Adhesion Strategies of <i>Chlamydomonas</i> in Heterogeneous Habitats

In contrast to marine phytoplankton, many photoactive microbes live in complex environments, such as liquid-infused soil and moist rocks, where they encounter and colonize a plethora of surfaces. We discovered that the adhesion of Chlamydomonas to surfaces can be reversibly switched on and off by light [1]. Our in vivo single-cell micropipette force spectroscopy experiments suggest that light-switchable adhesiveness is a natural functionality to actively regulate the transition between freely-swimming (planktonic) and surface-associated state, which yields an adhesive adaptation to optimize the photosynthetic efficiency of the cells in variable and inhomogeneous light conditions. Probing the adhesion forces on model substrates with tailored properties and dissecting the contributions from different intermolecular interactions reveal a universal protein-mediated adhesion mechanism that allows the cells to effectively colonize any type of abiotic surface in their heterogeneous natural habitats. Complementary to our single-cell force measurements, we characterize the surface colonization by cell adsorption assays from which we extract population level morphological and dynamical characteristics.
[1] Kreis et al., Nature Physics 14, 45-49 (2018).