2004 Fiscal Year Final Research Report Summary
The genome dynamics and function in higher plants
| Project/Area Number |
14204075
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
遺伝
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| Research Institution | National Institute for Basic Biology (2004)
Okazaki National Research Institutes (2002-2003) |
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Principal Investigator |
IIDA Shigeru National Institute for Basic Biology, Professor, 分子遺伝学研究部門, 教授 (30012777)
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| Co-Investigator(Kenkyū-buntansha) |
TERADA Rie National Institute for Basic Biology Division of Molecular Genetics, Research associate, 分子遺伝学研究部門, 助手 (30137799)
HOSHINO Atsushi National Institute for Basic Biology Division of Molecular Genetics, Research associate, 分子遺伝学研究部門, 助手 (80312205)
TSUGANE Kazuo National Institute for Basic Biology Division of Molecular Genetics, Research associate, 分子遺伝学研究部門, 助手 (50343744)
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| Project Period (FY) |
2002 – 2004
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| Keywords | morning-glories / rice / genome / spontaneous mutation / transposon / mutable allele / gene targeting / gene tagging |
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| Research Abstract |
The spontaneous magenta, pink and fuchsia mutants in I. nil, I. purpurea and I. tricolor exhibit reddish flowers, respectively, while their wild-type flowers display blue or dark purple flowers. We have identified that these mutants carry either point mutations or transposon insertions within the F3'H gene encoding flavonoid 3'-hydroxylase that mediates hydroxylation of the 3' position of the B-ring of naringenin and dehydrokaempferol in anthocyanin pigment biosynthesis. The reddish-purple buds of the wild-type I. nil change into blue open flowers, and the shift in the flower coloration correlates with an increase in the vacuolar pH of the flower epidermal cell. In the mutant deficient in the NHX1 gene for the vacuolar Na+/H+ antiporter, the vacuolar alkalization occurs only partially, and reddish-purple buds become purple open flowers. We have identified a novel vacuolar Na+/H+ antiporter gene NHX2, which is one of the genes responsible for converting reddish-purple buds into purple open flowers by partially increasing vacuolar pH in the absence of the NHX1 activity. The dusky mutants of I. nil displaying reddish-brown or purplish-gray flowers were found to be deficient in a novel glycosylation enzyme for anthocyanin biosynthesis, UDP-glucose : anthocyanidin 3-O-glucoside-2"-O-glucosyltransferase (3GGT), which mediates the glucosylation of anthocyanidin 3-O-glucosides to yield 3-O-sophorosides. All of the dusky mutants examined were shown to carry 4 by insertions at the identical position in the 3GGT gene, and the insertions caused frameshift mutations.
Modification of genes through homologousrecombination termed gene targeting is the most direct method to characterize gene function, and we have succeeded in modifying the rice genomic sequence of the Waxy gene reproducibly by using a strong positive-negative selection. We also identified a novel rice DNA transposon, nDart, which can be used for gene tagging in rice.
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