Social evolution of shared biofilm matrix components

Area of Science:

• Microbiology and Evolutionary Biology
• Bacterial community dynamics
• Social evolution in microbes

Background:

• Biofilm formation is a widespread bacterial growth strategy crucial for adhesion.
• Diffusible matrix proteins act as public goods, benefiting multiple cells but are costly to produce.
• The evolutionary stability of producing these shared factors remains an open question.

Purpose of the Study:

• To investigate the evolutionary stability of producing diffusible biofilm matrix proteins.
• To identify factors influencing the susceptibility of these public goods to 'cheater' exploitation.
• To model the conditions under which costly public good production is evolutionarily stable in bacteria.

Main Methods:

• Utilized *Vibrio cholerae* as a model organism for studying biofilm formation.
• Analyzed the spatial structure of biofilms and the range of exploitation for diffusible proteins.
• Developed a mathematical model linking production costs, exploitation range, and spatial distribution to evolutionary stability.

Main Results:

• Diffusible biofilm matrix proteins are indeed susceptible to exploitation by non-producing cells ('cheaters').
• Evolutionary stability is contingent upon biofilm spatial structure, intrinsic sharing mechanisms, and environmental flow.
• Exploitation of diffusible adhesion proteins is spatially localized around producing cell clusters.

Conclusions:

• Production of diffusible biofilm matrix components is evolutionarily stable under conditions found in natural and host environments.
• The study introduces the concept of 'exploitation range' and associated analytical tools for studying bacterial cooperation.
• Findings are applicable to other secreted cooperative factors and public goods in microbial communities.