6 results on '"Zeeman, Samuel C."'
Search Results
2. The evolution of functional complexity within the β-amylase gene family in land plants
- Author
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Thalmann, Matthias, Coiro, Mario, Meier, Tiago, Wicker, Thomas, Zeeman, Samuel C., and Santelia, Diana
- Published
- 2019
- Full Text
- View/download PDF
3. The evolution of functional complexity within the -amylase gene family in land plants
- Author
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Thalmann, Matthias, Coiro, Mario, Meier, Tiago, Wicker, Thomas, Zeeman, Samuel C., and Santelia, Diana
- Subjects
Green plants ,Phylogenetic analysis ,Gene duplication ,Functional diversification ,food and beverages ,Starch ,β-Amylase - Abstract
Background β-Amylases (BAMs) are a multigene family of glucan hydrolytic enzymes playing a key role not only for plant biology but also for many industrial applications, such as the malting process in the brewing and distilling industries. BAMs have been extensively studied in Arabidopsis thaliana where they show a surprising level of complexity in terms of specialization within the different isoforms as well as regulatory functions played by at least three catalytically inactive members. Despite the importance of BAMs and the fact that multiple BAM proteins are also present in other angiosperms, little is known about their phylogenetic history or functional relationship. Results Here, we examined 961 β-amylase sequences from 136 different algae and land plant species, including 66 sequenced genomes and many transcriptomes. The extraordinary number and the diversity of organisms examined allowed us to reconstruct the main patterns of β-amylase evolution in land plants. We identified eight distinct clades in angiosperms, which results from extensive gene duplications and sub- or neo-functionalization. We discovered a novel clade of BAM, absent in Arabidopsis, which we called BAM10. BAM10 emerged before the radiation of seed plants and has the feature of an inactive enzyme. Furthermore, we report that BAM4 – an important protein regulating Arabidopsis starch metabolism – is absent in many relevant starch-accumulating crop species, suggesting that starch degradation may be differently regulated between species. Conclusions BAM proteins originated sometime more than 400 million years ago and expanded together with the differentiation of plants into organisms of increasing complexity. Our phylogenetic analyses provide essential insights for future functional studies of this important class of storage glucan hydrolases and regulatory proteins., BMC Evolutionary Biology, 19, ISSN:1471-2148
- Published
- 2019
4. A whole-plant chamber system for parallel gas exchange measurements of Arabidopsis and other herbaceous species.
- Author
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Kölling, Katharina, George, Gavin M., Künzli, Roland, Flütsch, Patrick, and Zeeman, Samuel C.
- Subjects
GAS exchange in plants ,HERBACEOUS plants ,CARBON dioxide ,PLANT biomass ,ARABIDOPSIS - Abstract
Background: Photosynthetic assimilation of carbon is a defining feature of the plant kingdom. The fixation of large amounts of carbon dioxide supports the synthesis of carbohydrates, which make up the bulk of plant biomass. Exact measurements of carbon assimilation rates are therefore crucial due to their impact on the plants metabolism, growth and reproductive success. Commercially available single-leaf cuvettes allow the detailed analysis of many photosynthetic parameters, including gas exchange, of a selected leaf area. However, these cuvettes can be difficult to use with small herbaceous plants such as Arabidopsis thaliana or plants having delicate or textured leaves. Furthermore, data from single leaves can be difficult to scale-up for a plant shoot with a complex architecture and tissues in different physiological states. Therefore, we constructed a versatile system-EGES-1-to simultaneously measure gas exchange in the whole shoots of multiple individual plants. Our system was designed to be able record data continuously over several days. Results: The EGES-1 system yielded comparable measurements for eight plants for up to 6 days in stable, physiologically realistic conditions. The chambers seals have negligible permeability to carbon dioxide and the system is designed so as to detect any bulk-flow air leaks. We show that the system can be used to monitor plant responses to changing environmental conditions, such as changes in illumination or stress treatments, and to compare plants with phenotypically severe mutations. By incorporating interchangeable lids, the system could be used to measure photosynthetic gas exchange in several genera such as Arabidopsis, Nicotiana, Pisum, Lotus and Mesembryanthemum. Conclusion: EGES-1 can be introduced into a variety of growth facilities and measure gas exchange in the shoots diverse plant species grown in different growth media. It is ideal for comparing photosynthetic carbon assimilation of wild-type and mutant plants and/or plants undergoing selected experimental treatments. The system can deliver valuable data for whole-plant growth studies and help understanding mutant phenotypes. Overall, the EGES-1 is complementary to the readily-available single leaf systems that focus more on the photosynthetic process in within the leaf lamina. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
5. A device for single leaf labelling with CO2 isotopes to study carbon allocation and partitioning in Arabidopsis thaliana.
- Author
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Kölling, Katharina, Müller, Antonia, Flütsch, Patrick, and Zeeman, Samuel C.
- Subjects
PLANT biomass ,CARBOHYDRATES ,ARABIDOPSIS thaliana ,PLANT growth ,PHOTOBIOLOGY - Abstract
Background Plant biomass consists primarily of carbohydrates derived from photosynthesis. Monitoring the assimilation of carbon via the Calvin-Benson cycle and its subsequent utilisation is fundamental to understanding plant growth. The use of stable and radioactive carbon isotopes, supplied to plants as CO
2 , allows the measurement of fluxes through the intermediates of primary photosynthetic metabolism, long-distance transport of sugars in the vasculature, and the synthesis of structural and storage components. Results Here we describe the design of a system for supplying isotopically labelled CO2 to single leaves of Arabidopsis thaliana. We demonstrate that the system works well using short pulses of14 CO2 and that it can be used to produce robust qualitative and quantitative data about carbon export from source leaves to the sink tissues, such as the developing leaves and the roots. Time course experiments show the dynamics of carbon partitioning between storage as starch, local production of biomass, and export of carbon to sink tissues. Conclusion This isotope labelling method is relatively simple to establish and inexpensive to perform. Our use of14 CO2 helps establish the temporal and spatial allocation of assimilated carbon during plant growth, delivering data complementary to those obtained in recent studies using13 CO2 and MS-based metabolomics techniques. However, we emphasise that this labelling device could also be used effectively in combination with13 CO2 and MS-based techniques. [ABSTRACT FROM AUTHOR]- Published
- 2013
- Full Text
- View/download PDF
6. A device for single leaf labelling with CO2 isotopes to study carbon allocation and partitioning in Arabidopsis thaliana.
- Author
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Kölling K, Müller A, Flütsch P, and Zeeman SC
- Abstract
Background: Plant biomass consists primarily of carbohydrates derived from photosynthesis. Monitoring the assimilation of carbon via the Calvin-Benson cycle and its subsequent utilisation is fundamental to understanding plant growth. The use of stable and radioactive carbon isotopes, supplied to plants as CO2, allows the measurement of fluxes through the intermediates of primary photosynthetic metabolism, long-distance transport of sugars in the vasculature, and the synthesis of structural and storage components., Results: Here we describe the design of a system for supplying isotopically labelled CO2 to single leaves of Arabidopsis thaliana. We demonstrate that the system works well using short pulses of 14CO2 and that it can be used to produce robust qualitative and quantitative data about carbon export from source leaves to the sink tissues, such as the developing leaves and the roots. Time course experiments show the dynamics of carbon partitioning between storage as starch, local production of biomass, and export of carbon to sink tissues., Conclusion: This isotope labelling method is relatively simple to establish and inexpensive to perform. Our use of 14CO2 helps establish the temporal and spatial allocation of assimilated carbon during plant growth, delivering data complementary to those obtained in recent studies using 13CO2 and MS-based metabolomics techniques. However, we emphasise that this labelling device could also be used effectively in combination with 13CO2 and MS-based techniques.
- Published
- 2013
- Full Text
- View/download PDF
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