Biofilm spatial structure and superinfection immunity modulate inter-phage competition

Area of Science:

• Microbiology
• Ecology
• Systems Biology

Background:

• Phages exhibit lytic or temperate life cycles, with implications for host interaction.
• Biofilm environments present unique spatial constraints not fully explored in phage strategy research.

Purpose of the Study:

• To investigate how biofilm architecture influences the ecological success of lytic versus temperate phage infection strategies.
• To understand phage-host dynamics at a single-cell level within three-dimensional bacterial biofilms.

Main Methods:

• Development of a live imaging system for tracking phage infections in Escherichia coli biofilms.
• Single-cell resolution analysis of lytic infections, lysogenic infections, and uninfected cells.
• Competition assays between lysogenized bacteria and obligately lytic phages within biofilms.

Main Results:

• Biofilm structure significantly affects the ecological success of different phage infection strategies.
• Lysogenic infections are favored in densely packed biofilms where phage mobility is limited.
• Matrix-replete biofilms restrict lytic phage infection, promoting lysogenic growth and vertical phage genome transmission.
• Spatial structure and superinfection potential critically influence phage competition outcomes in biofilms.

Conclusions:

• Biofilm architecture can constrain lytic phage infection, favoring temperate phages utilizing the lysogenic cycle.
• Temperate phages can leverage biofilm interiors for progeny release, with outcomes dependent on diffusion limitations.
• The study highlights the importance of spatial ecology in shaping phage evolution and bacterial population dynamics.