We will generate a knowledge base for the rational eco-engineering of sites polluted with recalcitrant herbicides atrazine, 2,4-D and analogues. To understand the roles of complex microbial communities for degradation processes, and adaptabilities of communities to stress conditions we will develop, based on detailed metabolic information, molecular biology tools, to study community functions, interactions and adaptations. DNA arrays for phylogenetic, catabolic and stress studies will be designed and optimised. Information recruited in model systems will be used in systems of increasing complexity, aiming at the rational manipulation and optimisation of degradative activities, including the contribution of rhizosphere microbial communities