TY - JOUR T1 - Model communities hint to promiscuous metabolic linkages between ubiquitous free-living freshwater bacteria JF - bioRxiv DO - 10.1101/103838 SP - 103838 AU - Sarahi L Garcia AU - Moritz Buck AU - Joshua J. Hamilton AU - Christian Wurzbacher AU - Magnus Alm Rosenblad AU - Katherine D. McMahon AU - Hans-Peter Grossart AU - Falk Warnecke AU - Alexander Eiler Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/01/28/103838.abstract N2 - Free-living microorganisms with streamlined genomes are very abundant in the environment. Genome streamlining results in losses in the cell’s biosynthetic potential generating physiological dependencies between microorganisms. However, there exists no consensus on the specificity of these microbial associations. To verify specificity and extent of these associations, mixed cultures were established from three different freshwater environments. These cultures contained free-living streamlined organisms lacking multiple biosynthetic pathways. Among the co-occurring members of the mixed cultures, there was no clear recurring pattern of metabolic complementarity and dependencies. This, together with weak temporal co-occurrence patterns observed using time-series metagenomics, suggests that free-living freshwater bacteria form loose and unspecific cooperative loops. Comparative genomics suggests that the proportion of accessory genes in populations of streamlined bacteria allows for flexibility in interaction partners. Altogether this renders these free-living bacterial lineages functionally versatile despite their streamlining tendencies. ER -