Chemotaxis strategies of bacteria with multiple run modes in complex environments

Elucidating the principles of bacterial motility and navigation is key to understand many important phenomena such as the spreading of infectious diseases. One of the prime challenges of swimming bacteria is to purposefully navigate to find food or flee from poisons in their natural habitat, e.g. the soil, which constitutes a complex, structured environment. Many bacterial species were recently reported to exhibit several distinct swimming modes—the flagella may, for example, push the cell body or wrap around it [1]. How do the different run modes shape the chemotaxis strategy of a multimode swimmer in complex environments? Here, we discuss the chemotactic motion of the bacterium Pseudomonas putida as a model organism [2]. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.

[1] M. Hintsche et al. Sci. Rep. 7 (2017)
[2] Z. Alirezaeizanjani et al. Sci. Adv. 6 (2020)