Plant Biotechnology

Plant biotechnology is a forward looking research area. The contribution of pure research, to the most part carried out in statutory research institutes, provides the essential basis for goal-oriented applications in modern agriculture. At the Albert-Ludwigs-University in Freiburg, innovative and competitive pure research in the field of plant biotechnology is taking place in many institutes from widely differing faculties (Biology; Forest and Environmental Sciences; Chemistry, Pharmacy, and Earth Sciences).
Exemplary is genome analysis, which forms the basis of the specific improvement of plant growth (e.g. stem rigidity of grass or salt tolerance, increased crop and vitamin enrichment of cereals). The data taken from research into plant architecture can be transferred to the field of mechanical engineering (e.g. composite material in the automobile industry, hollow chamber systems with "plant" mechanisms to withstand higher pressure loads).

PB-Director: Prof. Dr. R. Reski

Our projects:

	Seed quality and seedling performance PD Dr. G. Leubner
	Structural and mechanical properties of plants: transfer into technical materials Prof. Dr. T. Speck, Prof. Dr. H.-C. Spatz
	The photoregulation of plant architecture and performance Prof. Dr. E. Schäfer
	Signal transduction of plant tolerance to stress Prof. Dr. G. Neuhaus
	Functional genomics in plants using highly efficient homologous recombination Prof. Dr. R. Reski
	Physcomitrella patens as bioreactor for the production of heterologous pharmaceutically relevant proteins Prof. Dr. R. Reski, Dr. E. Decker
	Natural compounds from the rain forest - a potent source for drugs with anti-inflammatory activity Prof. Dr. I. Merfort
	Phytoremediation of heavy metals and pesticides by genetically engineered poplar trees Dr. A. Peuke, Prof. H. Rennenberg
	Nutritional Genomics: Generation of the first biofortified food (GoldenRice) and successful implementation of this technology to Third World countries Prof. Dr. P. Beyer
	Biomonitoring Pesticide Impacts on Aquatic Plants Prof. Dr. E. Wagner

PD Dr. G. Leubner

Seeds are the delivery systems for agricultural biotechnology. High quality seed leads to excellent seedling performance in the field. It is the ultimative basis of successful companies that breed crop plants for seed production. Seed quality is a complex trait that is determined by interactions between multiple genetic factors and environmental conditions. Modern approches to improve seed quality therefore combine classical genetics, plant molecular biology and a variety of seed technologies. These "seed biotechnologies" enhance physiological quality, vigor and synchronity to establish a crop in the field under diverse environmental conditions. Seed technologies include priming, pelleting, coating, "artificial seeds", and other novel seed treatment methods.

Our group has long research experience in basic and applied seed biology. The role of the seed covering layers for germination, water uptake, seed storage, after-ripening and dormancy release is an important research focus of our lab. We are interested in the molecular mechanisms of endosperm weakening and in the release of "coat-imposed" dormancy. The different covering layers are determinants of seed quality and exhibit the biodiversity of seed structures. Seed covering layers include endosperm, perisperm, testa (seed coat) and in many crop plants also pericarp (fruit coats).

We have expertise in various methods of seed and seedling technology, physiology, biochemistry and molecular biology. We collaborate with international companies that produce, store and sell seeds for field crops and ornamental plants. Our basic and applied seed research projects focus on environmental factors (light, temperature, water) and on plant hormones as endogenous regulators (gibberellins, abscisic acid, ethylene, auxin, cytokinins, brassinosteroids). The utilization of plant hormones and inhibitors of their biosynthesis and action in seed treatment technologies affects seed germination and seedling emergence. The genes, enzymes, signaling components and down-stream targets of plant hormones provide molecular marker for seed quality and seedling performance.

Direct contact and further information:

PD Dr. G. Leubner Institut für Biologie II/Pflanzenphysiologie Schänzlestr. 1, 79104 Freiburg Tel. +49-761-203-2936, Fax. +49-761-203-2612 EMail

Homepage "The Seed Biology Place"

Prof. Dr. T. Speck, Prof. Dr. H.-C. Spatz

Biological materials and structures have incredibly favorable mechanical properties in relation to their weight, plant fibers for example displaying great stiffness and strength.The usage of biological materials and the simulation of natural structures and principles of construction are of great importance for future technical development. Together with the research department of Daimler-Chrysler AG, this project was initiated to develop shock absorbing materials based on natural plant structures One of the major properties of biological structures is their ability to absorb mechanical energy through plastic deformation and visco-elastic reaction. When plant fibers are embedded in plastic in a complex structure based on natural models, a high level of shock absorption can be achieved. In addition to these favorable mechanical properties, other advantages of compound material reinforced by plant fibers include:

1. the lightness of plant fibers (when dry) as compared to the often used glass fibers
2. the good biodegradability of plant fibers, as a result of which the plastic matrix is also broken down into small, easily biodegradable particles (due to its large surface area),
3. the residue-free burning of compound materials with a large proportion of natural fibers
4. the fact that plant fibers are a self-replenishing natural resource, flax for example making so few climatic or nutritional demands that it grows even in areas otherwise unsuitable for cultivation.

Direct contact and further information:
Prof. Dr. T. Speck
Botanischer Garten
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2875, Fax. +49-761-203-2880
EMail     Homepage

Prof. Dr. E. Schäfer

In the framework of PHOTOARCH-BIO 4-CT-972124 several research groups from UK, NL, F, G and I analyse the potentials to modify plant architecture and performance by introducing photoreceptor genes and genes encoding signal transduction elements into crop plants. Plants sense their neighbours by the spectral differences in the reflected light and response in modifying the translocation of resources to stem and internode growth instead of leaf and storage organs. It was demonstrated that by overexpression of photoreceptors this reaction could be strongly modified.

In our group we analyse modified photoreceptors after expression in yeast cells, test intracellular localisation of the photoreceptor and its function on photomorphogenesis in transgenic plants and screen for novel signal transduction mutants.

The aim is to alter the physiological activities of the photoreceptors to fine tune their functions after overexpression in crop plants. This should allow specific modification of plant architecture depending on the environmental light conditions and density of planting.

Direct contact and further information:
Prof. Dr. E. Schäfer
Institut für Biologie II
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2683, Fax. +49-761-203-2629
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Prof. Dr. G. Neuhaus

Changes in cell behaviour induced by external stimuli require execution of complex programmes of events controlled by stimulus-response coupling: a stimulus is perceived by the cell, a signal is generated, transmitted (signal transduction), and a response (e.g. gene activation) is instigated. This process normally requires the recognition of the stimulus by a receptor, and a subsequent use of chemical second messengers and/or effector genes (e.g. protein kinases) that will then trigger an appropriate response. Because of their high degree of interconnection, such systems of interacting proteins and second messengers act as neural networks trained by evolution to respond appropriately to patterns of extracellular stimuli.

Freezing stress is one of the most important factors that limit plant growth, productivity, and distribution (Sarhan et al 1997). Freezing damage is often accentuated under high light conditions suggesting the involvement of activated oxygen species (AOS) . Plant species, such as Arabidopsis, that normally experience freezing temperatures during vegetative growth, have the ability to increase their freezing tolerance by a process called cold acclimation (for review see Thomashow 1999). Cold acclimation in herbaceous plants is triggered when plants are exposed for several days to low, non-freezing temperatures. In addition, other factors such as mild water stress, and application of the plant growth hormone abscisic acid (ABA) can induce an increase in freezing tolerance (Chen et al 1983, Lang et al 1994). These observations already indicate that the biological phenomenon of cold acclimation interacts and crosstalks with several signal transductions pathways in plants. This raises several important questions: Which genes have an important role in this process? What is their function and how they are regulated? How do plant sense low temperature? Which signal cascades are activated by cold? How is this network of signal pathways regulated? In recent years a lot of important information have been gathered on molecular mechanisms in cold acclimation and freezing tolerance (Thomashow 1999, Hughes and Dunn 1996). However our overall understanding of this biological phenomenon remains far from complete. Specially in dissecting the different signal cascades only little information is available. Calcium and several genes encoding signalling proteins (MAP-kinases. CDPK, and calmodulin regulated kinases) have been found to be upregulated in response to low temperatures ( Tahtiharju et al 1997, Monroy et al 1998, Jonak et al 1996, Knight et al 1996, Polisensky and Braam 1996). However, no direct evidence has been obtained on their signalling role in cold acclimation and freezing tolerance. In addition, a putative negative regulator loci (HOS1; Ishitani et al 1998, Ishitani et al 1997, ) has been identified by a genetic approach and is assumed to play a triggering role in signalling, low temperature, and ABA. However, a clear understanding of the whole signal network and its crosstalk/s with other cascades (e.g. ABA, light, water stress) is still missing.

The approach taken from our group and one partner lab will be focussed on the dissection of the signalling events induced by cold acclimation and the subsequent crosstalks;one lab (Salinas, Madrid) which have long experience in the molecular analysis of cold stress and cold acclimation response; one lab (Neuhaus), which expertise lays in the analysis of signal transduction pathways by microinjection and cell imaging (luciferase and aequorin) will join to use their whole expertise to get a first insight in the hierarchy of the signalling network induced by low temperatures.

Direct contact and further information:
Prof. Dr. G. Neuhaus
Institut für Biologie II
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2673, Fax. +49-761-203-2596
EMail     Homepage

Prof. Dr. R. Reski

Early 1999 a major industrial co-operation started within the Freiburg Center of Applied Life Sciences (ZAB): The BASF AG Ludwigshafen committed itself to invest DEM 30 Mio. for the next four years into a functional genomics project on the moss Physcomitrella headed by Prof. Ralf Reski, Department of Plant Biotechnology at the Albert-Ludwigs-University Freiburg. The university itself will invest about DEM 4 Mio. into this project. Within less than half a year a university building was reconstructed and equipped for the needs of this project.

To day, Physcomitrella is the only land plant with an efficient system for homologous recombination in its nuclear DNA, being an ideal system for studies of gene function via targeted gene knockout. Reski and his group of about 45 members will generate a collection of about 100,000 transgenic plants based on this homologous recombination, to generate a saturated mutant collection, which in forthcoming projects can be screened for "loss of function mutations". Likewise, about 100,000 expressed sequence tags (ESTs) will be produced from Physcomitrella, in order to identify genes novel to plants. The function of some of these genes will be identified by targeted knockout. In this four-years-project, Reski hopes to identify about 100 moss genes relevant to biotic and abiotic stresses and to certain metabolic pathways. These genes will be integrated by the BASF AG into crop plants to improve several input- and output-traits.

Physcomitrella patens as bioreactor for the production of heterologous pharmaceutically relevant proteins

Prof. Dr. R. Reski, Dr. E. Decker

Direct contact and further information:
Prof. Dr. R. Reski
Institut für Biologie II, Pflanzenbiotechnologie
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-6969, Fax. +49-761-203-6967
EMail     Homepage

Dr. E. Decker
Institut für Biologie II, Pflanzenbiotechnologie
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2820, Fax. +49-761-203-2612
EMail     Homepage

Prof. Dr. I. Merfort

Costa Rica belongs to those countries in the world which are very rich in species. Plants from the tropical rain forest produce secondary metabolites with a variety of biological effects. They can be considered as potential drugs, e.g. as part of extracts, pure compounds or lead compounds for the development of synthetic drugs.

In our project plants from the tropical rain forest are studied for anti-inflammatory active compounds using modern phytochemical and biological-pharmacological methods. Transcription factors, such as NF-κB and NF-AT, serve as molecular targets. They play a pivotal role in inflammatory processes and in the immune system, by regulating the transcription of a variety of proinflammatory cytokines, chemokines, adhesion molecules and inflammatory enzymes like iNOS, COX-2, 5-LOX and cytosolic phospholipase A₂. Influencing their activities offers interesting possibilities in the therapy of acute and chronic diseases such as rheumatoid arthritis. Drugs acting in such a way differ from the common non-steroidal antiphlogistic drugs which influence enzymes of the arachidonic acid metabolism.

Sesquiterpene lactones are an example of compounds possessing considerable anti-inflammatory activity. They inhibit the transcription factor NF-κB by selectively alkylating its p65 subunit. Moreover, they can serve as lead compounds for the development of potent anti-inflammatory drugs.

Goals of the project:

• Research for effective compounds in preparations of medicinal plants used in traditional medicine
• Elucidation of the molecular mechanism of action
• Research for anti-inflammatory active drugs with transcription factors (NF-κB and NF-AT) as molecular targets
• Research for lead compounds by carrying out QSAR studies and calculating neuronal networks

References:
GARCIA-PINERES, A., CASTRO, V., MORA, G., SCHMIDT, T.J., STRUNCK, E., PAHL, H.L., MERFORT, I.: Cysteine 38 in p65/NF- B plays a crucial role in DNA binding inhibition by sesquiterpene lactones; Journal of Biological Chemistry 276, 39113-39720 (2001)
MÜLLER, S., MURILLO, R., CASTRO, V., BRECHT, V., MERFORT, I.: Sesquiterpene lactones from Montanoa hibiscifolia inhibit the transcription factor NF-kB. J. Nat. Prod. 67: 622-630 (2004)
SIEDLE, B., GARCIA-PINERES, A.J., MURILLO, R., SCHULTE-MÖNTING, J., CASTRO, V., RÜNGELER, P., KLAAS, C.A., Da COSTA, F., KISIEL, W., MERFORT, I.: Quantitative structure-activity relationship of sesquiterpene lactones as inhibitors of the transcription factor NF- B, J. Med. Chem. 47: 6042-6054 (2004)

Direct contact and further information:
Prof. Dr. I. Merfort
Institut für Pharmazeutische Wissenschaften
Lehrstuhl für Biologie
Stefan-Meier-Str. 19
79104 Freiburg
Tel. +49-761-203-8373, Fax. +49-761-203-8383
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Dr. A. Peuke, Prof. Dr. H. Rennenberg

Tree biotechnology is becoming an increasingly important tool for the remediation of contaminated environments, because trees have extensive root systems to ensure an efficient uptake of pollutants from the soil and provide the possibility of several cycles of decontamination with the same plants. Genetically modified poplar trees with increased resistance to heavy metals and pesticides might thus represent the superior plant species for this purpose.
Glutathione (GSH) and its derivatives play the major role in plant defense against these pollutants. Pesticides are detoxified by conjugation with GSH by glutathione S-transferase and subsequent excretion of these conjugates in the vacuoles. Heavy metals induce synthesis of a wide range of cysteine-rich peptides and proteins, including metallothioneins and phytochelatins (PC). The latter are synthesised enzymatically from glutathione, bind the metals with high affinity and the PC-metal complex is sequestered to the vacuole.
In a current field trial transgenic poplars (Populus tremula x P. alba) with enhanced GSH synthesis (overexpressing the gene for -glutamylcysteine synthetase (gshI) from E. coli in the cytosol) and hence elevated capacity for phytochelatin production are compared with wildtype plants for the removal of heavy metals at different levels of contamination and under different climatic conditions. In greenhouse experiments under controlled conditions these transgenic poplars showed a high potential for uptake and detoxification of heavy metals and pesticides. This capacity is evaluated in field experiments. Further aims of the project are to elucidate (a) the stability of the transgene under field conditions and (b) the possibility of horizontal gene transfer to micro-organisms in the rhizosphere. For the execution of the project experimental plots in Germany (Saxonia Anhalt, district Mansfelder Land) and Russia (Middle Urals, Swerdlovsk oblast) in copper mining areas were built up, to compare moderate middle European with extreme continental climate.The results will help to assess the capacity and the biosafety risk of the use of transgenic poplar for phytoremediation of soils.

Direct contact and further information:
Prof. Dr. H. Rennenberg
Institut für Forstbotanik und Baumphysiologie
Am Flughafen 17
79085 Freiburg
Tel. +49-761-203-8301, Fax. +49-761-203-8302
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Prof. Dr. P. Beyer

At the Center for Applied Biosciences (ZAB), Prof. Dr. Peter Beyer, Professor for cell biology, is one of the two inventors of GoldenRice. He uses a 'Nutritional Genomics' approach to develop biofortified rice. Stably producing high amounts of provitamin A GoldenRice is to fight vitamin A deficiency causing more than 500,000 children to go blind each year and a leading cause of child mortality in developing countries.

At the time his group is the European partner in the newly formed CGIAR Challenge Program 'HarvestPlus', an interdisciplinary, global alliance of research and implementing institutions. With a funding of roughly $50 million for the next 4 years HarvestPlus aims to develop micronutrient-rich (e.g. iron, zinc, provitamin A) crop varieties of cassava, sweet potato, wheat, maize, beans, and rice, demonstrate their impact on human nutrition, and transfer the technology and products to the people at most risk of being micronutrient deficient.

Homepage of the CGIAR Challenge Program HarvestPlus

Read the Biofortification Brochure (731 KB, local copy)

Direct contact and further information:
Prof. Dr. P. Beyer
Institut für Biologie II
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2529, Fax. +49-761-203-2675
EMail

Prof. Dr. E. Wagner

The investigation of pesticide impact on aquatic plants aims

• to understand the reaction of plants due to toxic effects,
• to support risk assessment as well as
• to influence test species and test method selection.

Direct contact and further information:
Prof. Dr. E. Wagner
Institut für Biologie II
Schänzlestr. 1
79104 Freiburg
Tel. +49-761-203-2637, Fax. +49-761-203-2840
EMail     Homepage