METABOLIC ENGINEERING STRATEGIES FOR THE OPTIMIZATION OF MEDICINAL AND AROMATIC PLANTS: EXPECTATIONS AND REALITIES

Abstract

In recent years classic genetic and molecular biology strategies (Bioballistics, Agrobacterium tumefaciens transformation, recombinant enzymes) for production of natural compounds or even breeding of medicinal and aromatic plants have expanded and improved productivity of plant-derived fine chemicals. Among those high value natural products with medicinal and cosmetic purpose (e. g., essential oils, paclitaxel, artemisinine, Vinca-Alkaloids) play a major role. Applying genetic and biotechnological techniques like metabolic engineering, site directed mutagenesis, and pathway optimization for plant optimization to reduce costs and increase productivity are in the main focus of academia and industry. Because of some drawbacks with plant cell cultures and isolated enzymes giving no sufficient high production for commercialization, research strategies shifted more and more to metabolic engineering. From the past, engineering a microorganism is proven as a valuable tool and concepts have been transferred to plant science and opened new promising perspectives for improving plants and cell lines. First, engineering crop plants was conducted, but applying these techniques for medicinal plants is rather new and has not yet been explored so well. Today cloning and expression of multiple genes in polycistronic vectors and genomic integration is of high interest and allows the reconstitution of biosynthetic pathways in heterologous organisms either plants or microorganisms. Combining science and engineering in this research field was claimed as Combinatorial Biosynthesis and later as Biology. Synthetic biology includes a large number of subareas, including enzymology, protein assembly and interactions, metabolomics, gene regulation, signal transduction and computational biology and is considered as a future approach for biotechnological plant optimization. The possibilities show exciting perspectives for the exploitation of medicinal and aromatic plants to increase the level of wanted natural products, gain insight in metabolic pathways even for new biosimilar chemicals, to improve nutrional and health promoting effects of food (nutraceuticals), and to reduce the amount of unwanted by-products with potential toxic or allergic activities.