Spider silk is a versatile and high quality material, which is interesting for many different technical applications, for example in medicine, engineering and cell culture technology. A challenge on the way to the technical utilization of spider silk proteins is the cost-effective production in great quantities. Already at the lab scale, more than a gram of purified spider silk protein is necessary to enable a sufficient mechanical testing. In the frame of this work, different spider silk constructs were expressed in seeds of Nicothiana tabacum and the seed system was compared to the expression in leaves regarding the producible amount of transgenic protein. Furthermore, the longterm storage stability of spider silk proteins in seeds was checked at room temperature over a period of twelve months to establish the seed production as an uncomplicated production system for lab scale demands. The purification of the transgenic protein was done using the established inverse transition cycling method, which was expanded and optimized according to the new expression system in tobacco seeds. To achieve better material properties or to enable a future construction of fibers from spider silk proteins, it is desirable to further increase the size of the transgenic proteins. For this reason, dimerization tags were attached to different spider silk constructs and expressed in tobacco. This was followed by the posttranslational conjunction via bacterial transglutaminase.