title: Differential impact of lipoxygenase 2 and jasmonates on natural and stress-induced senescence in Arabidopsis.
abstract: Jasmonic acid and related oxylipins are controversially discussed to be involved in regulating the initiation and progression of leaf senescence. To this end, we analyzed profiles of free and esterified oxylipins during natural senescence and upon induction of senescence-like phenotypes by dark treatment and flotation on sorbitol in Arabidopsis (Arabidopsis thaliana). Jasmonic acid and free 12-oxo-phytodienoic acid increased during all three processes, with the strongest increase of jasmonic acid after dark treatment. Arabidopside content only increased considerably in response to sorbitol treatment. Monogalactosyldiacylglycerols and digalactosyldiacylglycerols decreased during these treatments and aging. Lipoxygenase 2-RNA interference (RNAi) plants were generated, which constitutively produce jasmonic acid and 12-oxo-phytodienoic acid but do not exhibit accumulation during natural senescence or upon stress treatment. Chlorophyll loss during aging and upon dark incubation was not altered, suggesting that these oxylipins are not involved in these processes. In contrast, lipoxygenase 2-RNAi lines and the allene oxid synthase-deficient mutant dde2 were less sensitive to sorbitol than the wild type, indicating that oxylipins contribute to the response to sorbitol stress.
authors.affiliation: Julius-von-Sachs-Institute for Biosciences, Pharmaceutical Biology, Biocenter, University of Wuerzburg, 97082 Wuerzburg, Germany.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Seltmann
authors.forename: Nadja E
authors.initials: NE
authors.lastname: Stingl
authors.forename: Jens K
authors.initials: JK
authors.lastname: Lautenschlaeger
authors.forename: Markus
authors.initials: M
authors.lastname: Krischke
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Mueller
authors.forename: Susanne
authors.initials: S
authors.lastname: Berger
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D003517:Cyclopentanes / Q000378:metabolism*; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism*; D034741:RNA, Small Interfering; D013312:Stress, Physiological
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D034741:RNA, Small Interfering; C011006:jasmonic acid; D008084:Lipoxygenase