Conference Crossing Kingdoms, the final conference of the project SMARTPLANTS took place at  Sainsbury Laboratory at University of Cambridge 16.-18. April, 2018. Crossing Kingdoms is an international 3 day-event bringing together scientists from the microbial, animal and plant fields (Kingdoms) to present their results and highlighting how knowledge from these different life forms provide tools for synthetic biology innovations and applications. The SMARTPLANTS project members had several presentations of project results.