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Abscisic acid induces oscillations in guard-cell cytosolic free calcium that involve phosphoinositide-specific phospholipase C.

Staxen, I. and Pical, C. and Montgomery, L. T. and Gray, J. E. and Hetherington, Alistair M. and McAinsh, Martin (1999) Abscisic acid induces oscillations in guard-cell cytosolic free calcium that involve phosphoinositide-specific phospholipase C. Proceedings of the National Academy of Sciences, 96 (4). pp. 1779-1784. ISSN 0027-8424

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Abstract

Oscillations in cytosolic free Ca2+ concentration ([Ca2+]cyt) are an important component of Ca2+-based signal transduction pathways. This fact has led us to investigate whether oscillations in [Ca2+]cyt are involved in the response of stomatal guard cells to the plant hormone abscisic acid (ABA). We show that ABA induces oscillations in guard-cell [Ca2+]cyt. The pattern of the oscillations depended on the ABA concentration and correlated with the final stomatal aperture. We examined the mechanism by which ABA generates oscillations in guard-cell [Ca2+]cyt by using 1-(6-{[17-3-methoxyestra-1,3,5(10)-trien-17-yl]amino}hexyl)-1H-pyrrole-2,5-dione (U-73122), an inhibitor of phosphoinositide-specific phospholipase C (PI-PLC)-dependent processes in animals. U-73122 inhibited the hydrolysis of phosphatidylinositol 4,5-bisphosphate by a recombinant PI-PLC, isolated from a guard-cell-enriched cDNA library, in a dose-dependent manner. This result confirms that U-73122 is an inhibitor of plant PI-PLC activity. U-73122 inhibited both ABA-induced oscillations in [Ca2+]cyt and stomatal closure. In contrast, U-73122 did not inhibit external Ca2+-induced oscillations in guard-cell [Ca2+]cyt and stomatal closure. Furthermore, there was no effect of the inactive analogue 1-(6-{[17-3-methoxyestra-1,3,5(10)-trien-17-yl]amino}hexyl)-2,5-pyrrolidinedione on recombinant PI-PLC activity or ABA-induced and external Ca2+-induced oscillations in [Ca2+]cyt and stomatal closure. This lack of effect suggests that the effects of U-73122 in guard cells are the result of inhibition of PI-PLC and not a consequence of nonspecific effects. Taken together, our data suggest a role for PI-PLC in the generation of ABA-induced oscillations in [Ca2+]cyt and point toward the involvement of oscillations in [Ca2+]cyt in the maintenance of stomatal aperture by ABA.

Item Type: Article
Journal or Publication Title: Proceedings of the National Academy of Sciences
Subjects: Q Science > QH Natural history > QH301 Biology
Departments: Faculty of Science and Technology > Lancaster Environment Centre
Faculty of Science and Technology > Engineering
ID Code: 8985
Deposited By: Dr Martin R McAinsh
Deposited On: 20 May 2008 11:32
Refereed?: Yes
Published?: Published
Last Modified: 01 Oct 2013 10:57
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/8985

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