Simkova, Klara , Baruah, Aiswarya , Laloi, Christophe , Apel, Klaus .
A genetic approach towards elucidating singlet oxygen-mediated signaling in Arabidopsis thaliana.
In plants and aerobic organisms reactive oxygen species (ROS) are continuously produced as byproducts of various metabolic pathways. Exposure to unfavorable environmental stress factors such as high light lead to an increase production of chemically distinct ROS primarily within the chloroplast that may act either as cytotoxic compounds or as signaling molecules.
The conditional flu mutant of Arabidopsis accumulates protochlorophyllide in the dark, which upon illumination acts as a photosensitizer and generates singlet oxygen (1O2) in the plastid compartment. Release of 1O2 in flu initiates two distinct stress responses, cell death and growth inhibition, which are attributable to the activation of a genetically determined stress response programs. In addition, rapid changes in expression of nuclear encoded genes in flu were observed which reflect an intense singlet oxygen-dependent chloroplast-to-nucleus communication.
A genetic approach based on the fusion of a singlet oxygen-inducible promoter of a gene encoding AAA ATPase to a luciferase reporter gene and a subsequent mutant screen has been used to study factors involved in the singlet oxygen-mediated signal transduction. Two groups of mutants were isolated: caa mutants (constitutive AAA ATPase expressor) showing constitutive high luciferase activity even under permissive conditions and naa mutants (non-expressors of AAA ATPase) that no longer show luciferase activity induction after the release of 1O2 in flu.
Comprehensive characterization and identification of mutated genes in both caa and naa mutants will allow us to unravel molecular basis of singlet oxygen-mediated signal transduction from the plastid to the nucleus that triggers stress responses of higher plants.
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1 - Institute of Plant Sciences, ETH Zürich, Plant Genetics, Universitätstrasse 2, Zürich, 8092, Switzerland
2 - Institute of Plant Sciences, ETH Zürich
reactive oxygen species
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM