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Abstract Detail


Oxidative Stress

Kim, Chanhong [1], Lee, Keunpyo [1], Landgraf, Frank [1], Apel, Klaus [1].

EXECUTER1- and EXECUTER2-dependent transfer of stress-related signals from the plastid to the nucleus of Arabidopsis thaliana.

Shortly after the release of singlet oxygen (1O2) within the plastid of the conditional flu mutant of Arabidopsis drastic changes in nuclear gene expression occur that reveal a rapid transfer of signals from the plastid to the nucleus. In contrast to retrograde control of nuclear gene expression by plastid signals described earlier the primary effect of 1O2 generation in the flu mutant is not the control of chloroplast biogenesis but the activation of a broad range of signaling pathways known to be involved in numerous biotic and abiotic stress responses. This novel and distinct activity of a plastid-derived signal suggests a new function of the chloroplast, namely that of a sensor of environmental changes that activates a broad range of stress responses. Inactivation of the plastid protein EXECUTER1 attenuates the extent of 1O2-induced upregulation of nuclear gene expression, but it does not fully eliminate these changes. A second related nuclear-encoded protein, dubbed EXECUTER2, has also been implicated with the signaling of 1O2-dependent nuclear gene expression changes. Like EXECUTER1, EXECUTER2 is confined to the plastid. In contrast to EXECUTER1, however, inactivation of EXECUTER2 further enhances the intensity of 1O2–mediated changes of nuclear gene expression. Inactivation of both EXECUTER proteins in the ex1/ex2/flu triple mutant is sufficient to suppress the up- and downregulation of almost all 1O2-responsive genes and to adjust their transcripts to the wild-type level. Retrograde control of 1O2-responsive genes seems to require the concerted action of both EXECUTER proteins within the plastid compartment


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Related Links:
The genetic basis of singlet oxygen-induced stress responses of Arabidopsis thaliana


1 - Swiss Federal Institute of Technology Zurich, Institute of Plant Sciences, Universitystrasse 2, Zurich, 8092, Switzerland

Keywords:
singlet oxygen retrograde signaling.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P06012
Abstract ID:590


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