The K+/H+ antiporter LeNHX2 increases salt tolerance by improving K+ homeostasis in transgenic tomato.
Plant Cell Environ
; 36(12): 2135-49, 2013 Dec.
Article
em En
| MEDLINE
| ID: mdl-23550888
ABSTRACT
The endosomal LeNHX2 ion transporter exchanges H(+) with K(+) and, to lesser extent, Na(+) . Here, we investigated the response to NaCl supply and K(+) deprivation in transgenic tomato (Solanum lycopersicum L.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K(+) the opposite was found. Analysis of mineral composition showed a higher K(+) content in roots, shoots and xylem sap of transgenic plants and no differences in Na(+) content between transgenic and untransformed plants grown either in the presence or the absence of 120 mm NaCl. Transgenic plants showed higher Na(+)/H(+) and, above all, K(+)/H(+) transport activity in root intracellular membrane vesicles. Under K(+) limiting conditions, transgenic plants enhanced root expression of the high-affinity K(+) uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K(+) depletion rates and half cytosolic K(+) activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K(+) and lower cytosolic K(+) activity than untransformed plants. These results indicate the fundamental role of K(+) homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
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Potássio
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Antiporters
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Solanum lycopersicum
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Tolerância ao Sal
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article