title: Singlet oxygen signatures are detected independent of light or chloroplasts in response to multiple stresses.
abstract: The production of singlet oxygen is typically associated with inefficient dissipation of photosynthetic energy or can arise from light reactions as a result of accumulation of chlorophyll precursors as observed in fluorescent (flu)-like mutants. Such photodynamic production of singlet oxygen is thought to be involved in stress signaling and programmed cell death. Here we show that transcriptomes of multiple stresses, whether from light or dark treatments, were correlated with the transcriptome of the flu mutant. A core gene set of 118 genes, common to singlet oxygen, biotic and abiotic stresses was defined and confirmed to be activated photodynamically by the photosensitizer Rose Bengal. In addition, induction of the core gene set by abiotic and biotic selected stresses was shown to occur in the dark and in nonphotosynthetic tissue. Furthermore, when subjected to various biotic and abiotic stresses in the dark, the singlet oxygen-specific probe Singlet Oxygen Sensor Green detected rapid production of singlet oxygen in the Arabidopsis (Arabidopsis thaliana) root. Subcellular localization of Singlet Oxygen Sensor Green fluorescence showed its accumulation in mitochondria, peroxisomes, and the nucleus, suggesting several compartments as the possible origins or targets for singlet oxygen. Collectively, the results show that singlet oxygen can be produced by multiple stress pathways and can emanate from compartments other than the chloroplast in a light-independent manner. The results imply that the role of singlet oxygen in plant stress regulation and response is more ubiquitous than previously thought.
authors.affiliation: Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Avishai
authors.initials: A
authors.lastname: Mor
authors.forename: Eugene
authors.initials: E
authors.lastname: Koh
authors.forename: Lev
authors.initials: L
authors.lastname: Weiner
authors.forename: Shilo
authors.initials: S
authors.lastname: Rosenwasser
authors.forename: Hadas
authors.initials: H
authors.lastname: Sibony-Benyamini
authors.forename: Robert
authors.initials: R
authors.lastname: Fluhr
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects*; D003624:Darkness; D004578:Electron Spin Resonance Spectroscopy; D005408:Flagellin / Q000494:pharmacology; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D017343:Genes, Plant; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012402:Rotenone / Q000494:pharmacology; D026082:Singlet Oxygen / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects*; D059467:Transcriptome / Q000235:genetics
chemical_list: D012333:RNA, Messenger; D012402:Rotenone; D005408:Flagellin; D026082:Singlet Oxygen