| iCal Calendar Event Reminder | 16:00 - 17:30 | Thursday, November 13, 2008 |
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| Event Text: | Prof. Dr. Christoph Peterhaensel Leibniz - University Hannover Institute of Botany Hannover GERMANY |
| Event Date: | Thursday, November 13, 2008 |
| Event Time: | 16:00 - 17:30 |
| Popup Text: | ???Glycolate metabolism in higher plants: An outstanding target for crop improvement??? ABSTRACT Rashad Kebeish, Markus Niessen, Stephanie Klaus, Jens Gruber, Sonja Toepsch, Christoph Peterhaensel Leibniz University Hannover, Institute of Botany, 30419 Hannover, Germany, cp@botanik.uni-hannover.de In C3 plants, RUBISCO catalyses both the carboxylation and the oxygenation of Ribulose-1,5-bisphosphate. Carboxylation accounts for net CO2 fixation whereas oxygenation leads to synthesis of glycolate that has to be recycled in the photorespiratory salvage pathway. NH3 and CO2 are lost in this cycle and have to be refixed. These losses limit plant productivity under many growth conditions. By step-wise transformation with five chloroplast-targeted genes encoding glycolate dehydrogenase, glyoxylate carboligase and tartronic semialdehyde reductase, we installed a bacterial pa thway for the conversion of glycolate, the primary product of photorespiration, to glycerate in the chloroplasts of Arabidopsis thaliana. This reduced, but did not eliminate, metabolite flow through photorespiration. Chloroplastic CO2 concentration in the vicinity of RUBISCO and net CO2 fixation were enhanced compared to control lines. Superior physiological parameters correlated with enhanced growth of shoots and roots. We will present data on the further physiological characterization of transgenic lines including comparative transcriptome analyses and metabolic profiling. Possibilities for simplifying the complex genetic approach with the aim to facilitate the application in crop improvement will be discussed. Furthermore, new insights into supplementary endogenous pathways for glycolate metabolism beside ???textbook??? photorespiration will be provided. Key references: Kebeish R, Niessen M, Thiruveedhi K, Bari R, Hirsch HJ, Rosenkranz R, Stable r N, Schonfeld B, Kreuzaler F, Peterhansel C (2007) Chloroplastic photorespiratory bypass increases photosynthesis and biomass production in Arabidopsis thaliana. Nature Biotechnology, 25: 593-599. Niessen M, Thiruveedhi K, Rosenkranz R, Kebeish R, Hirsch HJ, Kreuzaler F, and Peterh??nsel C (2007) Mitochondrial glycolate oxidation contributes to photorespiration in higher plants. Journal of Experimental Botany, 58: 2709-2715. |