This paper illustrates a year-long case study investigating in-service teachers' needs and mentor's practices in implementing cutting-edge research science topics as nanotechnology and plastics in the ocean in primary education. In a Community of Learners design and with the support of a mentor, ten primary teachers implemented in 6th grade students a teaching-learning sequence either on "Nanotechnology Applications" or on "Plastics--bane of the ocean." Data were mainly collected by audio-recordings of the training meetings. The results give insights in primary teachers' needs when implementing such topics and mentor's practices in order to support them in this endeavor. Specifically, they indicate increased teacher needs on instructional strategies of approaching cutting-edge research topics. These needs were covered by the mentor employing a wide range of practices, mostly by directly guiding and modeling the conduction of activities.