Ruprecht-Karls-Universität Heidelberg
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Plant Molecular Biology

Dr. Michael Buettner

Dr. Michael Buettner
Im Neuenheimer Feld 360
69120 Heidelberg
Fon 06221 54-5536
Fax 06221-54 5859
michael.buettner AET



Research profile

Sub-cellular sugar partitioning

In higher plants, sugars play important roles as nutrients as well as signal molecules during the entire life cycle. While the green parts (source) synthesize sugars during the day, non-green parts (sink) depend on a constant import of carbohydrates delivered via the phloem. In addition, source and sink cells allocate sugars between different cellular compartments, depending on the actual requirements. During the day, many plant species use up to half of their assimilated carbon for starch synthesis and transient storage in chloroplasts of source leaves. At night, transitory starch is degraded to glucose or maltose, which can then be exported from the chloroplast. Furthermore, hexoses can be imported into the vacuole for transient or long-term storage. The distribution of sugars on the sub-cellular level but also for long-distance transport requires several essential transport steps across membranes. Experiments on isolated vacuoles provided biochemical evidence for the uptake of hexoses into these organelles, and both mechanisms, passive diffusion as well as active transport have been suggested. However, very little is known about the corresponding transport proteins. My group has started to identify and characterize transporter proteins which mediate sub-cellular sugar partitioning in order to develop a clearer picture of how plants exploit different types of monosaccharide transporters during development and stress responses. Our molecular tools comprise biochemical as well as molecular and cell biological methods to elucidate the functional role of these sugar transporters in plants. We further use baker's yeast as heterologous system to study the properties of sugar transporters.

 Cellular Sugar Distribution

Curriculum Vitae

1993 PhD, University of Regensburg, Germany
1993-1994 Postdoc with G. Hauska, University of Regensburg
1994-1997 Postdoc with K. Singh, UCLA, Los Angeles, USA
1997-2004 Postdoc with N. Sauer, MPP, University of Erlangen
2004 Habilitation in Molecular Plant Physiology, University of Erlangen
2004-2008 Group leader, MPP, University of Erlangen
since 2008 Group leader, HIP, University of Heidelberg

/var/www/cos/ / Dr. Michael Buettner _e