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Department of Plant Biology
University of Minnesota
250 Biological Science Center
1445 Gortner Ave.
St. Paul, MN 55108

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Igor Libourel

Assistant Professor, Department of Plant Biology
Ph.D., University of Oxford, 2004

Metabolic Systems Biology

Contact Information

Mailing Address:

Dr. Igor Libourel
Department of Plant Biology
University of Minnesota
250 Biological Science Center
1445 Gortner Ave.
St. Paul, MN 55108

Research Interests

Marine microalgae account for half of the earth’s photosynthetic activity, and are exposed to environmental changes brought about by global warming. Climate change will affect the marine habitat and alter prevailing selective pressures. Consequently, algae will evolve to adapt to the new conditions. Evolved strains may interact with their surroundings differently, which is relevant to the global environment given their great abundance. Presumably, natural selection optimizes central metabolism to provide metabolic building blocks at the highest possible cost efficiency. Due to strong peer selection, this optimality assumption appears especially apt for organisms such as marine algae. Our research is focused on discovering the design principles of this core metabolism. The picoalgae Ostreococcus is a prevalent genus in the world’s oceans and is used in our lab as a model system. We study the metabolic features of Ostreococcus, and investigate the relationship between metabolic adaptation and the environment.

Ostreococcus

Ostreococcus tauri is the smallest known eukaryote (~1μm), and is considered the most primitive member of the green lineage. It has a very small genome (12.6 Mbp, 10% the size of Arabidopsis) and three species of the genus, O. tauri and O. lucimarinus (see Figure) and RCC809 have been sequenced and annotated. Ostreococcus ecotypes with photosynthetic adaptations to different light levels have been reported in the literature, suggesting that strains with different modes of primary metabolism are readily available. Its simple build (small genome, a single copy mitochondrion and chloroplast, no cell wall or flagellum) makes O. tauri an ideal organism for plant systems biology research.

Systems analysis of metabolism

To test for the existence of inferred metabolic optimalities, the lab uses three complementary approaches where: i) analysis of metabolic optimalities is used to predict and/or incorporate selective pressures in metabolic models; ii) selective pressures are measured by quantifying genetic variability; and iii) metabolic flux analysis is used to experimentally determine the metabolism of Ostreococcus species. The resulting insight is used to validate and improve our ability to predict functionality and evolution of metabolism. By providing a more dynamic description of the population of the world's oceans, our work aims to contribute to the improvement of currently existing climate models. 

Employment

The lab is interested in recruiting a part-time technician and students and/or postdoctoral research assistants. Students and postdoctoral scholars should be keen to participate in an interdisciplinary lab, and have a solid background in mathematics. The lab is particularly interested in postdoctoral scholars experienced in metabolic systems biology or metabolic flux analysis. Please contact me by email if you are interested in joining our lab.

Libourel IGL, Allen DK, Shachar-Hill Y. (submitted) Minimization of Thermodynamic Constraint Weighted Metabolic Adjustment, Biophys. J.

Allen DK; Libourel IGL; Shachar-Hill Y. (2009) "Metabolic Flux Analysis in Plants: Coping with Complexity", Plant Cell Environ. (special issue on Plant Computational Biology).

Libourel IGL, Shachar-Hill Y. (2008) Metabolic Flux Analysis in Plants: From Intelligent Design to Rational Engineering, Ann. Rev. Plant Biol. 59:625–50

*Bethke PC, *Libourel IGL, Aoyama N, Chung YY, Still DW, Jones RL. (2007) The Arabidopsis aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy, Plant Physiol. 143:1173-88 * Authors contributed equally

Libourel IGL, Gehan JP, Shachar-Hill Y. (2007) Design of substrate label for steady state flux measurements in plant systems using the metabolic network of Brassica napus embryos, Phytochemistry 68:2211-1221

Bethke PC, Libourel IGL, Jones RL. (2006) Nitric oxide reduces seed dormancy in Arabidopsis, J. Exp. Bot. 57:517-26

Libourel IGL, van Bodegom PM, Fricker MD, Ratcliffe RG. (2006) Nitrite reduces cytoplasmic acidosis under anoxia, Plant Physiol. 142:1710-7

Libourel IGL, Bethke PC, Michele R, Jones RL. (2006) Nitric oxide gas stimulates germination of dormant Arabidopsis seeds: use of a flow-through apparatus for delivery of nitric oxide Planta, 223:813-820

Bethke PC, Libourel IGL, Reinöhl V, Jones RL. (2006) Sodium nitroprusside, cyanide, nitrite, and nitrate break Arabidopsis seed dormancy in a nitric oxide-dependent manner, Planta 223:805-812

Libourel IGL (2003) The role of nitrate in the root response to anoxia. PhD thesis, University of Oxford, Oxford

Stoimenova M, Libourel IGL, Ratcliffe RG, Kaiser WM. (2003) The role of nitrate reduction in the anoxic metabolism of roots - II. Anoxic metabolism of tobacco roots with or without nitrate reductase activity, Plant and Soil 253:155-67

Book Chapters

Bethke PC, Libourel IGL, Vitecek J, Jones RL (2009) Nitric Oxide and Seed Dormancy and Germination, in Methods in Molecular Biology, ed. AR Kermode, Springer Verlag

Bethke PC, Libourel IGL, Jones RL. (2007) Nitric Oxide in Seed Dormancy and Germination, in Seed Development, Dormancy and Germination, ed. KJ Bradford, H Nonogaki,153-175. Blackwell Publishing Ltd