Lucilla Taddei

Molecular characterisation of diatom photo-acclimation and photo-protection mechanisms.

Diatoms are photosynthetic microorganisms living in marine and freshwater environments, that use light energy to synthetize carbon compounds from carbon dioxide and water, with the generation of oxygen. Thus, through their photosynthetic activity, diatoms contribute for about one quarter of the global primary productivity and 40% of O2 on Earth. Diatoms are able to grow and perform optimally in variable environments, and to cope with fast light and nutrients changes in moving waters. When the light absorbed exceeds the photosynthetic capacity, harmful Reactive Oxygen Species (ROS) can be generated. To avoid this, photosynthetic organisms can dissipate this energy as heat. The modulation of this process is fundamental for an efficient balance between survival and growth and a complete comprehension of it is still far from being achieved in these organisms.

It has been recently discovered that LHCX1 is a protein required for efficient light responses and growth, likely providing diatoms with a photosynthetic machinery capable of anticipating sudden changes in the underwater light field and offering a selective growth advantage in turbulent waters. In a dynamic environment like the Oceans, diatoms can also experience nutrient deprivation.  Three others LHCXs proteins are present in P. tricornutum and play a role in different moments of a diatom’s life, like the light absence and nutrients deprivation. I would like to understand the role of the different LHCXs proteins in the diatoms responses to these different external conditions.