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Dr. Ute Krämer, Head of the Department and Full Professor, Department of Plant Physiology, Ruhr-Universitat Bochum will be speaking at the Danforth Center’s Fall Symposium on Thursday, September 29, 2011.
Ute Krämer is a Professor of Plant Physiology at the University of Bochum/Germany.
Dr. Krämer is a Professor of Plant Physiology at the University of Bochum/Germany since 2009. Trained as a biochemist, she received a D.Phil. as a Rhodes Scholar at the University of Oxford in the United Kingdom for work on the mechanistic basis underlying extreme traits in Arabidopsis relatives and continued her work during a post-doc at Rutgers University in New Jersey. Leading an Independently Funded Group at the Max Planck Institute of Molecular Plant Physiology in Potsdam, Germany, she developed Arabidopsis halleri as a model for comparative genomics of plant adaptation and trace metal homeostasis in plants. She has received the Biofuture Prize of the German Federal Ministry of Education and Research.
Dr. Krämer will be addressing the topic “Metal hyperaccumulation in Arabidopsis halleri – an extreme, complex trait." The in depth presentation will cover how her lab combines evolutionary, molecular and physiological approaches to gain an improved understanding of plant adaptation. Their primary model species, Arabidopsis halleri, is an efficient colonizer of metal-polluted toxic soils and differs from the most closely related species A. lyrata and A. thaliana by the rare physiological traits of heavy metal tolerance and so-called metal hyperaccumulation. Accumulation of leaf concentrations above 10,000 μg g-1 dry biomass zinc and 100 μg g-1 dry biomass cadmium – only known in a handful of plant species – is common among Arabidopsis halleri individuals originating from metal-contaminated as well as from non-contaminated soils containing only background levels of heavy metals. Previously we identified a number of candidate genes employing cross-species comparative transcript profiling. To determine the roles of candidate genes, we use RNA interference in A. halleri as well as heterologous expression in A. thaliana among other approaches. Thus they were able to show that high expression of Heavy Metal ATPase4 (HMA4) is required for Cd hypertolerance and the full extent of Zn hypertolerance, as well as for Zn hyperaccumulation. As a P-type Zn/Cd-pumping ATPase, HMA4 functions in cellular metal export and metal release from the root symplasm into the xylem for subsequent root-to-shoot transport. A combination of BAC sequencing and reporter gene studies showed that high HMA4 transcript levels in A. halleri result from a combination of cis-regulatory mutations and gene copy number expansion when compared to HMA4 of A. lyrata or A. thaliana.
Recent data on intra-specific genetic and phenotypic variation in A. halleri will be discussed from an evolutionary perspective.
In addition, Dr. Sabeeha Merchant, Professor of Biochemistry, Department of Chemistry and Biochemistry, University of California, Los Angeles will be speaking Thursday, September 29, 2011.
Dr. Sabeeha Merchant is a Professor of Biochemistry at the University of California at Los Angeles. Dr. Merchant is a Professor of Biochemistry at the University of California at Los Angeles. She received a Bachelor's degree in Molecular Biology and doctorate in Biochemistry, both from the University of Wisconsin, Madison. During her post-doctoral studies at Harvard, she developed Chlamydomonas as a reference organism for studying trace metal homeostasis in the context of nutrient deficiency. At UCLA since 1987, Merchant has expanded towards a whole genome view of trace element metabolism in algal organelles. Her work in the area of photosynthesis and algal biology has been recognized by multiple awards from UCLA, the ASPB and the NAS.
Dr. Merchant’s presentation will focus on "Ironing out metabolic wrinkles in nutrient deficient ." Ironing out metabolic wrinkles in nutrient deficient Chlamydomonas Iron is an essential nutrient for virtually all forms of life because of its role in bioenergetics processes and oxygen chemistry, and its reduced bioavailability after the great oxidation event limits life. Therefore, most organisms have mechanisms for handling nutritional iron deficiency and their metabolism can acclimate to this situation. Dr. Merchant used growth, classical visual symptoms of iron-deficiency and sentinel gene expression to define 4 physiological “states” of iron nutrition. Transcriptome and proteome profiles of these states indicate the importance of plastid anti-oxidant pathways for handling iron imbalance, reveal previously uncharacterized transporters and novel enzymes that are conserved throughout the plant kingdom.
To learn more about our 13th Annual Fall Symposium visit, http://www.danforthcenter.org/fall_symposium/. For the most up-to-date information, please follow us on Facebook & Twitter #FallSymposiumSTL.
| plant adaptationphysiological traitsphenotypic variationnutrientiron deficiencyFall symposuimChlamydomonasArabidopsis