2006 Fiscal Year Final Research Report Summary
Translocation of inorganic phosphate by membrane transport and vascular bundle system.
| Project/Area Number |
16370024
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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 |
植物生理・分子
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| Research Institution | Kobe University |
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Principal Investigator |
MIMURA Tetsuro Kobe University, Faculty of Science, Professor, 理学部, 教授 (20174120)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAKI Hidehiro Kobe University, Faculty of Science, Associate Professor, 理学部, 助教授 (80324979)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Inorganic phosphate / Translocation / Membrane transport / Arabidopsis / Vascular Bundle / Source-Sink relationship / Barlev / Egeria |
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| Research Abstract |
Inorganic phosphate (Pi) is one of essential elements of plant nutrition. It is well-known that Pi is translocated between tissues dependent on source-sink relationship. In the present study, we have analyzed a molecular mechanism of Pitranslocation between tissues. Using Arabidopsis plants, we found source or sink-specific gene expression. Arabidopsis plants which is defective of those genes showed the suppression of Pi translocation. Furthermore, we developed a new method to isolate living mesophyll cells and vascular bundle in order to analyze how Pi is distributed from vascular bundle to mesophyll cells. To study intracellular compartmentation of Pi, we measured Pi uptake activity of vacuole and conducted proteome analysis of the vacuolar membrane proteins using isolated vacuoles from Arabidopsis suspension cultured cells. We found that under Pi deficiency, vacuolar Pi uptake activity was activated by the activation of
H^+ transporting pumps.
Using barley (Hordeum vulgare), we analyzed ion distribution of a single leaf. Although K^+ and NO_3・levels are high at the bottom of leaf and low at the tip of leaf, Pi equally distributed along the leaf. In hydathode, Pi was activelyre-absorbed and translocated to whole plant tissue.
At last, to analyze Pi transport and translocation of plants in nature, we measured Pi uptake activity of an aquatic plant Egeria densa. In Egeria, a part of Pi was taken up from the soil and transported to leaves in the lake water and some Pi was also taken up from lake water directly. We identified a molecule involving Pi uptake in Egeria leaves.
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