Arbitrium phages can manipulate each other’s lysis/lysogeny decisions

Many viruses can switch between lytic replication and dormancy (or lysogeny). It was recently discovered that some viruses that infect bacteria (known as bacteriophage or phage) employ peptide-based ("arbitrium") communication systems to optimize their lysis/lysogeny switch; high peptide concentrations signal a lack of susceptible hosts and trigger lysogeny, while low peptide concentrations signal an abundance of uninfected hosts and prompt lysis. Here, we demonstrate that arbitrium phages belonging to different species and genera can influence each other's infection dynamics by secreting similar communication peptides, leading to early lysogenization of the signal-receiving phage and elevated fitness of the signal-emitting phage. Antagonistic coevolution between signal-emitting and signal-receiving phages to manipulate each other's infection behaviors may explain the rapid diversification of arbitrium systems and their frequent horizontal exchange to escape the noise of crosstalk.