Agricultural biotechnology; Arabidopsis thaliana; Starch metabolism; Proteomics; Molecular genetics; Starch crops
Strydom L, Jewell J, Meier Michael, George Gavin M, Pfister Barbara, Zeeman Samuel C, Kossmann Jens, Lloyd James R. (2017), Analysis of genes involved in glycogen degradation in Escherichia coli, in FEMS Microbiology Letters
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Seung David, Boudet Julien, Monroe Jonathan, Schreier Tina B, David Laure C, Abt Melanie, Lu Kuan-Jen, Zanella Martina, Zeeman Samuel C (2017), Homologs of PROTEIN TARGETING TO STARCH Control Starch Granule Initiation in Arabidopsis Leaves, in Plant Cell
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Feike Doreen, Seung David, Graf Alex, Bischof Sylvain, Ellick Tamaryn, Coiro Mario, Soyk Sebastian, Eicke Simona, Mettler-Altmann Tabea, Lu Kuan-Jen, Trick Martin, Zeeman Samuel C, Smith Alison M (2016), The starch granule-associated protein EARLY STARVATION1 (ESV1) is required for the control of starch degradation in Arabidopsis thaliana leaves, in Plant Cell
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Seung David, Soyk Sebastian, Coiro Mario, Maier Benjamin A, Eicke Simona, Zeeman Samuel C (2015), PROTEIN TARGETING TO STARCH Is Required for Localising GRANULE-BOUND STARCH SYNTHASE to Starch Granules and for Normal Amylose Synthesis in Arabidopsis, in PLOS Biology
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Lloyd James R, Kossmann J (2015), Transitory and storage starch metabolism: Two sides of the same coin?, in Current Opinions in Biotechnology
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George Gavin M, Ruckle Michael, Lloyd James R (2015), Virus induced gene silencing as a scalable tool to, in Mysore KS and Senthil-Kumar M (ed.), Springer Science, New York, 243-253.
George Gavin M, Ruckle Michael, Lloyd James R (2015), Virus induced gene silencing as a scalable tool to Study Drought Tolerance in Plants, in Mysore KS and Senthil-Kumar M (ed.), 243-253.
Society relies on the carbohydrates (sugars and starches) produced and stored by plants. In addition to their nutritive value, extracted carbohydrates serve as raw materials in industry. Increasingly, both starch and sugars are used as feedstocks for the production of biofuels, a necessary component of our future sources of renewable energy. The work proposed here aims to discover novel protein factors that control how much and in what form carbohydrates are stored. Starch is the major plant storage carbohydrate, which accumulates in seeds, roots or tubers of the crop plants that form the basis of human nutrition. Increasing the yields of starch crops and modifying the properties of starch are important biotechnological goals. Therefore, we will focus on starch in this work.Although most plants store starch, its metabolism is not fully understood. Starch is composed of glucose polymerised into linear and branched glucans that assemble as massive insoluble granules. Unanswered questions surround 1) the initiation of starch granules - what controls their number and form? This is important as granule size has an impact on properties and end use, and may also limit starch production. 2) The structure of the constituent polymers and how they form insoluble, semi-crystalline structures - how do enzymes working on a soluble substrate generate a crystalline product? Starch granules cannot be generated in a test tube and how the crystallisation process occurs in vivo is unknown. It may involve structural and/or binding proteins in addition to the biosynthetic enzymes. 3) How is starch amount controlled? This is a key question if we are to increase the starch content of plants. Some control lies at the level of substrate supply, but additional control is likely applied during biosynthesis at the granule surface. We will take a new approach to search for previously unidentified protein factors that control these processes.This new proposal has three parts. The first part describes research using proteomics to identify previously uncharacterised starch granule-bound proteins involved in starch biosynthesis. Through preparatory work and external collaborations, we have obtained the biological materials and demonstrated that we have the technological expertise to do this. The second part uses molecular-genetic and biochemical approaches, in which our labs have longstanding expertise, to analyse the functions of the newly identified proteins. This will be done both in vivo and in vitro, using the Arabidopsis thaliana and Escherichia coli model systems. The third part will apply useful knowledge to alter the starch properties in potato and cassava - important European and African starch crops. For this applied approach, our groups have expertise in house from the first phase and bridging funding in 2012/2013. Furthermore, we have fruitful interactions with other researchers, including experts on cassava (Prof C. Rey, University of the Witwatersrand, and Dr H. Vanderschuren, ETH Zurich) within the Swiss-South African Joint Research Programme (SSAJRP).In the first phase of the SSAJRP, we built a highly effective collaboration between our labs with a series of meetings, staff exchanges, joint research and joint publications. By analysing proteins that determine the amount of phosphate covalently bound to starch, we demonstrated that our approaches can provide valuable knowledge (patented together with Bayer CropScience). This knowledge will enable the future improvement of starch crops. Thus, we anticipate that the fundamental discoveries made during this joint research programme will have far-reaching implications in terms of agriculture and the production of raw materials for renewable clean green technologies.