Genetic and molecular analysis of metabolite-mediated signal transduction in Arabidopsis thaliana

• Applicant: Professor Dr. Wolf-Bernd Frommer
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 1994 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5153044

Intra- and intercellular communication is important for controlling and integrating metabolic processes in multicellular organisms, especially under conditions of varying environmental conditions. Therefore metabolite levels are constantly monitored using a variety of sensors. Sugar and amino acid sensing are poorly understood in higher plants. Using a genetic approach, a link was found between sugar and amino acid signalling. The respective mutant rsr1-1 is affected in both hexokinase-independent sugar signalling and is hypersensitive to proline. The project aims at two major goals: (i) cloning of the Rsr1 gene to establish its role in sugar and amino acid signalling and (ii) establishing the basis of the unusual phenomenon of proline sensitivity. Sensitivity to proline is counterintuitive and seems to be linked to production of reactive oxygen species (ROS), to PCD and to pathogen defence. In turn, mutants involved in pathogen defence show alterations in sugar sensing. Here the gene encoding P5CDH was cloned and a knock out mutant was isolated. A detailed characterisation of the mutant including array-based expression analysis will be used to obtain insight into regulatory functions of imino acid metabolism in mitochondria. The project may thus help to unravel the links between primary metabolism, programmed cell death (PCD) and pathogen defence and improve our understanding of PLS (physiological leaf spot disease).

• DFG Programme: Research Grants