Abstract
Bacteriophages, or phages, depend on their bacterial hosts for proliferation, leading to a coevolutionary relationship characterized by on-going arms races, where bacteria evolve diverse antiphage defense systems. The development of in silico methods and high-throughput screening techniques has dramatically expanded our understanding of bacterial antiphage defense systems, enormously increasing the known repertoire of the distinct mechanisms across various bacterial species. These advances have revealed that bacterial antiphage defense systems exhibit a remarkable level of complexity, ranging from highly conserved to specialized mechanisms, underscoring the intricate nature of bacterial antiphage defense systems. In this review, we provide a concise snapshot of antiphage defense research highlighting two preponderantly commandeered approaches and classification of the known antiphage defense systems. A special focus is placed on the model bacterial pathogen, Pseudomonas aeruginosa in antiphage defense research. We explore the complexity and adaptability of these systems, which play crucial roles in genome evolution and adaptation of P. aeruginosa in response to an arsenal of diverse phage strains, emphasizing the importance of this organism as a key emerging model bacterium in recent antiphage defense research.