title: Rice Indeterminate 1 (OsId1) is necessary for the expression of Ehd1 (Early heading date 1) regardless of photoperiod.
abstract: Indeterminate 1 (Id1), a classical flowering gene first reported in 1946, is one of the earliest genes whose expression in leaf tissues affects the floral transition in the shoot meristem. How Id1 is integrated into the flowering process is largely unknown. In this study, we examined the genetic action of the rice (Oryza sativa) ortholog OsId1. In rice, OsId1 is preferentially expressed in young leaves, but the overall expression pattern is broader than that in maize (Zea mays). OsId1 is able to activate transcription in yeast. RNAi mutants show a delay in flowering under both short-day (SD) and long-day (LD) conditions. OsId1 regulates the expression of Ehd1 (Early heading date 1) and its downstream genes, including Hd3a (a rice ortholog of FT) and RFT1 (Rice Flowering Locus T1), under both SD and LD conditions. In rice, the expression of Ehd1 is also controlled by the photoperiodic flowering genes OsGI (a rice ortholog of GI) and OsMADS51. However, the expression of OsId1 is independent of OsGI, OsMADS51, and OsMADS50 (a rice SOC1 ortholog). This study demonstrates that the activation of Ehd1 by OsId1 is required for the promotion of flowering.
authors.affiliation: Division of Applied Life Science (BK21 Program), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Soon Ju
authors.initials: SJ
authors.lastname: Park
authors.forename: Song Lim
authors.initials: SL
authors.lastname: Kim
authors.forename: Shinyoung
authors.initials: S
authors.lastname: Lee
authors.forename: Byoung Il
authors.initials: BI
authors.lastname: Je
authors.forename: Hai Long
authors.initials: HL
authors.lastname: Piao
authors.forename: Sung Han
authors.initials: SH
authors.lastname: Park
authors.forename: Chul Min
authors.initials: CM
authors.lastname: Kim
authors.forename: Choong-Hwan
authors.initials: CH
authors.lastname: Ryu
authors.forename: Su Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Yuan-hu
authors.initials: YH
authors.lastname: Xuan
authors.forename: Joseph
authors.initials: J
authors.lastname: Colasanti
authors.forename: Gynheung
authors.initials: G
authors.lastname: An
authors.forename: Chang-deok
authors.initials: CD
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D017440:Photoperiod; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
chemical_list: C112487:Id1 protein, plant; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors