A putative GtrB-like glycosyltransferase modulates cation-dependent BCP8-2 phage infection and cell surface structure...

Bacillus cereus is a foodborne pathogen of growing concern due to its persistence and antimicrobial resistance. To identify host determinants influencing susceptibility to phage BCP8-2, a mini-Tn10 transposon mutant library of B. cereus ATCC 14579 was constructed and screened for altered phage susceptibility. A mutant (BC2012) showing partial resistance carried an insertion in BC_RS27090 (previously BC_5432), encoding a putative GtrB-like bactoprenol glycosyltransferase. Complementation restored phage sensitivity, confirming its functional involvement. The mutant showed a slight reduction in efficiency of plating, whereas, adsorption assay revealed significantly reduced phage binding and infectivity, particularly under cation-rich conditions. Furthermore, adsorption kinetics and one-step growth curve in mutant supported that gtrB mutation affects initial adsorption. Microscopy showed altered surface morphology with thinner, smoother cell walls. These data indicate that gtrB affects surface properties essential for cation-dependent phage adsorption and infection and provide a foundation for future studies on the role of surface glycosylation and ionic interactions in Gram-positive phage biology.IMPORTANCEPathogenic Bacillus cereus is resilient across diverse environments and produces diverse toxins linked to foodborne outbreaks. Bacteriophages provide an effective strategy to control B. cereus; however, molecular targets of phage-host interaction are poorly understood, limiting the effective phage-based control. The current study addresses this gap by identifying a putative bactoprenol glycosyltransferase (GtrB), a viral factor in phage BCP8-2 susceptibility. Data obtained highlight a partial reduction of phage infection in the gtrB mutant, demonstrating that GtrB-like glycosyltransferase significantly contributes to BCP8-2 phage infection and adsorption. Our findings provide significant insights into advancing phage therapy, antibiotic resistance, and B. cereus biocontrol in food and clinical settings.