Modulation von Biosynthese und Metabolismus der Cytokinine bei Pflanzen
Zusammenfassung der Projektergebnisse
For the moss Physcomitrella patens we collected evidence suggesting that in this model organism the plant hormones cytokinins (isopentenyl-derivatives of adenine), in contrast to seed plants, originate exclusively from tRNA degradation. This conclusion was drawn from database searches for cytokinin biosynthetic genes, which revealed only tRNA-isopentenyltransferases (IPTs) and no adenylate-IPTs. PplPTI was proved to encode for a functional tRNA-IPT by means of functional complementation in Saccharomyces cerevisiae (Yevdakova and Schwartzenberg 2007, Planta 226: 683-695). Cytokinin profiling measurements (Schwartzenberg et al. 2007, Plant Physiol. 145: 786-800), PpIPT1-expression analyses and cytokinin distribution in tRNA supported the important role of tRNa for cytokinin biogenesis in Physcomitrella (Yevdakova et al. 2008, J. Plant Growth Regul., in press). We therefore assume that in early steps of land plant evolution the isopentenylation of tRNA, catalysed by tRNA-IPTs, took over the function of providing precursors for free cytokinins acting as plant hormones. This tRNA-IPT mediated pathway of cytokinin biosynthesis was preserved during the evolution of seed plants, however seed plants additionally developed the de novo synthesis of free cytokinins via isopentenylation of the adenylates ADP/ATP. Further studies elucidating details of tRNA mediated cytokinin biosynthesis are currently carried out.
Projektbezogene Publikationen (Auswahl)
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Modification of cytokinin metabolism in Physcomitrella. Poster, Botanikertagung, Freiburg, 22. - 27. Sept. (2002)
Fernández Núnez M., P. Schulz, K. v. Schwartzenberg
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Molecular physiology of cytokinin metabolism in the moss Physcomitrella. Vortrag, Akademie der Wissenschaftern der Tschechichen Republik, Inst. f. Experimental Botany, Prag, 20. Mai (2003)
Schwartzenberg v. K.
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Physcomitrella patens „Low Cytokinin Transformants" - down regulation of endogenous cytokinin content wa cytokinin oxidase overexpression. Moss 2003, The Annual International Conference for Moss Experimental Research, St. Louis, Missouri, Poster, 7.-10. Sept. (2003)
Fernández Núnez M, N. Yevdakova, P. Schulz, V. Motyka, O. Novak, K. v. Schwartzenberg
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Physcomitrella releases a tetracyclic diterpene into culture medium and atmosphere. Moss 2003, The Annual International Conference for Moss Experimental Research, St. Louis, Missouri, 7. - 10. Sept. (2003)
Schwartzenberg v. K., W. Schultze, H. Kassner
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"Low cytokinin transformants" down regulation of endogenous cytokinin content via cytokinin oxidase overexpression. Vortrag (Mitautor), Forschungstage, Fachbereich Biologie Universität Hamburg, Okt. (2004)
Fernández Núnez M., K. v. Schwartzenberg
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Cytokinin metabolic changes after CKX-overexpression in Physcomitrella. Poster, Botanikertagung, Braunschweig, 5.-10. Sept. (2004)
Blaschke H., M. Fernandez Nunez, V. Motyka, O. Novak, K. v. Schwartzenberg
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Cytokinin metabolism in the moss Physcomitrella patens. Vortrag, Institut Biology II, University of Waterloo, Canada, 27. Okt. (2004)
Schwartzenberg v. K.
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Identification of putative cytokinin biosynthetic genes from the moss Physcomitrella. Poster, Botanikertagung, Braunschweig, 5.-10. Sept. (2004)
Yevdakova N., K. v. Schwartzenberg
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On the molecular physiology of cytokinin metabolism in the moss Physcomitrella. Vortrag, Cytokinin Meeting, Berlin, 10. Juli (2004)
Schwartzenberg v. K.
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Studies of Cytokinin Biosynthetic Genes from Physcomitrella. Poster, Moss 2004, Freiburg , 12.-15. Sept. (2004)
Yevdakova N., K. v. Schwartzenberg
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The moss Physcomitrella releases a tetracyclic diterpene into culture medium and atmospere. Poster, Botanikertagung Braunschweig, 6.-10. Sept. (2004)
Schwartzenberg v. K., W. Schultze, H. Kassner
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Cytokinin metabolism in the moss Physcomitrella. Vortrag, Palacky University, Laboratory of Plant Growrth Regulators, Olomouc, Tschechische Republik, 27. Juli (2005)
Schwartzenberg v. K.
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Effects of altered cytokinin biosynthesis and metabolism in Physcomitrella. Vortrag, Moss 2005, The Annual Intemational Conference for Moss Experimental Research, Mendel Center, Brno, Tschechische Republik, 23. - 26. Juli (2005)
Schwartzenberg v. K., M. Femández Núnez, H. Blaschke, N. Yevdakova, V. Motyka
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Analysis of cytokinin biosynthetic genes of the moss Physcomitrella. Poster, The 5th Plant Genomics European Meetings. The Annual International Conference. Venice, Italy. October 11 .-14. Oct. (2006)
Yevdakova N., K. v. Schwartzenberg
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(2007) Characterisation of a prokaryote-type tRNA-isopentenyltransferase gene from the moss Physcomitrella patens. Planta 226: 683-695
Yevdakova NA, Schwartzenberg v K
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(2007) Cytokininstoffwechsel bei Pflanzen - endogene und exogene Modulationen. Habilitationsschrift, Univ. Hamburg
K. von Schwartzenberg
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(2007) Molecular and biochemical evidences for tRNA-dependent cytokinin biosynthesis in the ancient land plant Physcomitrella patens (Hedw.) B.S.G, PhD-Thesis, Univ. Hamburg
N. Yevdakova
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2007. Cytokinins In the bryophyte Physcomitrella patens - analyses of activity, distribution and cytokinin oxidase/dehydrogenase overexpression reveal role of extracellular cytokinins. Plant Physiol 145: 786-800
Schwartzenberg v K, Fernandez Nunez M, Blaschke H, Dobrev PI, Novak O, Motyka V, Stmad M
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Distribution and activity of cytokinins in Physcomitrella. Poster, Botanikertagung Hamburg, 2. - 6 . Sept. (2007)
Fernández Núnez M., H. Blaschke, O. Novak, M. Stmad, V. Motyka, K. v. Schwartzenberg
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Distribution, activity and origin of cytokinins in Physcomitrella. Votrag Moss 2007, The Annual International Conference for Moss Experimental Research, Seoul, Süd-Korea, 5. Sept. (2007)
Schwartzenberg v. K., M. Femández Núnez, H. Blaschke, N. Yevdakova, M. Stmad
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Nukleinsäure, die für eine pflanzliche Adenosinnukleosidase kodiert. (DE 10 2007 008 890.8 und PCT/DE 2008/000305 (University Hamburg).
Schwartzenberg, Blaschke
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Cytokinins in Physcomitrella. Vortrag, Inst. f. Biologie / Angewandte Genetik, FU-Berlin, 9. Mai (2008)
Schwartzenberg v. K.
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Defining the functional significance of adenosine nucleosidase. Poster, CSPP-meeting, Ottawa, Canada, 14.-17. June (2008)
Engel K., Blaschke H., K. v. Schwartzenberg, B. Moffatt
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Identification of adenosine nucleosidase in Physcomitrella. Poster, Moss 2008, The Annual International Conference for Moss Experimental Research. Tampere, Finnland 15.-18. Aug. (2008).
Blaschke H., K. Engel, B. Moffatt, K. v. Schwartzenberg
