2004 Fiscal Year Final Research Report Summary
Analysis of regulating factor of photosynthesis by two-dimensional fluorescence screening
| Project/Area Number |
14340250
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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
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SONOIKE Kintake The University of Tokyo, Graduate School of Frontier Sciences, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (30226716)
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| Project Period (FY) |
2002 – 2004
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| Keywords | photosynthesis / environmental response / regulating factor / chlorophill fluorescence / pulse modulation / screening / Arabidopsis / T-DNA |
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| Research Abstract |
Although light is indispensable for plants survival, excessive light can lead to produce active oxygen species, giving damage to the photosynthetic apparatus. In order to avoid this damage, plants have evolved multiple mechanisms that down-regulate photosynthetic electron transport upon the shift to high light. To find out the key proteins that regulate the initial activation of photosynthetic electron transport under HL condition, we isolated an Arabidopsis mutant, cfa1 (chlorophyll fluorescence alteration), by the screening based on the kinetics of chlorophyll fluorescence for 12 seconds. Measurement of chlorophyll fluorescence by pulse amplified modulating system (PAM) showed that none of the photosynthetic parameters in the steady state were distinguishable between the cfa1 mutant and WT either under high light condition at 750 μE/m2s (HL) or under growth light condition at 80 μE/m2s (LL). However, time course of non photochemical quenching (NPQ) and photochemical quenching (qP) indicated that induction of NPQ and qP delayed in the cfa1 mutant when exposed to HL compared to those of WT. This phenatypic character was enhanced in the plants grown under higher light condition at 250 μE/m2s, where the mutants grew slower than WT. Interestingly, induction of NPQ and qP of the cfa1 mutant grown under higher light condition at 250 με/m2s delayed even under LL. These results suggest that CFA1 may be involved not only in the initial activation of photosynthetic electron transport upon the shift to HL but also in acclimation to high light. The site of T-DNA insertion was on 5'-UTR of unknown protein having motifs of chloroplast transit peptide and of carboxypeptidase A. Further study of the cfa1 mutant should reveal the regulatory mechanism of the response of electron transport to high light condition.
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