From vectors to applications to cellular functions. Introduction of genetic information into target plant cells and acquisition of new data as a result of transgene expression may require a network of modular vectors, flexible gene cloning and expression systems, and specialized plasmids that result in different modes of transgene expression. Modular vectors may represent a starting point for assembly of custom-made expression vectors, multigene expression vectors, and other types of plant transformation vectors. These vectors in turn provide the users with the abilities to overexpress and down-regulate genes, as well as with the capacity for specific, and often unique, applications, useful for obtaining novel traits and functional data, protein imaging in living plant cells, and generating transgenic plants for plant research and biotechnology.