Title: DiKo: Annika Guse
Start date: Oct 17 2017
Start time: 03:00 pm
End time: 04:00 pm
Organizer: Patrick Mueller
Location: Max Planck House Lecture Hall

Many animals establish symbioses with microorganisms to gain an ecological advantage. A remarkable example is the endosymbiosis between corals and dinoflagellates (genus Symbiodinium), which provide photosynthetically fixed nutrients to enable coral survival in nutrient‐poor tropical oceans. Many reef-building corals acquires symbionts during planula larval stages from the environment anew each generation. To date the molecular mechanisms underlying symbiosis establishment are poorly understood mostly because corals are not suitable as model systems. Here I will present our advances in developing larvae of Aiptasia, a marine sea anemone, as a tractable model to dissect fundamental aspects of symbiosis establishment at the mechanistic level. I will summarize our currently available resources and experimental toolkit for Aiptasia, and present two ongoing projects in more detail. The first project aims to uncover how symbionts avoid phagolysosomal digestion by the host - the default pathway when a foreign cell enters an animal cell. The second project addresses how key nutrients are transferred between the two partners. The latter uses the role of Niemann-Pick type C (NPC2) proteins and their role in sterol transfer from symbiont to host as a paradigm for the metabolic exchange that is a prerequisite for the biodiversity and productivity of the whole coral reef ecosystem.