Photosynthetic Function

  • Light Harvesting and Photoprotection: The lab studies how algae harvest light and protect themselves from photodamage, focusing on mechanisms like non-photochemical quenching (NPQ) active in both green algae and diatoms. We investigate the expression and role of NPQ-related proteins such as LHCX and LHCSR in marine algae and green lineage, respectively. Our research further aims to characterize the situation when photosynthesis regulation and photoprotection are overpowered resulting in Photosystem II photoinhibition. The mechanism of this detrimental event is of central interest of the EU-funded PHOTONICS project (Photoinhibition: Nature of the process, and Influence on primary productivity Across Scales).
  • Electron and Ion Transport: Our research focuses on the structure-function relationships in photosynthetic complexes – in particular, in Photosystem II and cytochrome b6f – and on the regulation of electron transport pathways, including alternative pathways in diatoms. The HemeMotion project, launched together with CEA Cadarache, focuses on the molecular mechanisms of electron transfer in the electronic hub of photosynthesis, cytochrome b6f. The lab further aims to understand the interplay between state transitions and cyclic electron flow around Photosystem I, a topic we are involved in for the past two decades
  • Comparative Physiology: The lab explores the diversity of photosynthetic mechanisms across different phyla, mostly in primary and secondary endosymbionts. Our interests range from the characterization of regulators of photosynthesis, to the evolution and adaptation of phototrophy to various environments. We have now succeeded in obtaining the first mutant of an essential photosynthetic gene in our model system Cyclotella cryptica. Our long-term goal is to build on this and to generate a collection of mutants by CRISPR-Cas9 affecting all the nuclear-encoded, plastid-localized genes. Using mutants will dramatically broaden our understanding of marine algae physiology: of particular interest for us is how polar diatoms enter a quiescent state during prolonged darkness, and conversely, the resistance of organisms from different phyla to intense light conditions (see also theme3).