| Budget Amount *help |
¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2014: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2013: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Outline of Final Research Achievements |
Respiratory electron transport has two ubiquinol-oxidizing pathways, the cytochrome pathway (CP) and the alternative oxidase (AOX). AOX is energetically wasteful but may alleviate photosystem II (PSII) photoinhibition. However, its mechanism remains unknown. We used Arabidopsis aox1a mutants lacking AOX and studied the mutation’s effects on photoinhibition by measuring the decrease in the maximum quantum yield of PSII (Fv/Fm) after high light (HL) exposure. Since CP compensates for the lack of AOX, we monitored the extent of photoinhibition under conditions where CP activity is partially inhibited by antimycin A. When leaves were exposed to HL, the decline in Fv/Fm was faster in the aox1a mutants, but under conditions where photorespiration was suppressed, the decline in Fv/Fm was suppressed in the aox1a mutants, but not in the wild type. Our results demonstrate that the lack of AOX causes an acceleration of PSII photoinhibition in relation to the photorespiratory pathway.
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