Phototaxis in Cyanobacteria: From Mutants to Models of Collective Behavior

Cyanobacteria rely on photosynthesis, and thus have evolved complex responses to light. These include phototaxis, the ability of cells to sense light direction and move towards or away from it. Analysis of mutants has demonstrated that phototaxis requires the coordination of multiple photoreceptors and signal transduction networks. The output of these networks is relayed to type IV pili (T4P) that attach to and exert forces on surfaces or other neighboring cells to drive twitching or gliding motility. This, along with the extrusion of polysaccharides or slime by cells, facilitates the emergence of group behavior. We evaluate recent models that describe the emergence of collective colony-scale behavior from the responses of individual, interacting cells. We highlight the advantages of active matter approaches in the study of bacterial communities, discussing key differences between emergent behavior in cyanobacterial phototaxis and similar behavior in chemotaxis or quorum sensing.

Automated summary

Cyanobacteria rely on photosynthesis and have evolved complex responses to light, including phototaxis and group behavior. By coordinating multiple photoreceptors and signal transduction networks, cyanobacteria can sense light direction and move towards it. Through the connection and force exertion of T4P, cyanobacteria can drive twitching or gliding motility on surfaces or neighboring cells, facilitating the emergence of collective behavior.