An NH4+-sensitive component dominates high-affinity K+ uptake in tomato plants
High-affinity K+ uptake has been studied in tomato plants grown under different conditions. K+ starvation induced a high-affinity K+ uptake with a Km of 10.5 ± 1.1 μM. This system was inhibited by the presence of NH4+ in the uptake solution and the inhibition was similar for plants grown in the abse...
| Autores: | , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2007 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/17510 |
| Acceso en línea: | http://hdl.handle.net/10261/17510 |
| Access Level: | acceso abierto |
| Palabra clave: | Potassium Ammonium Sodium Salinity High-affinity Tomato |
| Sumario: | High-affinity K+ uptake has been studied in tomato plants grown under different conditions. K+ starvation induced a high-affinity K+ uptake with a Km of 10.5 ± 1.1 μM. This system was inhibited by the presence of NH4+ in the uptake solution and the inhibition was similar for plants grown in the absence or in the presence of NH4+. High-affinity K+ uptake was inhibited in plants grown in the presence of NaCl without NH4+ but not in plants grown with NaCl and with NH4+. A full-length cDNA has been isolated that probably encodes a high-affinity K+ uptake system, LeHAK5. The gene encoding LeHAK5 is induced in K+-starved plants and the presence of NH4+ in the growth solution further increases LeHAK5 expression. In K+-starved plants grown with NaCl in the absence of NH4+ LeHAK5 expression is almost abolished but when plants are grown with NaCl in the presence of NH4+ a strong expression of the gene is detected. The LeHAK5 expression pattern parallels the presence of high-affinity K+ uptake in tomato plants which suggests that this gene is encoding an important component of K+ uptake in the micromolar range of K+ concentrations. |
|---|