Microbial interactions from a molecular and evolutionary perspective

Antagonistic bacterial interactions are common in biofilms where bacteria compete for limited space and nutrients. These interactions are conditioned by a number of factors related to the biofilm lifestyle like group effects, high intrinsic genetic – and phenotypic – diversity, strong kin competition and cooperation.

Whereas research on competitive interactions mostly focused in the characterization of antibiotic-like compounds, more recently a myriad of non-biocidal antagonistic molecules have been identified and the underlying molecular mechanisms have been characterized. Yet how microorganisms adapt and outcompete their conspecific neighbors in multispecies and high cell-density environments remains poorly studied.

After providing a brief overview of the diverse competition mechanisms within biofilms, I will focus on antibiofilm polysaccharides and their role in population dynamics. Finally, I will discuss adaptation mechanisms, including de novo emergence of interference competition, during long-term experimental evolution using soil-dwelling Myxococcus xanthus as a model organism.