First holistic functional exploration of a marine photosymbiosis using the new model organism Symsagittifera roscoffensis – Animalga

The main drawback of the coral-algae model is that the microalgae Symbiodinium are refractory to molecular biology techniques, which seriously restrict any functional exploration. In this proposal, this obstacle is circumvented by the use of a new emerging model, the photosymbiotic worm Symsagittifera roscoffensis. This flatworm establishes a sustainable photosymbiosis with a green alga Tetraselmis convolutae. This symbiotic association has many major assets (i) a complete life cycle of worms amenable in laboratory conditions (ii) a functional approach on the green algae The aim of the ANIMALGA project is therefore to combine a functional approach on the photosymbiont T. convolutae and the use of free-algae juvenile worms as high throughput screenings to isolate Tetraselmis mutants impaired in photosymbiotic relationship. This proposal offers a major breakthrough for exploring marine photosymbioses in particular in the light of oxygen as a key component driving photosymbiosis.