Glutathione deficiency of the Arabidopsis mutant pad2-1 affects oxidative stress-related events, defense gene expression, and the hypersensitive response

Dubreuil-Maurizi, Carole; Vitecek, Jan; Marty, Laurent; Branciard, Lorelise; Frettinger, Patrick; Wendehenne, David; Meyer, Andreas J.; Mauch, Felix; Poinssot, Benoît

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Glutathione deficiency of the Arabidopsis mutant pad2-1 affects oxidative stress-related events, defense gene expression, and the hypersensitive response

Dubreuil-Maurizi, Carole Université de Bourgogne, UMR Plante Microbe Environnement, Dijon, France
Vitecek, Jan Université de Bourgogne, UMR Plante Microbe Environnement, Dijon, France - Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic
Marty, Laurent Heidelberg Institute for Plant Science, Heidelberg University, Germany
Branciard, Lorelise Department of Biology, University of Fribourg, Switzerland
Frettinger, Patrick Université de Bourgogne, UMR Plante Microbe Environnement, Dijon, France
Wendehenne, David Université de Bourgogne, UMR Plante Microbe Environnement, Dijon, France
Meyer, Andreas J. Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, Czech Republic - Heidelberg Institute for Plant Science, Heidelberg University, Germany
Mauch, Felix Department of Biology, University of Fribourg, Switzerland
Poinssot, Benoît Université de Bourgogne, UMR Plante Microbe Environnement, Dijon, France

17.10.2011

Published in:

Plant Physiology. - 2011, vol. 157, no. 4, p. 2000-2012

English The Arabidopsis (Arabidopsis thaliana) phytoalexin-deficient mutant pad2-1 displays enhanced susceptibility to a broad range of pathogens and herbivorous insects that correlates with deficiencies in the production of camalexin, indole glucosinolates, and salicylic acid (SA). The pad2-1 mutation is localized in the GLUTAMATE-CYSTEINE LIGASE (GCL) gene encoding the first enzyme of glutathione biosynthesis. While pad2-1 glutathione deficiency is not caused by a decrease in GCL transcripts, analysis of GCL protein level revealed that pad2-1 plants contained only 48% of the wild-type protein amount. In contrast to the wild type, the oxidized form of GCL was dominant in pad2-1, suggesting a distinct redox environment. This finding was corroborated by the expression of GRX1-roGFP2, showing that the cytosolic glutathione redox potential was significantly less negative in pad2-1. Analysis of oxidative stress-related gene expression showed a higher transcript accumulation in pad2-1 of GLUTATHIONE REDUCTASE, GLUTATHIONE-S-TRANSFERASE, and RESPIRATORY BURST OXIDASE HOMOLOG D in response to the oomycete Phytophthora brassicae. Interestingly, oligogalacturonide elicitation in pad2-1 revealed a lower plasma membrane depolarization that was found to act upstream of an impaired hydrogen peroxide production. This impaired hydrogen peroxide production was also observed during pathogen infection and correlated with a reduced hypersensitive response in pad2-1. In addition, a lack of pathogen-triggered expression of the ISOCHORISMATE SYNTHASE1 gene, coding for the SA-biosynthetic enzyme isochorismate synthase, was identified as the cause of the SA deficiency in pad2-1. Together, our results indicate that the pad2-1 mutation is related to a decrease in GCL protein and that the resulting glutathione deficiency negatively affects important processes of disease resistance.

Faculty

Faculté des sciences et de médecine

Department

Département de Biologie

Language