title: Enzymatic and Non-Enzymatic Mechanisms Contribute to Lipid Oxidation During Seed Aging.
abstract: Storage of seeds is accompanied by loss of germination and oxidation of storage and membrane lipids. A lipidomic analysis revealed that during natural and artificial aging of Arabidopsis seeds, levels of several diacylglycerols and free fatty acids, such as linoleic acid and linolenic acid as well as free oxidized fatty acids and oxygenated triacylglycerols, increased. Lipids can be oxidized by enzymatic or non-enzymatic processes. In the enzymatic pathway, lipoxygenases (LOXs) catalyze the first oxygenation step of polyunsaturated fatty acids. Analysis of lipid levels in mutants with defects in the two 9-LOX genes revealed that the strong increase in free 9-hydroxy- and 9-keto-fatty acids is dependent on LOX1 but not LOX5. Fatty acid oxidation correlated with an aging-induced decrease of germination, raising the question of whether these oxylipins negatively regulate germination. However, seeds of the lox1 mutant were only slightly more tolerant to aging, indicating that 9-LOX products contribute to but are not the major cause of loss of germination during aging. In contrast to free oxidized fatty acids, accumulation of oxygenated triacylglycerols upon accelerated aging was mainly based on non-enzymatic oxidation of seed storage lipids.
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Ayla
authors.initials: A
authors.lastname: Oenel
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Agnes
authors.initials: A
authors.lastname: Fekete
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Krischke
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Faul
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Gresser
authors.affiliation: CEA, CNRS UMR7265, Aix-Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Havaux
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Mueller
authors.affiliation: Julius-von-Sachs-Institute, Pharmaceutical Biology, University of Wuerzburg, Julius-von-Sachs-Platz, Wuerzburg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Berger
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics / Q000502:physiology; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D012639:Seeds / Q000201:enzymology* / Q000378:metabolism* / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D008084:Lipoxygenase
keywords: Arabidopsis; Lipid oxidation; Lipoxygenase; Seed deterioration