Topics
Our workgroup focuses on the following topics:
Elucidation of carotenoid biosynthesis (synthesis, catabolism, phytohormone production, regulation) and its translational application for the development of enhanced basic foods
Carotenoids are products of the plastidic isoprenoid metabolism. In plants they serve as photosynthetic pigments and antioxidants. They are also precursors of regulatory molecules, e. g. the phytohormones abscisic acid and strigolactone, and give also rise to numerous volatiles and ecologically active compounds. In general, these processes rely on catabolic reactions that are initiated by the cleavage of carotenoids.
The regulation and enzymatic function of this network is being explored with the help of model plants and non-model systems, as well as in vitro.
Some carotenoids are essential for human nutrition.Those like beta-carotene exhibit provitamin A activity and are converted to retinal, reduced to retinol or oxidized to retinoic acid by animal organisms. These so called retinoids possess a distinct physiological activity concerning health and the immune system.
Enhancement of carotenoid content and storage stability in Golden Rice and other crops
To fight vitamin A deficiency, key crops like rice (Golden Rice) are the subject of biotechnological research aiming at the improvement of provitamin A amounts. Priority is given to application here for increasing contents on the one hand and providing better storage stability of accumulated carotenoids on the other hand. Besides specialized transformation techniques, our workgroup employs particularly biochemical as well as analytical methods for this purpose. We cooperate with international organizations and research institutes for the combination of other nutritionally relevant properties.
Basic mechanisms in carotenoid biosynthesis
This field of research contains the transcriptional and post-transcriptional regulation of this multiply branched biosynthesis pathway. In addition, we explore the fundamental reactions through enzymology and structural elucidation (in cooperation with AG Einzle). At the moment, a special focus lies on membrane-associated reactions, which are being analyzed in biphasic liposomal approaches.
Improvement of metabolite flux through synthetic biology approaches
Synthetic biology brings the opportunity of investigating key elements of carotenoid biosynthesis in heterologuous systems to yield valuable insights into mechanisms and topology. Through combination and reorganization of enzymes it becomes possible to control and enhance metabolic flux for the synthesis of carotenoids. For this sort of stoichiometrically controlled 'pathway engineering' our workgroup relies on bacterial as well as (in cooperation with the Synthetic Biology Group) eukaryotic systems.
Yield enhancement
These works focus on rice with the aim to create an advantage for farmers who cultivate nutritionally improved (biofortified) varieties and thereby reduce the prices. Primarily, studies on programmed cell death (apoptosis) are carried out to reach this objective.
Development and optimization of analytical methods
Fundamental research as well as studies that strive to enhance nutrient contents require accurate qualitative and quantitative analytics. Therefore, high resolution mass spectrometry in liquid phase (LC-MS) and gas phase (GC-MS) as well as HPLC techniques are integral components in our lab that undergo constant development.
Our workgroup takes part in PSF|Plant Sciences Freiburg.