| Project/Area Number |
11556012
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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 | 展開研究 |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | Tohoku University |
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Principal Investigator |
MINAMISAWA Kiwamu Graduate School of Life Sciences, Professor, 大学院・生命科学研究科, 教授 (70167667)
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| Co-Investigator(Kenkyū-buntansha) |
YUHASI Ken-ichi JSPS fellow, 特別研究員
EZURA Hiroshi University of Tukuba, Associate Professor, 農林学系・遺伝子実験センター, 助教授 (00332552)
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| Project Period (FY) |
1999 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 2002: ¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2001: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2000: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Bradyrhizobium elkanii / ethylene / soybean / Lotus japonicus / rhizobitoxine / Agrobacterium / rhizobia / siratro / デサチュラーゼ / ダイズ根粒菌 |
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| Research Abstract |
We have investigated rhizobitoxine biosynthetic pathway and the function in Bradyrhizobium elkanii. In addition, we examined whether the ability to produce rhizobitoxine may improve rhizobial symbiosis and Agrobacterium-mediated transformation. DNA sequence and mutational analysis of rhizobitoxine biosynthetic genes revealed that at least rtxA and rtxC are requiered for rhizobitoxine biosynthesis in Bradyrhizobium elkanii. Application of ethylene precursor and inhibitors for ethylene biosynthesis and perception suggested that an ethylene-mediated signaling pathway is involved in the nodulation process even in the determinate nodulators including Lotus japonicus and Macroptilium atropurpureum. Rhizobitoxine competitively inhibited 1-aminocyclopropane-1-carboxylate synthase in ethylene biosynthetic pathway of host plants, and enhanced nodulation and competitiveness of B. elkanii on M. atropurpureum. Interestingly, Rhizobitoxine enhancement of competitive nodulation occurred at a late stage in the time-course of nodulation. We have been trying to confer the ability to produce rhizobitoxine of B. elkanii into other gram-negative bacteria by plasmids carrying rtxAC.
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