Dissection of the ozone-induced calcium signature.
The cellular responses of plants to numerous extracellular stimuli are mediated by transient elevations in the concentration of cytosolic free calcium ([Ca2+]cyt). We have addressed the question of how cells can use this apparently ubiquitous system to initiate so many specific and appropriate end responses. We show that the pollutant gas ozone elicits a biphasic Ca2+ response in intact Arabidopsis plants and a subsequent increase in expression of the gene encoding the antioxidant defence enzyme glutathione-S-transferase (GST). The second of the two [Ca2+]cyt peaks, but not the first, could be eliminated either by pre-treatment of plants with lanthanum chloride, or by reducing the duration of ozone fumigation. Under these conditions, ozone-induced GST expression was abolished. These data provide a functional dissection of the ozone Ca2+ signalling pathway and indicate that the second ozone-induced [Ca2+]cyt peak provides the necessary information to direct expression of GST.
Clayton
H
H
Department of Biological Sciences, University of Lancaster, UK.
Knight
M R
MR
Knight
H
H
McAinsh
M R
MR
Hetherington
A M
AM
D017360:Arabidopsis / Q000201:enzymology / Q000378:metabolism; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism*; D017931:DNA Primers; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D010126:Ozone / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics
D017931:DNA Primers; D012333:RNA, Messenger; D010126:Ozone; D005982:Glutathione Transferase; D002118:Calcium