Small molecules as modulators of phage–bacteria interactions

Bacteriophages (phages) play a critical role in microbial ecology and evolution. Their interactions with bacteria are influenced by a complex network of chemical signals derived from a wide range of sources including both endogenous bacterial metabolites and exogenous environmental compounds. In this review, we highlight two areas where small molecules play a pivotal role in modulating phage behaviors. First, we discuss how temperate phages respond to various chemical cues that influence the lysis-lysogeny decision, describing recent advances in our understanding of noncanonical cues. Second, we examine the diverse array of small molecules that disrupt phage infection, potentially serving as bacterial defense strategies against their long-standing competitors. Collectively, this growing body of research highlights the intricate molecular mechanisms governing phage-bacteria dynamics, offering new perspectives on the chemical language shaping microbial communities.