1992 Fiscal Year Final Research Report Summary
Mechanism of light signal transduction in guard cells of green leaves
| Project/Area Number |
03640570
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
SHIMAZAKI Kenichiro Col. of Gen. Educ. Kyushu Univ. Asso. Prof., 教養部, 助教授 (00124347)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAKI T. Facul. of Tech. Tokai Univ. Asso. Prof., 工学部, 助教授 (70124344)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Stomata / Blue light effect / Calmodulin / Vicia faba L / Guard cells / Proton pump / Protein phosphorylation / ミオシン軽鎖 |
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| Research Abstract |
1 Signal transduction processes in the blue light-dependent proton extrusion by guard cell protoplasts from Vicia faba was investigated using pharmacological tools. Blue light-dependent proton extrusion was inhibited by calmodulin (CaM) antagonists and myosin light chain kinase (MLCK) inhibitors. Other protein kinase inhibitors do not suppress the proton extrusion. The light-dependent stomatal opening in the epidermis of Commelina benghalensis ssp. was suppressed by CaM antagonists and MLCK inhibitors. Furthermore, fusicoccin, a fungal phytotoxin, resumed the proton extrusion and stomatal opening in the presence of these inhibitors. These results suggest that CaM-antagonists and MLCK inhibitors inhibit the signal transduction pathway of blue light response of stomata.
2 Protein phosphorylation and dephosphorylation of guard cell protoplasts in response to light and dark was studied. Several proteins with molecular masses of 42, 40, 34, 32, 26 and 19 kD were phosphorylated. Illumination of the dark-adapted protoplasts with red light caused the dephosphorylation of the 26 kD protein. Several lines of evidence indicates that the 26 KD protein is the light-harvesting chlorophyll a/b protein complex of photosystem II. The light-induced dephosphorylation was inhibited by okadaic acid, an inhibitor of serine/threonie protein phosphatase, suggesting that the dephosphorylation is mediated by type-2A protein phosphatase under the light absorbed by photosystem I.
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