How to tame a parasite - Developing biotechnological pipelines for gene function studies in Cuscuta

Cuscuta is a genus of parasitic plants that form cross-species bridges and connect to the xylem and phloem of a wide variety of host plants. Because of their unique lifestyle, research into processes like the formation of connections in between plant cells and plant immunity would benefit from Cuscuta as a model system. However, a method to study gene functions in a Cuscuta species is still missing. Its development was therefore chosen as the goal of this thesis. In vitro culture techniques for Cuscuta campestris were developed and Agrobacterium transformation of Cuscuta tissue was successfully performed in two different systems, the adhesive disk area close to the parasitic infection organ, and seedlings of C. campestris. As an alternative method for gene function studies in Cuscuta, virus induced gene silencing was tested in C. campestris. Mineral transport across the host-parasite border was studied and the potential use of interspecies plasmodesmata between Cuscuta and its hosts was investigated. The results presented in this thesis allow for first gene function studies in Cuscuta and are good foundations for the development of pipelines for transgenic plant production and gene silencing techniques. Challenges and opportunities with this system are outlined. The conclusions of this thesis will help to “tame” Cuscuta and use its unique physique and strategies for host plant infection to establish a model species for studying plant-cell connections, transport processes and plant immunity.