Due to the emerging resistance of bacterial pathogens against commonly used drugs, there is an urgent requirement for new antibiotic compounds and lead structures. The European Commission encouraged researchers to investigate this problem in a holistic manner. Recently bacteria with complex lifestyles and intensive “crosstalk” came into focus as potential source for new small molecule lead structures which might be further developed as therapeutic agents. Planctomycetes comprise ideal candidates, since these ubiquitous occurring organisms, which reproduce via budding, form cell aggregates, such as biofilms and “marine-snow”. Beside their complex lifestyle, they comprise sub cellular compartments resembling the eukaryotic nucleus which questions the pro-/eukaryotic dichometrie. Thus, they combine a complex lifestyle with interspecies communication, which is required for biofilm formation. However, in-depth analysis of Planctomycetes secondary metabolite production has been hampered by the lack of a genetic system. Consequently the major objective of this proposal is the construction of a genetic system for Planctomycetes. Such a system would allow e.g. the construction of deletion mutants and the identification of secondary metabolites while comparing these mutants against the wild type strain. In addition the genetic system will be highly beneficial for applications beyond the proposed project, since e.g. genetic modification of Planctomycetes which play an important role in waste water treatment will result in further biotechnological applications. In addition to the development of the genetic system, the capability of small molecule synthesis will be investigate via genome mining of the already sequenced Planctomycetes species. Further more surrogate genetic experiments will allow the cloning and heterologous expression of secondary-metabolite related genes and operons, which subsequently enables small molecule structure determination and characterization.