| Project/Area Number |
21657017
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| Research Category |
Grant-in-Aid for Challenging Exploratory Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Plant molecular biology/Plant physiology
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| Research Institution | Saga University |
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Principal Investigator |
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| Project Period (FY) |
2009 – 2011
|
| Project Status |
Completed (Fiscal Year 2011)
|
| Budget Amount *help |
¥3,410,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥210,000)
Fiscal Year 2011: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2010: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2009: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | 根粒 / 共生 / フィトクロム / 光形態形成 / 植物微生物相互作用 / ジャスモン酸 / ミヤコグサ / 光質 / 変異体 / 赤色光 / シグナル伝達 / スクリーニング |
|---|
| Research Abstract |
Light is critical for supplying carbon to the energetically expensive, nitrogen-fixing symbiosis between legumes and rhizobia. In this study, I show that Phytochrome B(phyB) is part of the monitoring system to detect suboptimal light conditions, which normally suppress Lotus japonicus nodule development following Mesorhizobium loti inoculation. I found that the number of nodules produced by L. japonicus phyB mutants is significantly reduced compared to that of wild-type MG20. To explore causes other than photoassimilate production, the possibility that local control by the root genotype occurred was investigated by grafting experiments. The results showed that the shoot and not the root genotype is responsible for root nodule formation. To explore systemic control mechanisms exclusive of photoassimilation, we moved wild-type MG20 plants from white light to conditions that differed in their ratios of low or high red(R)/ far-red(FR) light. In low R/ FR light, the number of MG20 root nodules dramatically decreased compared to plants grown in high R/ FR even though photoassimilate content was higher for plants grown under low R/ FR. Also, the expression of jasmonic acid(JA)-responsive genes decreased in both low R/ FR light-grown wild-type and in white light-grown phyB mutant plants, and correlated with decreased JA-Ile content in the phyB mutant. Moreover, both infection thread formation and root nodule formation were positively influenced by JA treatment of wild-type plants grown in low
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