The ‘fight or flight’ response to fight against or to escape from perceived danger is essential for animal survival. But interestingly, microorganisms can adopt similar strategies. Rather than working alone, individuals of the same species can show different behaviours or so-called phenotypic heterogeneity. Through coordinated action, they work together to increase the chance of species survival.

A recent study by López-Pagán and colleagues focuses on the adaptive response of the notorious plant bacterial pathogen Pseudomonas syringae during infection. At the heart of this story are two bacterial traits: the type III secretion system (T3SS), which is a nanomachine that is responsible for the injection of immune-suppressing effectors into plant cells, and the bacterial flagellum, which is a tail-like structure for movement. Using advanced microscopy coupled with dual-fluorescent reporters and flow cytometry, the authors dissect the spatiotemporal distribution of bacterial subpopulations during infection and their corresponding dynamics of gene expression.