PT  - JOURNAL ARTICLE
AU  - Anna Dragoš
AU  - Nivedha Lakshmanan
AU  - Marivic Martin
AU  - Balázs Horváth
AU  - Gergely Maróti
AU  - Carolina Falcón García
AU  - Oliver Lieleg
AU  - Ákos T. Kovács
TI  - Evolution of exploitative interactions during diversification in <em>Bacillus subtilis</em> biofilms
AID  - 10.1101/173476
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 173476
4099  - http://biorxiv.org/content/early/2017/08/09/173476.short
4100  - http://biorxiv.org/content/early/2017/08/09/173476.full
AB  - One sentence summary Evolution of Bacillus subtilis pellicle biofilms results in diversification into distinct colony variants that profoundly differ in biofilm-related features and in social roles they play in mixed pellicles.ABSTRACT Microbial biofilms are tightly packed, heterogeneous structures that serve as arenas for social interactions. Studies on Gram negative models reveal that during evolution in structured environments like biofilms, isogenic populations commonly diversify into phenotypically and genetically distinct variants. These variants can settle in alternative biofilm niches and develop new types of interactions that greatly influence population productivity. Here, we explore the evolutionary diversification of pellicle biofilms of the Gram positive, spore-forming bacterium Bacillus subtilis. We discover that - similarly to other species - B. subtilis diversifies into distinct colony variants. These variants dramatically differ in biofilm formation abilities and expression of biofilm-related genes. In addition, using a novel quantitative approach, we reveal striking differences in surface complexity and hydrophobicity of the evolved colony types. Interestingly, one of the morphotypes completely lost the ability of independent biofilm formation and evolved to hitchhike with other morphotypes with improved biofilm forming abilities. Genome comparison suggests that major phenotypic transformations between the morphotypes can be triggered by subtle genetic differences. Our work demonstrates how positive complementarity effects and exploitative interactions intertwine during evolutionary diversification in biofilms.