title: Compartmentation and dynamics of flavone metabolism in dry and germinated rice seeds.
abstract: Among secondary metabolites, flavonoids are particularly important for the plant life cycle and could be beneficial for human health. The study of Arabidopsis thaliana transparent testa mutants showed that seed flavonoids are important for environmental adaptation, reactive oxygen species homeostasis, dormancy and longevity. Compared with Arabidopsis and maize (Zea mays L.), far less research has been conducted on rice (Oryza sativa L.) particularly for cultivars with non-pigmented seeds. In this study, we describe the localization, nature and relative abundance of flavonoids in mature and germinated non-pigmented Nipponbare seeds using a combination of confocal microscopy, mass spectrometry and gene expression analysis. The mature seed exclusively accumulates flavones mostly in the embryo and to a lesser extent in the pericarp/testa. Due to the variety of flavone conjugation patterns, 21 different flavones were identified, including sulfated flavones never mentioned before in cereals. Schaftoside (apigenin-6-C-glucoside-8-C-arabinoside) and its two isomers represent nearly 50% of all rice seed flavones and are the only flavonoids accumulated in the pericarp/testa seed compartment. These 21 conjugated flavones showed a very stable profile during rice seed germination sensu stricto, while expression of key flavone synthesis genes strongly increases before the completion of germination. We discuss the potential roles of these rice seed flavones in a seed biology context.
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France AgroParisTech, Chaire of Plant Physiology, 16 rue Claude Bernard, F-75231 Paris Cedex 05, France Present address: University of Amsterdam, Swammerdam Institute for Life Sciences, Department of Plant Physiology, 1098 XH Amsterdam, The Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: Galland
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Boutet-Mercey
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France AgroParisTech, Chaire of Plant Physiology, 16 rue Claude Bernard, F-75231 Paris Cedex 05, France.
authors.forename: Imen
authors.initials: I
authors.lastname: Lounifi
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France AgroParisTech, Chaire of Plant Physiology, 16 rue Claude Bernard, F-75231 Paris Cedex 05, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Godin
authors.affiliation: Unité de Recherche en Génomique Végétale (URGV), UMR INRA 1165-Université d'Evry Val d'Essonne-ERL CNRS 8196, 2 rue G. Crémieux, CP 5708, F-91057 Evry Cedex, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Balzergue
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Grandjean
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
authors.forename: Halima
authors.initials: H
authors.lastname: Morin
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
authors.forename: François
authors.initials: F
authors.lastname: Perreau
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Debeaujon
authors.affiliation: INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France AgroParisTech, Chaire of Plant Physiology, 16 rue Claude Bernard, F-75231 Paris Cedex 05, France loic.rajjou@agroparistech.fr.
authors.forename: Loïc
authors.initials: L
authors.lastname: Rajjou
mesh_terms: D002853:Chromatography, Liquid; D047309:Flavones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018525:Germination; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D018749:RNA, Plant / Q000235:genetics; D012639:Seeds / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D053719:Tandem Mass Spectrometry; D014867:Water / Q000502:physiology
chemical_list: D047309:Flavones; D018749:RNA, Plant; D014867:Water
keywords: Compartmentation; Embryo; Flavonoid; Germination; Rice; Seed