Biotic and abiotic stresses are major components of natural selection in the wild. In nature, plants have to cope with a wide range of biotic and abiotic stress conditions. Recent genomics research revealed that the plant’s capacity to respond to this enormous diversity of stresses is highly flexible and finely balanced. As plants have co-evolved with an enormous variety of microbial pathogens and insect herbivores under conditions with different types of abiotic stress (heat, cold, water logging, drought, toxic compounds, etc.), they harbour a fantastic reservoir of natural adaptive mechanisms to simultaneously cope with different forms of biotic and abiotic stress that until to date remained unknown or poorly understood .Using a multidisciplinary approach, I will explore the resource of natural adaptive stress responses in Arabidopsis thaliana to simultaneous interaction with biotic (necrotrophic pathogen Botrytis cinerea) and abiotic (drought) stress. With the proposed research I aim to understand how and why plants integrate different signals to effectively defend themselves against different threats.State-of-art bioinformatic tools based on whole genome expression profiling will be used to build a gene regulatory network model of the a(biotic) signal interaction. This dual approach will allow me to uncover novel regulators of pathway crosstalk by which plants steer their immune signalling network upon encounter with multiple stress and to investigate their biological significance. The future objective is to convert all this knowledge to provide novel tools for sustainable agriculture and resistance breeding, and apply these tools to crop plants.