that AtCHX17 is involved in K+ acquisition and homeostasis.