Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-18969
Beyhl, D; Hörtensteiner, S; Martinoia, E; Farmer, EE; Fromm, J; Marten, I; Hedrich, R (2009). The fou2 mutation in the major vacuolar cation channel TPC1 confers tolerance to inhibitory luminal calcium. The Plant Journal, 58(5):715-723.
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Summary The SV channel encoded by the TPC1 gene represents a Ca(2+)- and voltage-dependent vacuolar cation channel. Point mutation D454N within TPC1, named fou2 for fatty acid oxygenation upregulated 2, results in increased synthesis of the stress hormone jasmonate. As wounding causes Ca(2+) signals and cytosolic Ca(2+) is required for SV channel function, we here studied the Ca(2+)-dependent properties of this major vacuolar cation channel with Arabidopsis thaliana mesophyll vacuoles. In patch clamp measurements, wild-type and fou2 SV channels did not exhibit differences in cytosolic Ca(2+) sensitivity and Ca(2+) impermeability. K(+) fluxes through wild-type TPC1 were reduced or even completely faded away when vacuolar Ca(2+) reached the 0.1-mm level. The fou2 protein under these conditions, however, remained active. Thus, D454N seems to be part of a luminal Ca(2+) recognition site. Thereby the SV channel mutant gains tolerance towards elevated luminal Ca(2+). A three-fold higher vacuolar Ca/K ratio in the fou2 mutant relative to wild-type plants seems to indicate that fou2 can accumulate higher levels of vacuolar Ca(2+) before SV channel activity vanishes and K(+) homeostasis is impaired. In response to wounding fou2 plants might thus elicit strong vacuole-derived cytosolic Ca(2+) signals resulting in overproduction of jasmonate.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute of Plant Biology|
|DDC:||580 Plants (Botany)|
|Date:||03 March 2009|
|Deposited On:||10 Jun 2009 16:26|
|Last Modified:||23 Nov 2012 16:22|
|Additional Information:||This is an electronic version of an Article published in The Plant Journal, Volume 58, Issue 5 (p 715-723)|
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