Loss of the vacuolar cation channel, AtTPC1, does not impair Ca 2+ signals induced by abiotic and biotic stresses

Ranf S, Wünnenberg P, Lee J, Becker D, Dunkel M, Hedrich R, Scheel D, Dietrich P (2008)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2008

Journal

Plant Journal Wiley

Book Volume: 53

Pages Range: 287-299

Journal Issue: 2

DOI: 10.1111/j.1365-313X.2007.03342.x

Open Access Link: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-313X.2007.03342.x/abstract

Abstract

The putative two-pore Ca channel TPC1 has been suggested to be involved in responses to abiotic and biotic stresses. We show that AtTPC1 co-localizes with the K-selective channel AtTPK1 in the vacuolar membrane. Loss of AtTPC1 abolished Ca-activated slow vacuolar (SV) currents, which were increased in AtTPC1-over-expressing Arabidopsis compared to the wild-type. A Ca-insensitive vacuolar cation channel, as yet uncharacterized, could be resolved in tpc1-2 knockout plants. The kinetics of ABA- and CO-induced stomatal closure were similar in wild-type and tpc1-2 knockout plants, excluding a role of SV channels in guard-cell signalling in response to these physiological stimuli. ABA-, K-, and Ca -dependent root growth phenotypes were not changed in tpc1-2 compared to wild-type plants. Given the permeability of SV channels to mono- and divalent cations, the question arises as to whether TPC1 in vivo represents a pathway for Ca entry into the cytosol. Ca responses as measured in aequorin-expressing wild-type, tpc1-2 knockout and TPC1-over-expressing plants disprove a contribution of TPC1 to any of the stimulus-induced Ca signals tested, including abiotic stresses (cold, hyperosmotic, salt and oxidative), elevation in extracellular Ca concentration and biotic factors (elf18, flg22). In good agreement, stimulus- and Ca-dependent gene activation was not affected by alterations in TPC1 expression. Together with our finding that the loss of TPC1 did not change the activity of hyperpolarization-activated Ca -permeable channels in the plasma membrane, we conclude that TPC1, under physiological conditions, functions as a vacuolar cation channel without a major impact on cytosolic Ca homeostasis. © 2007 The Authors.

Authors with CRIS profile

Petra Dietrich Professur für Zellbiologie der Pflanzen

Involved external institutions

Leibniz Institute of Plant Biochemistry / Leibniz-Institut für Pflanzenbiochemie DE Germany (DE) Julius-Maximilians-Universität Würzburg DE Germany (DE)

How to cite

APA:

Ranf, S., Wünnenberg, P., Lee, J., Becker, D., Dunkel, M., Hedrich, R.,... Dietrich, P. (2008). Loss of the vacuolar cation channel, AtTPC1, does not impair Ca 2+ signals induced by abiotic and biotic stresses. Plant Journal, 53(2), 287-299. https://doi.org/10.1111/j.1365-313X.2007.03342.x

MLA:

Ranf, Stefanie, et al. "Loss of the vacuolar cation channel, AtTPC1, does not impair Ca 2+ signals induced by abiotic and biotic stresses." Plant Journal 53.2 (2008): 287-299.

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