title: Arabidopsis mutants reveal multiple singlet oxygen signaling pathways involved in stress response and development.
abstract: Shortly after the release of singlet oxygen ((1)O(2)) in chloroplasts drastic changes in nuclear gene expression occur in the conditional flu mutant of Arabidopsis that reveal a rapid transfer of signals from the plastid to the nucleus. Factors involved in this retrograde signaling were identified by mutagenizing a transgenic flu line expressing a (1)O(2)-responsive reporter gene. The reporter gene consisted of the luciferase open reading frame and the promoter of an AAA-ATPase gene (At3g28580) that was selectively activated by (1)O(2) but not by superoxide or hydrogen peroxide. A total of eight second-site mutants were identified that either constitutively activate the reporter gene and the endogenous AAA-ATPase irrespectively of whether (1)O(2) was generated or not (constitutive activators of AAA-ATPase, caa) or abrogated the (1)O(2)-dependent up-regulation of these genes as seen in the transgenic parental flu line (non-activators of AAA-ATPase, naa). The characterization of the mutants strongly suggests that (1)O(2)-signaling does not operate as an isolated linear pathway but rather forms an integral part of a signaling network that is modified by other signaling routes and impacts not only stress responses of plants but also their development.
authors.affiliation: Institute of Plant Sciences, ETH Zurich, Universitätstrasse 2, Zurich, Switzerland.
authors.forename: Aiswarya
authors.initials: A
authors.lastname: Baruah
authors.forename: Klára
authors.initials: K
authors.lastname: Simková
authors.forename: Klaus
authors.initials: K
authors.lastname: Apel
authors.forename: Christophe
authors.initials: C
authors.lastname: Laloi
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D000251:Adenosine Triphosphatases / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D016877:Oxidants / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012395:Rose Bengal / Q000494:pharmacology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D026082:Singlet Oxygen / Q000378:metabolism*
chemical_list: D016877:Oxidants; D011993:Recombinant Fusion Proteins; D026082:Singlet Oxygen; D012395:Rose Bengal; D006861:Hydrogen Peroxide; D008156:Luciferases; D000251:Adenosine Triphosphatases