title: The circadian clock-associated gene gigantea1 affects maize developmental transitions.
abstract: The circadian clock is an internal timing mechanism that allows plants to make developmental decisions in accordance with environmental conditions. In model plants, circadian clock-associated gigantea (gi) genes are directly involved in control of growth and developmental transitions. The maize gigantea1 (gi1) gene is the more highly expressed of the two gi homeologs, and its function is uncharacterized. To understand the role of gi1 in the regulatory networks of the maize circadian clock system, gi1 mutants were evaluated for changes in flowering time, phase change and growth control. When grown in long-day (LD) photoperiods, gi1 mutants flowered earlier than non-mutant plants, but this difference was not apparent in short-day (SD) photoperiods. Therefore, gi1 participates in a pathway that suppresses flowering in LD photoperiods, but not in SD. Part of the underlying cause of early flowering was up-regulated expression of the FT-like floral activator gene zea mays centroradialis8 (zcn8) and the CONSTANS-like flowering regulatory gene constans of zea mays1 (conz1). gi1 mutants also underwent vegetative phase change earlier and grew taller than non-mutant plants. These findings indicate gi1 has a repressive function in multiple regulatory pathways that govern maize growth and development.
authors: Department of Plant & Microbial Biology, University of California, Berkeley, CA 94720, USA.
authors: Claire
authors: C
authors: Bendix
authors: Plant Gene Expression Center, USDA-ARS, Albany, CA, 94710, USA.
authors: Juan M
authors: JM
authors: Mendoza
authors: Department of Plant & Microbial Biology, University of California, Berkeley, CA, 94720, USA.
authors: Desiree N
authors: DN
authors: Stanley
authors: Crop Genetics Research, Pioneer Hi Bred-A DuPont Business, Johnston, IA, 50130, USA.
authors: Robert
authors: R
authors: Meeley
authors: Department of Plant & Microbial Biology, University of California, Berkeley, CA, 94720, USA.|Plant Gene Expression Center, USDA-ARS, Albany, CA, 94710, USA.
authors: Frank G
authors: FG
authors: Harmon
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D057906:Circadian Clocks / Q000235:genetics*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D017440:Photoperiod; D063245:Plant Development / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000254:growth & development; D015398:Signal Transduction / Q000235:genetics; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins
keywords: circadian clock; conz1; development; flowering time; gigantea; growth; maize; phase change; photoperiod; zcn8