title: Photoperiodic control of carbon distribution during the floral transition in Arabidopsis.
abstract: Flowering is a crucial process that demands substantial resources. Carbon metabolism must be coordinated with development through a control mechanism that optimizes fitness for any physiological need and growth stage of the plant. However, how sugar allocation is controlled during the floral transition is unknown. Recently, the role of a CONSTANS (CO) ortholog (Cr-CO) in the control of the photoperiod response in the green alga Chlamydomonas reinhardtii and its influence on starch metabolism was demonstrated. In this work, we show that transitory starch accumulation and glycan composition during the floral transition in Arabidopsis thaliana are regulated by photoperiod. Employing a multidisciplinary approach, we demonstrate a role for CO in regulating the level and timing of expression of the GRANULE BOUND STARCH SYNTHASE (GBSS) gene. Furthermore, we provide a detailed characterization of a GBSS mutant involved in transitory starch synthesis and analyze its flowering time phenotype in relation to its altered capacity to synthesize amylose and to modify the plant free sugar content. Photoperiod modification of starch homeostasis by CO may be crucial for increasing the sugar mobilization demanded by the floral transition. This finding contributes to our understanding of the flowering process.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Seville, Spain.
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Ortiz-Marchena
authors.forename: Tomás
authors.initials: T
authors.lastname: Albi
authors.forename: Eva
authors.initials: E
authors.lastname: Lucas-Reina
authors.forename: Fatima E
authors.initials: FE
authors.lastname: Said
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Romero-Campero
authors.forename: Beatriz
authors.initials: B
authors.lastname: Cano
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Ruiz
authors.forename: José M
authors.initials: JM
authors.lastname: Romero
authors.forename: Federico
authors.initials: F
authors.lastname: Valverde
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D017440:Photoperiod; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012995:Solubility; D013213:Starch / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D002244:Carbon; D013213:Starch