title: Regulation of RhSUC2, a sucrose transporter, is correlated with the light control of bud burst in Rosa sp.
abstract: In roses, light is a central environmental factor controlling bud break and involves a stimulation of sugar metabolism. Very little is known about the role of sucrose transporters in the bud break process and its regulation by light. In this study, we show that sugar promotes rose bud break and that bud break is accompanied by an import of sucrose. Radio-labelled sucrose accumulation is higher in buds exposed to light than to darkness and involves an active component. Several sucrose transporter (RhSUC1, 2, 3 and 4) transcripts are expressed in rose tissues, but RhSUC2 transcript level is the only one induced in buds exposed to light after removing the apical dominance. RhSUC2 is preferentially expressed in bursting buds and stems. Functional analyses in baker's yeast demonstrate that RhSUC2 encodes a sucrose/proton co-transporter with a K(m) value of 2.99 mm at pH 4.5 and shows typical features of sucrose symporters. We therefore propose that bud break photocontrol partly depends upon the modulation of sucrose import into buds by RhSUC2.
authors.affiliation: Universite D'Angers, UFR Sciences, UMR-462 SAGAH, 2 Bd Lavoisier, F-49045 Angers Cedex, France.
authors.forename: Clemence
authors.initials: C
authors.lastname: Henry
authors.forename: Amelie
authors.initials: A
authors.lastname: Rabot
authors.forename: Maryse
authors.initials: M
authors.lastname: Laloi
authors.forename: Eric
authors.initials: E
authors.lastname: Mortreau
authors.forename: Monique
authors.initials: M
authors.lastname: Sigogne
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leduc
authors.forename: Rémi
authors.initials: R
authors.lastname: Lemoine
authors.forename: Soulaiman
authors.initials: S
authors.lastname: Sakr
authors.forename: Alain
authors.initials: A
authors.lastname: Vian
authors.forename: Sandrine
authors.initials: S
authors.lastname: Pelleschi-Travier
mesh_terms: D001692:Biological Transport / Q000528:radiation effects; D008027:Light; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D018547:Plant Stems / Q000378:metabolism / Q000528:radiation effects; D027826:Rosa / Q000502:physiology* / Q000528:radiation effects; D013395:Sucrose / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; C078729:sucrose transport protein, plant; D013395:Sucrose