The landscape of bacterial contractile injection systems across large-scale metagenomes

Overall, this study expands our understanding of the ecological diversity, evolutionary adaptations, and functional roles of contractile injection systems (CISs) in microbial communities. The findings particularly highlight their adaptations to human-associated microbiomes. In addition, we conducted preliminary functional studies targeting the cargo protein BDI_2459 in <i>CIS</i> from <i>Parabacteroides distasonis</i> (CIS^Pd). These results provide new insights into CIS-mediated bacterial interactions and pave the way for future microbiome engineering and antibacterial strategies.