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| Home > Publications database > Toward understanding the regulation of carotenoid turnover in plants |
| Conference Presentation (Other) | FZJ-2019-04763 |
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2019
Abstract: Progress in plant carotenoid research has brought the scientific community genetic and molecular tools to manipulate carotenoid composition and accumulation in model plants and crops. However, the outcome of such manipulation often remains unpredictable due to many “unknowns” in feedback regulation, protein modification and interaction, or compartmentalization. Unravelling the mechanisms that control flux, partitioning and sequestration in carotenoid biosynthesis and degradation pathways necessitates, among other things, turnover analysis of pathway intermediates and products. Isotopic labelling has been a powerful tool for investigation of metabolic pathways in cells and plants. Photosynthetic CO2 fixation enables convenient incorporation of carbon isotopes in various metabolites under various conditions. While incorporation can be observed within seconds to minutes in and around primary metabolism, it can take hours to days for specialized metabolism, including that of carotenoids and apocarotenoids in photosynthetic and non-photosynthetic organs. Despite high sensitivity of detection, radioactive 14C is difficult to quantify at the molecular level and experiments inevitably generate radioactive waste. Here, we present whole-plant 13CO2 labelling systems combined with LC-MS and FTICR-MS analysis to study carotenoid turnover. Two experiments were conducted to test the applicability of the method. In the first experiment, a walk-in climate chamber was used to obtain 13C-labelled peppermint plants. Subsequently, changes in carotenoid isotopologue composition were monitored in leaves of these plants in ambient air. In the second experiment, Arabidopsis plants grown in ambient air were transferred to a small 13CO2 labelling chamber to analyze 13C incorporation in leaf pigments for up to seven days. The mass spectra of carotenoids obtained from the two experiments showed similar patterns of isotopologue peaks, indicating that the method is compatible with pulse-chase labelling experiments in both directions (13CO2/12CO2 and 12CO2/13CO2). This approach opens up new possibilities to elucidate the regulation of carotenoid metabolism in plants.
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