Carnegie Faculty Associate Seminar - Adrien Burlacot

Life depends on extracellular energy to support growth, reproduction, and survival. However, the availability of energetic vectors (i.e., organic carbon, light, reductant) is variable in Nature, and the proper balance of dynamic energy fluxes is required to ensure cell's health and organisms' fitness. Yet how the balance between the cell's energy supply and demand is achieved at the cellular level to survive and thrive in dynamic environments remains unclear. Arguably, the most versatile cell's bioenergetic network is the one of photosynthetic organisms since natural factors like canopy movement, clouds, or water mixing quickly and dynamically affect the amount of light energy available. In this talk, we will explore how photosynthetic cells maintain their energetic homeostasis in a dynamic environment using the model green microalgae Chlamydomonas reinhardtii. First, by developing an approach inspired by frequency-domain analysis, we show that various molecular players of the photosynthetic electron transport chain harbor a specific domain of energetic fluctuation frequency for which it can support the cell's energetic needs, which we term "bandwidth". Our findings reveal how the flexibility of the electron transport chain maintains bioenergetic homeostasis at all timescales in dynamic light conditions. As the dynamic balance of the cell's energy occurs at the cellular level, we further show how the development of systematic and genome-wide analyses of the response to light fluctuations allows us to describe the dynamic landscape of the bioenergetic network at the cellular level. We will further discuss the potential impacts of unravelling the dynamics of the cell's bioenergetic network for improving energy systems, food production, and the health of plants and humans.