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  • Functional incorporation of sorghum small subunit increases the catalytic turnover rate of Rubisco in transgenic rice.

    Author(s) : Ishikawa, C.Hatanaka, T.Misoo, S.Miyake, C.Fukayama, H.

    Author Affiliation : Laboratory of Crop Science, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan.

    Author Email : fukayama@people.kobe-u.ac.jp

    Journal article : Plant Physiology 2011 Vol.156 No.3 pp.1603-1611 ref.40

    Abstract : Rubisco limits photosynthetic CO2 fixation because of its low catalytic turnover rate (kcat) and competing oxygenase reaction. Previous attempts to improve the catalytic efficiency of Rubisco by genetic engineeringgenetic engineeringSubject Category: Techniques, Methodologies and Equipment
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    have gained little progress. Here we demonstrate that the introduction of the small subunit (RbcS) of high kcat Rubisco from the C4 plant sorghum (Sorghum bicolorsorghum bicolorSubject Category: Organism Names
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    ) significantly enhances kcat of Rubisco in transgenic ricericeSubject Category: Commodities and Products
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    (Oryza sativaoryza sativaSubject Category: Organism Names
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    ). Three independent transgenic lines expressed sorghum RbcS at a high level, accounting for 30%, 44%, and 79% of the total RbcS. Rubisco was likely present as a chimera of sorghum and rice RbcS, and showed 1.32- to 1.50-fold higher kcat than in nontransgenic rice. Rubisco from transgenic lines showed a higher Km for CO2 and slightly lower specificity for CO2 than nontransgenic controls. These results suggest that Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco. Rubisco content in transgenic lines was significantly increased over wild-type levels but Rubisco activation was slightly decreased. The expression of sorghum RbcS did not affect CO2 assimilation rates under a range of CO2 partial pressures. The Jmax/Vcmax ratio was significantly lower in transgenic line compared to the nontransgenic plants. These observations suggest that the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice. Although the photosynthetic rate was not enhanced, the strategy presented here opens the way to engineering Rubisco for improvement of photosynthesisphotosynthesisSubject Category: Natural Processes
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    and productivity in the future.

    ISSN : 0032-0889

    DOI : 10.1104/pp.111.177030

    Record Number : 20113240527

    Publisher : American Society of Plant Biologists

    Location of publication : Rockville

    Country of publication : USA

    Language of text : English

    Indexing terms for this abstract:

    Organism descriptor(s) : OryzaoryzaSubject Category: Organism Names
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    , Oryza sativaoryza sativaSubject Category: Organism Names
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    , plantsplantsSubject Category: Organism Names
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    , Sorghum bicolorsorghum bicolorSubject Category: Organism Names
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    Descriptor(s) : electron transferelectron transferSubject Category: Miscellaneous
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    , enzymesenzymesSubject Category: Chemicals and Chemical Groups
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    , genetic engineeringgenetic engineeringSubject Category: Techniques, Methodologies and Equipment
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    , genetic transformationgenetic transformationSubject Category: Techniques, Methodologies and Equipment
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    , genetically engineered organismsgenetically engineered organismsSubject Category: Organism Groups
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    , oxygenasesoxygenasesSubject Category: Chemicals and Chemical Groups
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    , photosynthesisphotosynthesisSubject Category: Natural Processes
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    , ricericeSubject Category: Commodities and Products
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    , sweet sorghumsweet sorghumSubject Category: Commodities and Products
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    , transgenic plantstransgenic plantsSubject Category: Organism Groups
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    Identifier(s) : carbon assimilation, carbon dioxide fixation, electron flow, electron transport, genetic manipulation, genetically engineered plants, genetically modified organisms, genetically modified plants, GEOs, GMOs, paddy, sugar sorghum, transgenic organisms

    Broader term(s) : PoaceaepoaceaeSubject Category: Organism Names
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    , PoalespoalesSubject Category: Organism Names
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    , commelinidscommelinidsSubject Category: Organism Names
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    , monocotyledonsmonocotyledonsSubject Category: Organism Names
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    , angiospermsangiospermsSubject Category: Organism Names
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    , SpermatophytaspermatophytaSubject Category: Organism Names
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    , plantsplantsSubject Category: Organism Names
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    , eukaryoteseukaryotesSubject Category: Organism Names
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    , OryzaoryzaSubject Category: Organism Names
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    , SorghumsorghumSubject Category: Organism Names
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