| Project/Area Number |
17580004
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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 | The University of Tokyo |
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Principal Investigator |
YOSHIDA Kaoru T. The University of Tokyo, Graduate School of Agriculture and Life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (70183994)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAIWA Fumio National Institute of Agrobiological Sciences, Transgenic Crop Research and Development Center, Team Leader, 農業生物資源研究所・新生物質源創出研究グループ, チーム長 (20370661)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Phytoremediation / Phosphorus / Phytic acid / Molecular breeding / Environmental clean-up / GMO / Hyperaccumulator / ファイトレメディエーション / 遺伝子組み換え植物 |
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| Research Abstract |
Phytic acid, myo-inositol-hexakisphosphate (InsP_6), is a storage form of phosphorus in plants. Despite many physiological investigations of phytic acid accumulation and storage, little is known at the molecular level about its biosynthetic pathway in plants. Identification of the genes involved in phytic acid biosynthesis should enable specific molecular sense approaches to phosphorus removal from polluted environment.
We identified 12 genes from rice that code for the enzymes that may be involved in the metabolism of inositol phosphates. Outstanding up-regulation of the four genes, a MIPS, an IPK1, and two ITP5/6Ks in embryos, suggested that they play a significant role in phytic acid biosynthesis in seeds. Rice homolog, OsIPK1 could rescue the lethality of yeast ipk1 mutant cells, suggesting that OsIPK1 encodes a functional IPK1. To elucidate the function of these genes in phytic acid biosynthesis, reverse genetics were performed. The transgenic rice with antisense OsMIPS, OsIPK1, and OsITP5/6K-6 cause an increased Pi level in T_1 seeds, suggesting a major role for these genes in phytic acid biosynthesis in developing seeds.
We produced transgenic rice with sense OsMIPS and OsIPK1 driven by actin promoter. The seeds of the transformants contained lower level of inorganic phosphates than non-transformants. This indicates that phytic acid biosynthesis is activated in the transformants. We also confirmed that the expression levels of these genes of transformants were higher than those of non-transformants. They would offer hopeful breeding materials for producing a hyperaccumulator of phosphorus to remove phosphorus from eutrophied lakes.
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