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Overexpression of the potassium channel TPK b in small vacuoles confers osmotic and drought tolerance to rice
Author(s) -
Ahmad Izhar,
Devonshire Jean,
Mohamed Radwa,
Schultze Michael,
Maathuis Frans J. M.
Publication year - 2016
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13708
Subject(s) - vacuole , potassium , cytoplasm , biology , potassium channel , shoot , osmotic shock , microbiology and biotechnology , botany , biophysics , biochemistry , chemistry , gene , organic chemistry
Summary Potassium (K + ) is the most important cationic nutrient for all living organisms. Vacuolar two‐pore K + ( TPK ) channels are important players in the regulation of cellular levels of K + but have not been characterised in rice. In order to assess the role of Os TPK b, a K + selective ion channel predominantly expressed in the tonoplast of small vacuoles, we generated overexpressing ( OX ) lines using a constitutive promoter and compared their phenotypes with control plants. Relative to control plants, OX lines showed better growth when exposed to low‐K + or water stress conditions. K + uptake was greater in OX lines which may be driven by increased AKT 1 and HAK 1 activity. The enhanced K + uptake led to tissue K + levels that were raised in roots and shoots. Furthermore, energy dispersive X‐ray ( EDX ) analyses showed a higher cytoplasm: vacuole K + ratio which is likely to contribute to the increased stress tolerance. In all, the data suggest that TPK b can alter the K + status of small vacuoles, which is important for general cellular K + homeostasis which, in turn, affects stress tolerance.