2002 Fiscal Year Final Research Report Summary
Molecular and functional analysis of genes involved in germination response to temperature
| Project/Area Number |
12640640
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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 |
植物生理
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| Research Institution | Meiji University |
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Principal Investigator |
KAWAKAMI Naoto Meiji University, School of Agriculture, Associate Professor, 農学部, 助教授 (10211179)
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| Project Period (FY) |
2000 – 2002
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| Keywords | seed germination / thermo-inhibition / seed coat / mutant / abscisic acid / T-DNA tagging / dormancy / mapping |
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| Research Abstract |
Seed germination is determined by the state of dormancy itself and environmental conditions. Temperature is one of the critical environmental cues for germination of plant seeds, and the upper limit temperature for germination has been shown to be change during the annual dormancy cycle of the buried seeds in soil. To understand the regulation mechanism of germination by temperature, we selected five high temperature resistant germination mutants from 20, 000 T-DNA tag lines of Arabidopsis. Genetic analysis indicated that four mutations excluding TRW124-4 are recessive, and each segregates as a single locus but not tagged by T-DNA. All the mutant lines produced the seeds with reduced dormancy. The seeds of TRW71-1 showed maternal effect on seed coat color and the germination phenotypes. Genetic complementation analysis indicated that the mutation of TRW71-1 is allelic to tt7. These results suggest that 1) dormancy and temperature response mechanism of seeds are closely related, and 2) both embryo and seed coat contribute to germination inhibition at high temperature.
The seeds of TRW134-15 and TRW187 showed reduced response to ABA. Genetic complementation analysis indicated that TRW187 is allelic to abi3. Some of the known ABA deficient and insensitive mutants also showed high temperature resistant germination. ABA content in seeds was higher at 34℃ than at 22℃, and ABA biosynthesis inhibitor fluridone alleviated the thermo-inhibition of wild type seeds. These observations suggest that induction of ABA synthesis by high temperature is involved in the germination control mechanism. The mutation of TRW13-1 was mapped on the bottom arm of chromosomal, and designated as temperature resistant germination 1 (trgl). TRG1 might code for a novel gene that involved in germination control mechanism.
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