Reactive oxygen species (ROS) are important modulators of plant development and they accumulate in tissues upon various kinds of abiotic stresses imposed by e.g. elevated temperature or drought. ROS are also intimately linked to programmed cell death (PCD). Cellular ROS activity is controlled by a large cohort of ROS forming and scavenging enzymes, signalling proteins and transcription factors that together constitute an intricate ROS functionality network that balances growth against the negative impact of environmental stress. A detailed understanding of plant ROS biology is thus of great agronomic importance. Previously, a novel mutant, called atr7, was isolated from Arabidopsis thaliana and shown to display a remarkable tolerance to oxidative stress-inducing agents such as paraquat or the catalase inhibitor aminotriazole. The ATR7 gene has been isolated recently, however knowledge about the function of its encoded protein, its mode of action, cellular localization, and its potential interaction partners remains very limited so far. In addition, virtually nothing is known about the cellular and stress-specific expression patterns of ATR7 or its integration into signalling networks. The project therefore aims at unravelling the biological role of ATR7. To this end, transgenic plants with altered ATR7 expression levels (knockout, amiRNA and overexpressor lines) will be grown under normal and oxidative stress-eliciting conditions and subjected to comprehensive analyses (including transcriptomics and metabolomics, and others) to identify genes, metabolites, and biochemical pathways likely to be responsible for the acquisition of stress tolerance. An important part of the project will be training of the researcher in modern genomics and metabolomics methods on state-of-the-art instruments available at the host institution. The researcher will then utilize the know-how and practical experience at the newly established Genomics Research Center at his home institution.