1998 Fiscal Year Final Research Report Summary
Reguratory mechanisms of seed germination in rice
| Project/Area Number |
09660004
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Breeding science
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| Research Institution | Nagoya University |
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Principal Investigator |
YAMAGUCHI Jyunji Nagoya University Bioscience Center, Associate Professor, 生物分子応答研究センター, 助教授 (10183120)
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| Project Period (FY) |
1997 – 1998
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| Keywords | alpha-amylase / transcriptional regulation / particle gun bombardment / hexose kinase / sugar sensor / cis-acting elements / G motif / GATA motif |
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| Research Abstract |
There is increasing evidence showing that in rice alpha-amylase gene expression is controlled not only by the classical hormonal regulation, but also by feed-back metabolite repression. In rice, modulation of alpha-amylase genes by carbohydrates and other metabolite is well described. At least ten genes encode for alpha-amylase isoforms in rice, but two of them are strongly under the control of sugar level, namely RAmy3D and RAmy3E.While the expression of the RAmy3D gene is restricted to the embryo, Ramy1A gene is expressed in both the embryo and aleurone layers. We used a transient expression system (rice embryos) to study the cis-acting elements involved in the sugar repression of the Ramy1A and RAmy3D promoter activity. Gibberellin-response cis-elements of GARE (TAACAAA) and pyrimidine box (CCTTTT) of Ramy1A gene promoter were partially involved in the sugar regulation (Morita et al. 1998). On the contrary, Site-directed mutagenesis of the 50-bp nucleotide sequences from -172 to -123 for RAmy3D gene promoter revealed that consensus sequences of G motif (TACGTA) and TATCCA T/C motif (GATA motif as its antisense sequence) are responsible for sugar repression.
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