Physiological basis for photosymbiosis evolution

Tetrahymena thermophila (cilié) contenant des Chlorelles photosynthétiques, en microscopie à fluorescence (fluorescence de la chlorophylle).

Summary : Photosymbiosis was a key event for the expansion of life on Earth. The ability of eucaryotic cells to become photosynthetic through association with others photosynthetic eucaryotes evolved independently in several lineages of hosts (including metazoan such hydra, salamander and corals) with several different lineages of green or brown algae as symbionts. This recurrent evolution imply that a strong selective pressure exists for acquisition of photosynthesis and that the cellular features required for photosymbiosis establishment are widespread (possibly inherited from the last eukaryotic common ancestor). This strongly suggests that it is possible to engineer new photosymbiotic associations in the laboratory. In this project we will join state of the art cellular microbiology and live microscopy analysis (LCB, IAM team) with eucaryotic genetics (BIAM/LGBP team) to decipher the key cellular events and slection pressures leading to the evolution of photosymbiosis in simple eucaryotes.

Photography credits : Leone Espinoza/Gael Brasseur

Signature* : Christophe Robaglia LGBP/BIAM