Journal article
Identification of the ADP-glucose pyrophosphorylase isoforms essential for starch synthesis in the leaf and seed endosperm of rice (Oryza sativa L.)
Plant molecular biology, Vol.65(4), pp.531-546
11/2007
Handle:
https://hdl.handle.net/2376/105529
PMID: 17406793
Abstract
ADP-glucose pyrophosphorylase (AGP) catalyzes the first committed step of starch biosynthesis in higher plants. To identify AGP isoforms essential for this biosynthetic process in sink and source tissues of rice plants, we analyzed the rice AGP gene family which consists of two genes, OsAGPS1 and OsAGPS2, encoding small subunits (SSU) and four genes, OsAGPL1, OsAGPL2, OsAGPL3 and OsAGPL4, encoding large subunits (LSU) of this enzyme heterotetrameric complex. Subcellular localization studies using green fluorescent protein (GFP) fusion constructs indicate that OsAGPS2a, the product of the leaf-preferential transcript of OsAGPS2, and OsAGPS1, OsAGPL1, OsAGPL3, and OsAGPL4 are plastid-targeted isoforms. In contrast, two isoforms, SSU OsAGPS2b which is a product of a seed-specific transcript of OsAGPS2, and LSU OsAGPL2, are localized in the cytosol. Analysis of osagps2 and osagpl2 mutants revealed that a lesion of one of the two cytosolic isoforms, OsAGPL2 and OsAGPS2b, causes a shrunken endosperm due to a remarkable reduction in starch synthesis. In leaves, however, only the osagps2 mutant appears to severely reduce the transitory starch content. Interestingly, the osagps2 mutant was indistinguishable from wild type during vegetative plant growth. Western blot analysis of the osagp mutants and wild type plants demonstrated that OsAGPS2a is an SSU isoform mainly present in leaves, and that OsAGPS2b and OsAGPL2 are the major SSU and LSU isoforms, respectively, in the endosperm. Finally, we propose a spatiotemporal complex model of OsAGP SSU and LSU isoforms in leaves and in developing endosperm of rice plants.
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- Title
- Identification of the ADP-glucose pyrophosphorylase isoforms essential for starch synthesis in the leaf and seed endosperm of rice (Oryza sativa L.)
- Creators
- Sang-Kyu Lee - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaSeon-Kap Hwang - Institute of Biological Chemistry Washington State University Pullman WA 99164-6340 USAMuho Han - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaJoon-Seob Eom - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaHong-Gyu Kang - BK21 Life Sciences and Biotechnology Kyungpook National University Daegu 702-701 KoreaYulyi Han - Department of Biological Sciences Myongji University Yongin 449-728 KoreaSang-Bong Choi - Department of Biological Sciences Myongji University Yongin 449-728 KoreaMan-Ho Cho - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaSeong Bhoo - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaGynheung An - National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences Pohang University of Science and Technology Pohang 790-784 KoreaTae-Ryong Hahn - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 KoreaThomas Okita - Institute of Biological Chemistry Washington State University Pullman WA 99164-6340 USAJong-Seong Jeon - Graduate School of Biotechnology & Plant Metabolism Research Center Kyung Hee University Yongin 446-701 Korea
- Contributors
- Gynheung An (Editor)Hei Leung (Editor)Takuji Sasaki (Editor)Qifa Zhang (Editor)
- Publication Details
- Plant molecular biology, Vol.65(4), pp.531-546
- Academic Unit
- Institute of Biological Chemistry
- Publisher
- Springer Netherlands; Dordrecht
- Identifiers
- 99900546535001842
- Language
- English
- Resource Type
- Journal article