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Title: Altered stomatal dynamics in ascorbate oxidase over-expressing tobacco plants suggest a role for dehydroascorbate signalling
Authors: Fotopoulos, Vasileios 
De Tullio, Mario C. 
Barnes, Jeremy 
Kanellis, Angelos K. 
Keywords: ABA;Apoplast;Ascorbic acid;Ascorbate oxidase;Dehydroascorbic acid (DHA);Hydrogen peroxide;Nicotiana tabacum L.;cv. Xanthi;Stomata;Transgenic plants;Water stress
Category: AGRICULTURAL SCIENCES;Agricultural Biotechnology;Other Agricultural Sciences
Field: Agricultural Sciences
Issue Date: Mar-2008
Source: Journal of Experimental Botany,Volume 59, Issue 4, March 2008, Pages 729-737
Journal: Journal of Experimental Botany 
Abstract: Control of stomatal aperture is of paramount importance for plant adaptation to the surrounding environment. Here, we report on several parameters related to stomatal dynamics and performance in transgenic tobacco plants (Nicotiana tabacum L., cv. Xanthi) over-expressing cucumber ascorbate oxidase (AO), a cell wall-localized enzyme of uncertain biological function that oxidizes ascorbic acid (AA) to monodehydroascorbic acid which dismutates yielding AA and dehydroascorbic acid (DHA). In comparison to WT plants, leaves of AO over-expressing plants exhibited reduced stomatal conductance (due to partial stomatal closure), higher water content, and reduced rates of water loss on detachment. Transgenic plants also exhibited elevated levels of hydrogen peroxide and a decline in hydrogen peroxide-scavenging enzyme activity. Leaf ABA content was also higher in AO over-expressing plants. Treatment of epidermal strips with either 1 mM DHA or 100 µM hydrogen peroxide resulted in rapid stomatal closure in WT plants, but not in AO-over-expressing plants. This suggests that signal perception and/or transduction associated with stomatal closure is altered by AO over-expression. These data support a specific role for cell wall-localized AA in the perception of environmental cues, and suggest that DHA acts as a regulator of stomatal dynamics.
Description: This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
ISSN: 14602431
DOI: doi:10.1093/jxb/erm359
Rights: © 2008 The Author(s).
Type: Article
Appears in Collections:Άρθρα/Articles

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