研究課題/領域番号 |
18J20784
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研究種目 |
特別研究員奨励費
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配分区分 | 補助金 |
応募区分 | 国内 |
研究分野 |
環境農学(含ランドスケープ科学)
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研究機関 | 九州大学 |
研究代表者 |
SURIYASAK CHETPHILIN 九州大学, 生物資源環境科学府, 特別研究員(DC1)
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研究期間 (年度) |
2018-04-25 – 2021-03-31
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研究課題ステータス |
交付 (2020年度)
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配分額 *注記 |
2,200千円 (直接経費: 2,200千円)
2020年度: 700千円 (直接経費: 700千円)
2019年度: 700千円 (直接経費: 700千円)
2018年度: 800千円 (直接経費: 800千円)
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キーワード | Heat stress / Rice / Grain filling / Epigenetics / Transgeneration / Flowering / Thermotolerance |
研究実績の概要 |
Seeds developed under high temperature showed significantly delayed germination compared to control under the same non-stressed condition. This delay in germination was due to transcriptional changes after imbibition caused by hyper-methylation of ABA catabolism genes, and α-amylase gene. Higher methylation levels of target genes were confirmed by both Chop-qPCR and MeDIP-qPCR, which showed similar results stating that hyper-methylation of ABA catabolism genes and of α-amylase genes was involved in delayed seed germination of heat stressed seeds.
At natural condition, plants grown from heat stressed seeds developed more tillers together with reduced height during vegetative growth despite unchanged total biomass compared to control plants. At harvest, heat stressed plants showed higher total panicle per plant, resulting in higher total spikelet number resulting higher yield. Other yield components, spikelet per panicle, 1000-grain weight, harvest index and seed setting rate, remained unchanged.
We observed that early flowering phenotype and changes in leaf morphology were not cultivar-specific traits, by observing other 22 Japonica rice cultivars. Cultivar differences show that heat stress during grain filling induces transgenerational memory to the progeny to some content depending on cultivars.
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現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Continuous cultivation of transgenerational plants went well as expected. We obtained the 5th and 6th generation seeds this year for cv. Nipponbare and cv. Hinohikari, respectively. Also, heat stress removal generations (HC and HCC) were also cultivated. Heat stress during grain filling induced many changes in progeny phenotype, from germination to grain filling stage, which all of these changes were well recored and analyzed. DNA methylation levels for germination traits were confirmed with both Chop-qPCR and MeDIP-qPCR with similarly positive results. Morphology changes of flag leaves were confirmed for the second year replicate added up with other 22 cultivars. Thus, it was considered that this research went well as scheduled and we expect further research to be done more in the next year.
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今後の研究の推進方策 |
In all, heat stress during grain filling causes many phenotypic changes of offspring under both natural condition and under heat stress condition. Thus, epigenome analysis of both control and heat stress seeds via whole genome BS-Seq method for DMRs (Differentially methylated regions) and DMPs (Differentially methylated positions) clustering.
Cultivation for replicate year to confirm changes in phenotype of heat stressed progeny will be taken place and natural condition and under high temperature conditions. HC and HCC stress removal generation plants will also be cultivated and observed.
In addition, the 5th generation of cv. Hinohikari and Nipponbare will be cultivated in the field at natural condition to observed transgenerational effects on grain yield and quality in field's large scale. which is important for agronomy study. The 6th generation seeds of cv. Nipponbare and 7th generation seeds of cv. Hinohikari will be cultivated this year. HCC, a three stress removal generation, will also be cultvated this year.
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