2011 Fiscal Year Final Research Report
Elucidation of steroidal backbone synthesis for plant defensive mechanisms
| Project/Area Number |
22780100
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Bioproduction chemistry/Bioorganic chemistry
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
OHYAMA Kiyoshi 東京工業大学, 大学院・理工学研究科, 助教 (20391899)
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| Project Period (FY) |
2010 – 2011
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| Keywords | 生合成 / ラノステロール / シクロアルテノール / 防御応答 / トマト / メチルジャ / メバロン酸 |
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| Research Abstract |
We hypothesized that a part of tomatine, a steroidal alkaloid in tomato, is biosynthesized via lanosterol, and tomatine content is increased by enhancing lanosterol pathway with MeJA treatment. In order to investigate the variation of tomatine content by the elicitation with MeJA, tomato seedlings were incubated for 1d, 3d, and 7d in MS medium including 5μM MeJA. The seedlings were harvested, extracted and subjected to quantitative LC-MS analysis for tomatine. The content of tomatine was 4-fold higher than in the untreated seedlings, while the contents of cholesterol and phytosterol were held constant. In addition, the feeding experiments of[ 6-^<13> C^2H_3] MVL were performed using tomato seedlings and the backbone synthesis of tomatine was analyzed by<13>^C-NMR. As a result, the cycloartenol pathway was found to be an exclusive route with little or no lanosterol pathway in a normal growth condition. By 5μM MeJA treatment the contribution of the lanosterol pathway to tomatine biosynthesis was increased up to ca. 3% of the cycloartenol pathway. However the sterols were biosynthesized by the cycloartenol pathway with little or no lanosterol pathway in the both conditions. From these results, it is suggested that an increase in tomatine biosynthesis occurs independently of phytosterol biosynthesis.
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