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A voltage‐dependent Ca 2+ homeostat operates in the plant vacuolar membrane
Author(s) -
Dindas Julian,
Dreyer Ingo,
Huang Shouguang,
Hedrich Rainer,
Roelfsema M. Rob G.
Publication year - 2021
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.17272
Subject(s) - cytosol , microbiology and biotechnology , homeostasis , membrane , biophysics , membrane potential , depolarization , biology , calcium signaling , vacuole , calcium , chemistry , biochemistry , signal transduction , cytoplasm , organic chemistry , enzyme
Summary Cytosolic calcium signals are evoked by a large variety of biotic and abiotic stimuli and play an important role in cellular and long distance signalling in plants. While the function of the plasma membrane in cytosolic Ca 2+ signalling has been intensively studied, the role of the vacuolar membrane remains elusive. A newly developed vacuolar voltage clamp technique was used in combination with live‐cell imaging, to study the role of the vacuolar membrane in Ca 2+ and pH homeostasis of bulging root hair cells of Arabidopsis. Depolarisation of the vacuolar membrane caused a rapid increase in the Ca 2+ concentration and alkalised the cytosol, while hyperpolarisation led to the opposite responses. The relationship between the vacuolar membrane potential, the cytosolic pH and Ca 2+ concentration suggests that a vacuolar H + /Ca 2+ exchange mechanism plays a central role in cytosolic Ca 2+ homeostasis. Mathematical modelling further suggests that the voltage‐dependent vacuolar Ca 2+ homeostat could contribute to calcium signalling when coupled to a recently discovered K + channel‐dependent module for electrical excitability of the vacuolar membrane.