Rice Indeterminate 1 (OsId1) is necessary for the expression of Ehd1 (Early heading date 1) regardless of photoperiod.
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.
Park
Soon Ju
SJ
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.
Kim
Song Lim
SL
Lee
Shinyoung
S
Je
Byoung Il
BI
Piao
Hai Long
HL
Park
Sung Han
SH
Kim
Chul Min
CM
Ryu
Choong-Hwan
CH
Park
Su Hyun
SH
Xuan
Yuan-hu
YH
Colasanti
Joseph
J
An
Gynheung
G
Han
Chang-deok
CD
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
C112487:Id1 protein, plant; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors