Temperate bacteriophages as regulators of host behavior

•Lysogeny provides a unique state that promotes bacterial-phage mutualistic interactions.•Temperate phages regulate bacterial gene expression and behavior.•Phages are key players in bacterial virulence, biofilm formation, cold adaptation and more.

Bacteriophages are ubiquitous and affect most facets of life, from evolution of bacteria, through ecology and global biochemical cycling to human health. The interactions between phages and bacteria often lead to biological novelty and an important milestone in this process is the ability of phages to regulate their host's behavior. In this review article, we will focus on newly reported cases that demonstrate how temperate phages regulate bacterial gene expression and behavior in a variety of bacterial species, pathogenic and environmental. This regulation is mediated by diverse mechanisms such as transcription factors, sRNAs, DNA rearrangements, and even controlled bacterial lysis. The outcome is mutualistic relationships that enable adaptively enhanced communal phage-host fitness under specific conditions.