CRISPR-Cas Systems: Bridging Bacterial Immunity and Host Interactions

The CRISPR-Cas system is one of the most versatile and adaptive defense mechanisms in prokaryotes, facilitating sequence-specific identification and neutralization of invading genetic elements, such as bacteriophages and plasmids. Beyond their primary function in adaptive immunity, accumulating evidence indicates that CRISPR-Cas systems are intricately integrated into bacterial physiology and involve processes such as gene regulation, stress response, biofilm dynamics, quorum-sensing pathways, and virulence modulation. These functions underscore the multifaceted role of CRISPR-Cas in bacterial survival, persistence, and host-pathogen interactions. Moreover, the horizontal transfer and evolutionary diversification of CRISPR-Cas systems underscores their significance in shaping microbial communities and facilitating co-evolutionary interactions with phages. The translational potential of these systems extends well beyond microbial immunity and offers promising applications in microbiome engineering, antimicrobial development, and precision medicine. This review synthesizes the current knowledge on the regulatory and adaptive roles of CRISPR-Cas, highlighting their dual function as protectors of genomic integrity and modulators of host interactions.