title: The AtSUC5 sucrose transporter specifically expressed in the endosperm is involved in early seed development in Arabidopsis.
abstract: The sucrose transporter gene AtSUC5 was studied as part of a programme aimed at identifying and studying the genes involved in seed maturation in Arabidopsis. Expression profiling of AtSUC5 using the technique of real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR) showed that the gene was specifically and highly induced during seed development between 4 and 9 days after flowering (DAF). Analysis of the activity of the AtSUC5 promoter in planta was consistent with this timing, and suggested that AtSUC5 expression is endosperm specific, spreading from the micropylar to the chalazal pole of the filial tissue. To demonstrate the function of AtSUC5, the corresponding cDNA was used to complement a sucrose uptake-deficient yeast mutant, thus confirming its sucrose transport capacity. To investigate the function in planta, three allelic mutants disrupted in the AtSUC5 gene were isolated and characterized. A strong but transient reduction in fatty acid concentration was observed in mutant seeds 8 DAF. This biochemical phenotype was associated with a slight delay in embryo development. Taken together, these data demonstrated the role of the AtSUC5 carrier in the nutrition of the filial tissues during early seed development. However, additional sugar uptake systems, which remain to be characterized, must be functional in developing seeds, especially during maturation of the embryo.
authors.affiliation: Unité de Biologie des Semences, UMR 204 INA P-G/INRA, RD10, 78026 Versailles Cedex, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Baud
authors.forename: Sylvie
authors.initials: S
authors.lastname: Wuillème
authors.forename: Rémi
authors.initials: R
authors.lastname: Lemoine
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Kronenberger
authors.forename: Michel
authors.initials: M
authors.lastname: Caboche
authors.forename: Loïc
authors.initials: L
authors.lastname: Lepiniec
authors.forename: Christine
authors.initials: C
authors.lastname: Rochat
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000096:biosynthesis* / Q000502:physiology; D005810:Multigene Family; D010940:Plant Proteins / Q000096:biosynthesis* / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; C078729:sucrose transport protein, plant