Serena Flori

Elucidating the interplay between redox poising and remodelling of photosynthesis.

Phytoplankton is part of a wide network of microorganisms floating on water, which are essential for the Marine Ecosystem. Like plants, they use solar energy to absorb CO2 and produce oxygen via photosynthesis, and it is believed that phytoplankton contributes up to 50% of the overall O2 productivity and CO2 assimilation capacity on this planet. In a dynamic environment like the Oceans, light is a crucial factor, because it can change at different time and space scales depending on latitude, seasons, coverage of the sky, and water mixing. Therefore, Phytoplanktonic organisms must be able to optimize light absorption, utilization or dissipation, depending on the external conditions. During my PhD I am comparing the capacity of light utilization in two model organisms, a marine diatom Phaeodactylum tricornutum and a green microalgae Chlamydomonas reinhardtii. I would like to understand how light is used in the chloroplast (a specific cell structure responsible for photosynthesis). To achieve this, I am studying the structure of the chloroplast and the function of the proteins contained in this compartment under different environmental conditions, which I can reproduce in the laboratory. My aim is to build a general model of algae acclimation, describing how the environment modified the structure and function of the chloroplast, using structural, biochemical and modelling approaches.