Plant secondary metabolism in the post-genomic era

The biotechnological production of high-value plant secondary metabolites in cultivated cells is an attractive alternative to isolation processes from the intact plants or to the total chemical synthesis. However, plant metabolic engineering has met only limited success, in sharp contrast to microorganisms, since our knowledge on biosynthesis of secondary metabolites is still very limited. Despite of the rapid development of not only plant genomics but also of analytical tools genetic maps of biosynthetic pathways are far from complete. Furthermore, regulation of the individual steps leading to the desired end-product is poorly understood. We have developed a SoluCel® technology platform based on genome-wide identification and functional analysis of genes involved in the production of plant-derived small molecules. It allows the exploitation of these genes in order to produce already existing secondary metabolites at higher levels in cell and tissue cultures through metabolic engineering. Moreover our combinatorial biochemistry approach allows to increase the chemical diversity of plant-based molecules thus offering novel molecules for the industry. A proof-of-concept has first been gained using tobacco cells as a model system. The technology was further applied to several medicinal plants. Using cDNA-AFLP based transcript profiling linked to our UPLC-MS or GC-MS metabololite profiling platform, an inventory of hundreds of genes, potentially involved in secondary metabolism, has been built. The functional analysis of these genes alone or in combination has shown clearly enhanced or altered metabolite accumulation patterns both in tobacco and in other plants. With this technology we are able to offer new opportunities to exploit the entire metabolic repertoire of a plant cell, and to create higher quatities of known metabolites or novel compounds that may find applications not only in pharmaceutical but also in chemical or biotechnological industries.