| Project/Area Number |
62304004
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | Hokkaido University |
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Principal Investigator |
YOSHIDA Shizuo The Institute of Low Temperature Science, Hokkaido Univ. Prof., 低温科学研究所, 教授 (90001651)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUO Tomoaki Dept. Agriculture, Kagoshima Univ. Res. Assoc., 農学部, 助手 (90041673)
SEKIYA Jiro Dept. Agriculture, Okayama Univ. Assoc.Prof., 農学部, 助教授 (10035123)
MURATA Norio Institute of Basic Biology, Prof., 基礎生物学研究所, 教授 (90011569)
SAKATA Toru Dept. Science and Technology, Keio Univ. Prof., 理工学部, 教授 (10051020)
ITO Sisuke Dept. Agricultural Chemistry, Obihiro Univ. Agriculture and Veterinary Medicine,, 畜産学部, 教授 (30003099)
菅原 康剛 埼玉大学, 理工学部, 助教授 (70114212)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥17,500,000 (Direct Cost: ¥17,500,000)
Fiscal Year 1989: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1988: ¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1987: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | Mechanisms of chilling injury / Mechanisms of freezing injury / Phase transition of membrane lipids / Chilling injury and tonoplasts / Low temperature and tonoplast proton pumps / Glycerol-3-phosphate acyltransferase / Purification of enzymes and cDNA cloning / Tonoplast H^+-ATPase and H^+-PPase / 飽和極性脂質分子種 / 液胞膜プロトン輸送の温度依存性 / 低温慣化の機構と細胞膜 / 低温傷害 / 凍結傷害 / 飽和脂質分子種 / 液胞とH^+-ATPase / スフィンゴ糖脂質 / 電子顕微鏡 / ^<31>P-NMR / 相転移 / ^<31>PーNMR / H^+ーATPase / スフィンゴ脂質 / 脂質合成酵素 |
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| Research Abstract |
Experimental results obtained through this Research Project are summarized as follows: 1) Molecular mechanisms of chilling injury. Following two factors were determined to be primary important for chilling injury in plant cells. First, a) a dysfunction of chloroplasts due to a low temperature-induced phase separation of disaturated molecular species of phosphatidylglycerol in the lipid bilayers. The correlation between the content of disaturated phosphatidylglycerol and the chilling sensitivity of plants was established both in hevaceous and woody plant species. The phase separation of disaturated phosphatoidylglycerol in intact membrane systems under low temperatures was determined by an analysis of msec delayed fluorescence.The key enzyme which controls the synthesis of the disaturated molecular species of phosphatidylglycerol was purified from chilling sensitive squash cotyledons and the CDNA was successfully cloned. Second, b) a disturbance of an iconic environment of cytoplasms du
… More
e to a low temperature-induced dysfunction of tonoplast proton transports. In mung bean cells, the tonoplast H^+-ATPase is impaired by a relatively short time of chilling in vivo, giving rise to an acidification of the cytoplasms. Two types of the proton transporting enzymes, i.e., H^+-ATPase and H^+-PPase, were purified from mung bean seedlings and characterized. The low temperature-induced inactivation of the H^+-ATPase is found to be related to a specific release of 57, 68 and 32 kDa subunits. 2) Mechanisms of freezing injury. Based on electronmicroscopic studies, it was confirmed that a freeze-induced ultrastructural changes in plasma membranes is primary important factor for cell injury. Upon a lethal freezing of cells, an aggegation of intramebranous particles and a formation of particle-free area, and a formation of Hexagonal THY phase structure were observed in plasma membranes specifically related to chill injury. However, these ultrastructural changes seemed to be dependent on plant species and the cell types, suggesting a diversity in the mechanisms of freezing injury. In sold acclimation of plants, a molecular rearrangement of plasma membranes, which includes qualitative changes in membrane proteins and enrichment of unsaturated phospholipids, is considered to play an important role in stabilization of plasma membranes against freezing stress.
These results may provide a basis for molecularbiological approaches to the mechanisms of chilling injury and freezing injury in plants in future. Less
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