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Spatial variation in H2O2 response of Arabidopsis thaliana root epidermal Ca2+ flux and plasma membrane Ca2+ channels


Demidchik, V and Shabala, SN and Davies, JM, Spatial variation in H2O2 response of Arabidopsis thaliana root epidermal Ca2+ flux and plasma membrane Ca2+ channels, The Plant Journal, 49, (3) pp. 377-386. ISSN 0960-7412 (2007) [Refereed Article]

DOI: doi:10.1111/j.1365-313X.2006.02971.x


Hydrogen peroxide is an important regulatory agent in plants. This study demonstrates that exogenous H2O2 application to Arabidopsis thaliana root epidermis results in dose-dependent transient increases in net Ca2+ influx. The magnitude and duration of the transients were greater in the elongation zone than in the mature epidermis. In both regions, treatment with the cation channel blocker Gd3+ prevented H2O2-induced net Ca2+ influx, consistent with application of exogenous H2O2 resulting in the activation of plasma membrane Gd3+-sensitive Ca2+-influx pathways. Application of 10 mm H2O2 to the external plasma membrane face of elongation zone epidermal protoplasts resulted in the appearance of a hyperpolarization-activated Ca2+-permeable conductance. This conductance differed from that previously characterized as being responsive to extracellular hydroxyl radicals. In contrast, in mature epidermal protoplasts a plasma membrane hyperpolarization-activated Ca2+-permeable channel was activated only when H2O2 was present at the intracellular membrane face. Channel open probability increased with intracellular [H2O2] and at hyperpolarized voltages. Unitary conductance decreased thus: Ba2+ > Ca2+ (14.5 pS) > Mg2+ > Zn2+ (20 mm external cation, 1 mm H2O2). Lanthanides and Zn2+ (but not TEA+) suppressed the open probability without affecting current amplitude. The results suggest spatial heterogeneity and differential sensitivity of Ca2+ channel activation by reactive oxygen species in the root that could underpin signalling.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Shabala, SN (Professor Sergey Shabala)
ID Code:48790
Year Published:2007
Web of Science® Times Cited:167
Deposited By:Agricultural Science
Deposited On:2007-08-01
Last Modified:2014-02-03

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