| Project/Area Number |
16380005
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Mie University |
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Principal Investigator |
KOWYAMA Yasuo Mie University, Graduate School of Bioresources, Professor, 大学院生物資源学研究科, 教授 (80024579)
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| Co-Investigator(Kenkyū-buntansha) |
KAKEDA Katsuyuki Mie University, Graduate School of Bioresources, Associate Professor, 大学院生物資源学研究科, 助教授 (50221867)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥15,400,000 (Direct Cost: ¥15,400,000)
Fiscal Year 2006: ¥4,900,000 (Direct Cost: ¥4,900,000)
Fiscal Year 2005: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 2004: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Self-incompatibility / Convolvulaceae / Ipomoea / Sweet potato relatives / Sexual reproduction / Molecular genetics / Genome analysis / 胞子体型自家不和合性 |
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| Research Abstract |
Self-incompatibility (SI) is a genetic system that prevents self-fertilization and thereby promotes out-crossing to maintain genetic diversity in plant populations. The SI system works through the rejection of self-pollen following the recognition of self and non-self pollen by the pistil. In the plant family, Convolvulaceae, several species of Ipomoea possess a sporophytic type of SI that is regulated by a single multiallelic S-locus. The present study was performed to identify the S-locus genes involved in the self-pollen recognition and to reveal molecular mechanism of the SI system in Ipomoea. Research results obtained are summarized as follows. (1) Fine genetic map of DNA markers was constructed in the vicinity of the S-locus. (2) Using a map-based positional cloning strategy, several genomic clones covering the S-locus were screened from bacterial artificial chromosome (BAC) and cosmid libraries of three S haplotypes. (3) Sequence analysis of the isolated clones showed that the S-loci were delimited to the S haplotype-specific divergent regions (SDRs) spanning 30 to 95 kb in size. (4) From gene expression analyses by Northern blot and RT-PCR of mRNAs, three stigma-specific genes (SE1, SE2, SEA) and an anther-specific gene (AB2) in the SDRs were identified as candidates encoding pistil and pollen determinants of the SI, respectively. (5) Transformants introduced with RNAi constructs of the stigma-specific genes showed no changes in the SI phenotypes, indicating that the stigma-specific genes might be functioned as complementary. (6) The present study revealed that these stigma specific candidates showed no homologies with the S-locus genes reported to date from other plants, and suggests that a unique molecular mechanism is involved in the SI system of Ipomoea plants.
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