Poster: Environmental physiology
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P01002: Reduction of plastoquinone in low-light conditions functioned as a signal for high-light adaptation in transplastomic plants -Physiological function of plastoquinone as the redox sensor-
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Presenter: |
Kato, Hideki Contact Presenter |
Authors | Kato, Hideki (A) Yuki, Shinzaki (A) Sayaka, Horiguchi (A) Hiroshi, Yamamoto (A) Minori, Nishioka (A) Akiko, Takase (A) Toshiharu, Hase (B) Amane, Makino (C) Chikahiro, Miyake (A) Ken-Ichi, Tomizawa (A) | | Affiliations: |
(A): Research Institute of Innovative Technology for the Earth (RITE)
(B): Inst. Protein Res., Osaka Univ.
(C): Gard. Sch. Agri. Sci., Tohoku Univ.
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| Web Site: | http://www.rite.or.jp | |
Light is an essential element for plant growth, however, its overabundant can be a harmful factor causing photoinhibition, due to electron-rich induced oxidation-stress. To avoid photoinhibition, plant performs to down-size light-harvesting capacity to lower light absorption efficiency of leaf, and facilitate of active-oxygen scavenging activity. These avoidance responses for high-light adaptation, a sensor plays important role for recognition of photoenvironmental change. And the reduced form of plastoquinone (PQ) is proposed to function as the sensor. Role of the redox change in PQ as the senor has been analyzed in the extreme conditions to distribute leaf photosynthesis rate or plant growth. Then, we produced transplastmoic tobacco plant overexpressing ferredoxin in chloroplasts, to reveal the function of the PQ as the sensor. In transplastomic plant, reduction of PQ was enhanced by ferredoxin-quinone oxidoreductase (FQR), even in the low-light conditions, indicating that transplastomic plants were exposed to mimetic high-light conditions. In those plants, light-harvesting capacity was decreased as observed in low chlorophyll and carotene contents, compared to wild-type. It is also observed that the amount of both D1 protein and NdhH were decreased, suggesting the repression of PQ-reduction, and Cytf was increased, indicating the stimulation of PQ-oxidation. These responses contribute to the removal of excess electron in chloroplasts. From above results, we concluded that the reduced PQ function as a signal for high-light adaptation.
