Characterization and functional analysis of three wheat genes with homology to the CONSTANS flowering time gene in transgenic rice.
The CONSTANS (CO) gene of Arabidopsis plays a key role in the photoperiodic flowering pathway. To investigate photoperiod responses in cereals in more detail, we isolated three kinds of CO/Hd1 (rice ortholog of CO) homolog from hexaploid wheat, derived from the A, B, and D genomes and designated as wheat ortholog of CO from A genome (TaHd1-1), TaHd1-2, and TaHd1-3, respectively. They were highly similar to each other and to Hd1, and in addition harbored two conserved regions: two zinc finger motifs and CONSTANS, CONSTANS-LIKE and TIMING OF CAB EXPRESSION 1 (CCT) domain like CO/Hd1. They were located on the long arm of the homoeologous chromosome 6. TaHd1-2 harbored a 63-bp deletion at the promoter region containing the GATA-1 box, and consequently, we detected no subsequent transcript. The TaHd1-1 genomic clone was introduced to a rice line deficient in Hd1 function. Transgenic plants complemented the functions of rice Hd1: they promoted heading under short-day (SD) conditions and delayed it under long-day (LD)/natural conditions, indicating that Hd1 proteins from SD and LD plants share common structures and functions.
Nemoto
Yasue
Y
Kihara Institute for Biological Research and Graduate School of Integrated Science, Yokohama City University, Maioka-cho 641-12, Yokohama 244-0813, Japan.
Kisaka
Mayumi
M
Fuse
Takuichi
T
Yano
Masahiro
M
Ogihara
Yasunari
Y
D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics* / Q000254:growth & development
D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D018076:DNA, Complementary; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors