title: Cyclopentenone isoprostanes induced by reactive oxygen species trigger defense gene activation and phytoalexin accumulation in plants.
abstract: Lipid peroxidation may be initiated either by lipoxygenases or by reactive oxygen species (ROS). Enzymatic oxidation of alpha-linolenate can result in the biosynthesis of cyclic oxylipins of the jasmonate type while free-radical-catalyzed oxidation of alpha-linolenate may yield several classes of cyclic oxylipins termed phytoprostanes in vivo. Previously, we have shown that one of these classes, the E1-phytoprostanes (PPE1), occurs ubiquitously in plants. In this work, it is shown that PPE1 are converted to novel cyclopentenone A1- and B1-phytoprostanes (PPA1 and PPB1) in planta. Enhanced formation of PPE1, PPA1, and PPB1 is observed after peroxide stress in tobacco cell cultures as well as after infection of tomato plants with a necrotrophic fungus, Botrytis cinerea. PPA1 and PPB1 display powerful biologic activities including activation of mitogen-activated protein kinase (MAPK) and induction of glutathione-S-transferase (GST), defense genes, and phytoalexins. Data collected so far infer that enhanced phytoprostane formation is a general consequence of oxidative stress in plants. We propose that phytoprostanes are components of an oxidant-injury-sensing, archaic signaling system that serves to induce several plant defense mechanisms.
authors.affiliation: Julius-von-Sachs-Institute of Biosciences, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz 2, Germany.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Thoma
authors.forename: Christiane
authors.initials: C
authors.lastname: Loeffler
authors.forename: Alok K
authors.initials: AK
authors.lastname: Sinha
authors.forename: Meetu
authors.initials: M
authors.lastname: Gupta
authors.forename: Markus
authors.initials: M
authors.lastname: Krischke
authors.forename: Bert
authors.initials: B
authors.lastname: Steffan
authors.forename: Thomas
authors.initials: T
authors.lastname: Roitsch
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Mueller
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology; D020171:Botrytis / Q000254:growth & development; D002478:Cells, Cultured; D003517:Cyclopentanes / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D018506:Gene Expression Regulation, Plant; D005982:Glutathione Transferase / Q000096:biosynthesis; D006026:Glycoside Hydrolases / Q000096:biosynthesis; D007113:Immunity, Innate / Q000235:genetics; D028421:Isoprostanes / Q000737:chemistry / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D015394:Molecular Structure; D054883:Oxylipins; D010545:Peroxides / Q000378:metabolism; D010650:Phenylalanine Ammonia-Lyase / Q000096:biosynthesis; D010936:Plant Extracts / Q000096:biosynthesis*; D010944:Plants / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012603:Scopoletin / Q000378:metabolism; D012717:Sesquiterpenes; D013729:Terpenes; D014026:Nicotiana / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D015533:Transcriptional Activation; D043324:beta-Fructofuranosidase; D000094162:Phytoalexins
chemical_list: D003517:Cyclopentanes; D028421:Isoprostanes; D054883:Oxylipins; D010545:Peroxides; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D012717:Sesquiterpenes; D013729:Terpenes; C011006:jasmonic acid; D005982:Glutathione Transferase; D020928:Mitogen-Activated Protein Kinases; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase; D010650:Phenylalanine Ammonia-Lyase; D012603:Scopoletin; D000094162:Phytoalexins