2007 Fiscal Year Final Research Report Summary
The fumctional siRAs inducing flowering of chrysanthemum plants
| Project/Area Number |
17380022
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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 | 一般 |
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| Research Field |
Horticulture/Landscape architecture
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| Research Institution | Kyoto University |
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Principal Investigator |
HOSOKAWA Munetaka Kyoto University, Agronomy, Assistant Professor (40301246)
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| Co-Investigator(Kenkyū-buntansha) |
KAIDO Masanori Kyoto University, Agronomy, AssiStant professor (20314247)
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| Project Period (FY) |
2005 – 2007
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| Keywords | CSVd / Transgenic plants / Functional RNA / siRNA / Chrysanthemum / Photoperiodism / Viroid / Gene silencing |
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| Research Abstract |
Chrysanthemum is one of the obligative short-day flowering plants. Therefore, usually the flowering of chrysanthemum can be controlled by photoperiod. However, it was noted that 'Piato' plants infected by the CSVd flowered autonomously even under long-day conditions. In this study, we clarified the relationship between CSVd infection and the autonomous flowering of 'Piato' plants regenerated from different-sized dissected shoot apical meristems. Under natural short-day conditions, the flowering of plants regenerated from SAMs containing LPs was one month earlier than plants regenerated from LP-free SAMs. CSVd was detected from these early flowering plants by RT-PCR. On the other hand, CSVd was not detected in plants regenerated from LP-free SAMs. CSVd-infected and -free plants were grown under long-day conditions simulated by night-break lighting at 22: 00-2: 00. All CSVd-infected plants flowered autonomously even under long-day conditions; on the other hand, CSVd-free chrysanthemum pl
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ants maintained their vegetative growth. When the CSVd-free plants were inoculated with CSVd by grafting them to CSVd-infected root stocks, they flowered autonomously even under night-break lighting. In this study, results suggest that CSVd may control the qualitative development process, flowering; that is, it can induce the autonomous flowering of chrysanthemum.
We introduced siRNA expressed vectors to 'I-69-8' plants and produced several transgenic plants. One line introduced by vector1 which has sense and antisence strand of 120bp CSVd sequences and two lines introduced by vector2 having 120bp CSVd sense sequence express a little bit of resistance to CSVd. And time course observation clarified that in these lines CSVd titers increase CSVd after inoculation and then decreases gradually. And one line introduced by vector1 was only partly infected by CSVd in a leaf. So these plants are supposed to have a siRNA produced by the break down by the interaction between infected CSVd molecules and introduced genes. I must check siRNA production in plants and the flowering time of these plants. Less
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