Mechanical Regulation of Photosynthesis

Photosynthesis is regulated in response to many diverse stimuli including light intensity and wavelength, nutrient availability, and temperature to prevent formation of reactive oxygen species and cell death. However, it has remained a challenge to investigate this regulation in the context of a living photosynthetic cell due to the heterogeneity inherent to batch culture analysis. To overcome this obstacle, we utilized long-term, quantitative time-lapse fluorescence microscopy to visualize the growth and subcellular dynamics of individual wildtype and mutant cyanobacterial cells over multi-generational lineages. Our results demonstrate that in addition to known abiotic regulators of photosynthesis, mechanical perturbations lead to attenuation of photosynthesis and can play a major role in governing cellular fitness and productivity in cyanobacteria. These results provide insight into how photosynthetic organisms navigate the physical environment and a new perspective on source-sink regulation of photosynthesis that incorporates conversion of light into mechanical energy.