Bacillus subtilis operon encoding a membrane receptor for bacteriophage SPP1.

Area of Science:

• Microbiology
• Molecular Biology
• Bacteriophage Research

Background:

• Bacteriophage SPP1 interacts with Bacillus subtilis, but the specific receptor and binding mechanism remain incompletely understood.
• Identifying phage receptors is critical for understanding host-phage interactions and developing phage-based applications.

Purpose of the Study:

• To identify the essential gene responsible for irreversible binding of bacteriophage SPP1 to Bacillus subtilis.
• To elucidate the role of the yueB gene and its associated operon in the phage infection cycle.

Main Methods:

• Genetic complementation experiments using a xylose-inducible yueB copy.
• Gene disruption via pMutin4 insertion to assess phage resistance.
• Analysis of yueB operon mutants and their effect on phage adsorption and plaque morphology.
• Immunoblotting to detect YueB protein and potential processed forms.

Main Results:

• The yueB gene was identified as essential for irreversible bacteriophage SPP1 binding to Bacillus subtilis.
• Disruption of yueB conferred phage resistance, confirming its role as a receptor.
• Mutations in the yukE operon, while retaining yueB function, resulted in smaller plaque sizes without affecting adsorption rates, suggesting a post-adsorption role.
• YueB is a membrane protein, and its homologues are widespread in gram-positive bacteria.

Conclusions:

• YueB is the first demonstrated membrane-bound protein acting as a phage receptor in Bacillus subtilis.
• The yukE operon plays a role in a stage subsequent to irreversible phage adsorption, potentially impacting phage propagation.
• These findings advance the understanding of bacteriophage-host interactions and receptor identification in bacteria.