The dynamic networks of plant natural products – the basis for flexible adaptation and biodiversity
As a consequence of their sessile lifestyles, plants have evolutionary developed into specialists of flexible adaptation with high levels of resistance. Thus, the resulting biodiversity is reflected in an enormous chemical diversity of plant natural products. The typal patterns of these natural compounds get an extra dimension of complexity by dynamic changes during plant development and adaptation to fluctuating environmental and site conditions. Besides a plasticity of directional growth, plants respond to environmental changes and local challenges with a flexible reorientation of their central and peripheral metabolism. By means of low molecular substances, external resources are being developed up to maximum, pathogens and herbivores are being defended or the chemical communication with other organisms is being supported efficiently. Plant adaptation responses to changing external conditions are regulated by the involvement of multiple and highly complex information processing molecular networks and realized at a cellular and systemic level. Thus, the knowledge of structure, synthesis, function and modes of action of biologically active metabolites and intermediates is a prerequisite for a comprehensive understanding of plant diversity as well as growth and development supporting adaptation processes. This gain in knowledge leads to new ways in a sustainable plant production and to an innovative biotechnology as well as the development of active compounds as a basis for a plant-based bio-economy.
Interdisciplinary theme-based research at the IPB
The research mission of the Leibniz Institute of Plant Biochemistry (IPB), which gains increasing social relevance in the course of global changes, is implemented by a unique constellation and concentration of chemical and biological competencies in four scientific departments and two junior research groups. This scientific expertise allows a close thematic and cooperative connection of bioorganic chemistry, biochemistry and plant biology, which is supported by mutually established and used technological platforms and databases.
Analysis of fungal and plant natural products – the basis for the development of new active compounds and pathfinder for a plant-based bio-economy
The comprehensive analysis of plant and fungal natural products is a central focus in the research concept of the institute, which is associated to further research priorities. For a comprehensive qualitative and quantitative detection of natural compounds in biological materials as well as the investigation of their structure, modern analytical methods are used and newly developed in an interdepartmental sphere of competence. This forms the basis for the investigation of biological functions of natural products and their biosynthesis and also for the discovery of new lead structures. The structure elucidation, chemical synthesis and derivatization of natural products make an important contribution to the investigation of their biological activity, extension of their structural diversity and development of active compounds. The characterization of enzymes and regulatory proteins as well as their coding genes allows the study of the cellular, tissue-specific and systemic organization of biosynthetic pathways, their control levels as well as plant production and storage processes. This knowledge is the basis for the development of biocatalysts, which allow environmentally friendly, sustainable processes but also the access to complete new products. In the face of decreasing resources, both in the petrol field and from natural sources, biotechnological and especially plant-based production processes are the key to knowledge-based bio-economy.
Investigation of molecular interactions – mechanisms and networks of chemical communication
The genetically determined plant development and its modulation in the context of adaptation to environmental and site conditions are based on receptor-mediated perception of abiotic and biotic parameters and on the generation of stimulus-specific endogenous signals. The information content of chemical signal carriers is interpreted by cellular and systemic networks and is then converted directly into physiological adaptation responds by means of changed gene expression patterns. The adaptation reactions are generally related to transient and local changed profiles of specific metabolites. The basis for these processes is formed by manifold molecular interactions. Thus, their interdisciplinary analysis is of central importance for the research concept of the institute.
The interactions of proteins with low molecular ligands or between macromolecules as well as covalent modifications of proteins and nucleic acids form functional modules for these molecular processes and are also suitable priority objectives for the applied active compound research. Based on these aspects, the mechanisms of chemical communication, especially between plants and fungal symbionts or phytopathogens as well as the organization of signal transduction, biosynthesis, transport and degradation pathways are examined. Therefore, comprehensive analyses of the transcriptome, proteome and metabolome are used, which quantify and catalogue increasingly the tissue and cell-specific profile changes.
Furthermore, the application and development of modern cell biological methods, within the scope of interdepartmental technological platforms and collaborations, allow the analysis of dynamic molecular interactions in vivo. The chemical structure of interacting molecules is being modified by genetic engineering, directed evolution and chemical derivatization. Thus, the effects of changes can be investigated on suitable models or by screening methods that lead finally to the selection of molecules with the desired properties (e.g. active compounds, signal carriers, enzymes). The basis for this is formed by the development of new synthesis and selection processes as well as suitable assay and analysis methods that are supported by the visualization of molecular interactions by modeling.
Identification and functional characterization of unknown genes
The close combination of bioorganic chemical, biochemical, molecular biological, genetic and cell biological research approaches allows a function-based gene identification as well as new experimental accesses to gene function analysis that forms the third research priority at the institute. Genetic approaches on model and crop plants, like mutagenesis, analysis of the natural variability or methods of chemical genetics, accelerate the identification of unknown genes and informative alleles with essential and quantitatively graded functions in plant metabolism. In the overall concept, analyses of trancriptome, proteome and metabolome are following in order to functionally characterize genes that play an important role for the plant development and adaptation in the context of metabolism of natural products. Due to the increasing number of sequenced plant genomes and trancriptomes, systems biology approaches for the analysis of metabolic and regulatory networks gain in importance.
Bio- and chemoinformatical data processing links the research priorities at the IPB
The storage, analysis and linking of the enormous data amounts that are generated in the three research priorities – natural products, molecular interactions, gene function analysis – is only possible by using integrated bio and chemoinformatics. Especially the metabolome and proteome analyses require new methods of metabolite identification, data analysis and processing as well as the linking between the comprehensive data records of sequence, expression and active compound analyses. Informatics enables the decryption of connections, the prediction of characteristics of structural completely different data records and thus leads to a better understanding of the biological plant system.
At the reductionist level of knowing, detailed biochemical investigations of gene products, structural and functional analyses as well as molecular interaction studies are the prerequisite for a comprehensive molecular understanding of gene, protein and metabolite functions and thus for a targeted active compound research. The use of specific alleles, relevant mutants and transgenic plants allows not only the biological analysis of gene function but also the generation of model plants with changed profiles of natural products, new ingredients for health prevention or improved adaptation to specific sites and environmental situations. Such experimental plants are indespensable as biological test systems for the breeding of resource-conserving crops and for the sustainable production of valuable natural products and biocatalysts with a high degree of application relevance.