D-A-CH Project: Regulation of primary metabolism under oxidative stress

• Applicant: Professor Dr. Arnd Göran Heyer
• Subject Area: Plant Physiology
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 262621824

Due to their sessile lifestyle plants are significantly affected in their distribution and performance by many abiotic factors. Water supply, temperature and soil quality are most relevant and share similar effects on plant growth. At the cellular level, these stressors can cause damage to membranes and proteins, and in many cases this is entailed by oxidative stress, resulting from intracellular production of reactive oxygen species. Previous studies revealed significant differences in stress tolerance of the model plant Arabidopsis thaliana to be correlated with accumulation of soluble carbohydrates and increased enzyme activities of the central carbohydrate metabolism. Yet, studies also indicated the necessity of analysing subcellular organisation of the whole primary metabolism to allow drawing a representative picture of the complex mechanisms involved in plant stress response.In the proposed project, we aim to dissect metabolic and signalling effects on primary metabolism caused by oxidative stress at the subcellular level. Our project is set out to elucidate diurnal regulation and compartment interactions contributing to the re-adjustement of redox homeostasis after a disturbance by abiotic stresses. Plants of the Arabidopsis thaliana accession Columbia-0 as well as the gin-2 mutant defective in hexokinase 1 and the S177A complement of its hexose sensing function will be exposed to conditions of light, heat and cold stress. For subcellular analysis of primary metabolism, the non-aqueous fractionation (NAF) technique will be applied in combination with high-throughput measurement of the metabolome and proteome. The proposed novel combination of NAF with shotgun proteomics, metabolite profiling and refined data processing techniques are intended to present a more precise picture of the plant cell as a system co-ordinating redox and metabolic activities of its subsystems. This shall involve the compartment-specific analysis of low molecular weight ROS scavengers like ascorbate as well as indicators of oxidative damage, e.g. malone dialdehyde and protective molecules like sugars or proline. Mathematical modelling of both diurnal dynamics and subcellular metabolic interactions of leaf primary metabolism shall yield information about bottlenecks for metabolic adaptation to abiotic stress. Beyond biochemical analysis and comprehensive systems biological characterization of plant-environment interactions, this project intends to contribute an enhanced methodology that allows understanding of the interplay of the different reaction spaces within a plant cell. We intend to simulate whole cell redox adjustments, thus proving or disproving the concept of a cellular redox state. This should, in turn, burst breeding concepts aimed at improving plant abiotic stress tolerance.

• DFG Programme: Research Grants
• International Connection: Austria
• Participating Person: Professor Dr. Wolfram Weckwerth