Periodic Reporting for period 3 - ChloroMito (Chloroplast and Mitochondria interactions for microalgal acclimation)
Reporting period: 2023-01-01 to 2024-06-30
- What molecular mechanism(s) allow energy exchange between the two organelles?
- Are these mechanisms widely conserved in other oceanic taxa?
- Is this the solution adapted by phytoplankton to optimise their growth?
- Does it modulate the dynamic responses of phytoplankton to different integrated growth environments?
Overall, ChloroMito will change our understanding of oceanic photosynthesis, challenging concepts that are often deduced from plant-based concepts. This project will also generate new technologies suitable for the study of paradigm questions in photosynthesis beyond ChloroMito itself
The results published in Uwizeye et al. Nat Commun 2021 (phytoplankton subcellular architectures are modulated by energy management constraints) represent a major step in this direction. The discovery that environmental acclimation (the transition of the diatom Phaeodactylum from dim to bright light or the acclimation of Nannochloropsis to different trophic lifestyles) modulates cell volume occupancy by mitochondria and the plastid CO2-fixing compartment, while maintaining contacts between plastid mitochondria, provides the first pictures of phytoplankton acclimation at the cellular/subcellular level.
In the future, ChloroMito will continue to explore the structural/energetic constraint of phytoplankton acclimation, by combining cell biology/3D imaging (to decipher phytoplankton responses at subcellular scales), molecular biology (to identify the molecular actors of this subcellular energy exchange), biophysics (to validate these molecular actors by time-resolved spectroscopy) and ecophysiology (to compare the responses of evolutionarily distant phytoplankton taxa to environmental changes mimicking possible future ocean scenarios).