Premium
The characterization of differential calcium signalling in tobacco guard cells
Author(s) -
Wood Nicola T.,
Allan Andrew C.,
Haley Ann,
ViryMoussaïd Martine,
Trewavas Anthony J.
Publication year - 2000
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2000.00881.x
Subject(s) - guard cell , aequorin , egta , abscisic acid , microbiology and biotechnology , extracellular , signal transduction , chemistry , transduction (biophysics) , intracellular , biophysics , calcium , biology , biochemistry , organic chemistry , gene
Summary Two novel approaches for the study of Ca 2+ ‐mediated signal transduction in stomatal guard cells are described. Stimulus‐induced changes in guard‐cell cytosolic Ca 2+ ([Ca 2+ ] cyt ) were monitored using viable stomata in epidermal strips of a transgenic line of Nicotiana plumbaginifolia expressing aequorin (the proteinous luminescent reporter of Ca 2+ ) and in a new transgenic line in which aequorin expression was targeted specifically to the guard cells. The results indicated that abscisic acid (ABA)‐induced stomatal closure was accompanied by increases in [Ca 2+ ] cyt in epidermal strips. In addition to ABA, mechanical and low‐temperature signals directly affected stomatal behaviour, promoting rapid closure. Elevations of guard‐cell [Ca 2+ ] cyt play a key role in the transduction of all three stimuli. However, there were striking differences in the magnitude and kinetics of the three responses. Studies using Ca 2+ channel blockers and the Ca 2+ chelator EGTA further suggested that mechanical and ABA signals primarily mobilize Ca 2+ from intracellular store(s), whereas the influx of extracellular Ca 2+ is a key component in the transduction of low‐temperature signals. These results illustrate an aspect of Ca 2+ signalling whereby the specificity of the response is encoded by different spatial or kinetic Ca 2+ elevations.