Speaker
Description
Metabolic complementarity is hypothesized to underpin beneficial interactions between
symbiotic organisms, allowing the partners to potentially expand their combined metabolic capabilities by offsetting metabolic deficiencies. While genome-based metabolic models offer a promising avenue to predict such complementarity in silico, empirical evidence validating these predictions remains scarce. Here we analyzed 1300 algal-associated bacterial and 40 algal host genomes to investigate the specificity and evolution of metabolic complementarity. We addressed two key questions: 1) Does metabolic complementarity preferentially occur between algae and their direct bacterial associates compared to free-living relatives? and 2) To what extent is complementarity specific to host-bacterial pairs?
The comparative analysis of algal-associated and free-living bacteria did not consistently demonstrate enhanced metabolic complementarity in host-associated strains. However, we identified 38 bacterial taxa exhibiting significantly higher complementarity with their host or closely related algae compared to phylogenetically more distant relatives. Metabolic complementarity varied significantly across bacterial classes, with e.g. Bacteroidia displaying high levels of complementarity but low host specificity, while e.g. Gammaproteobacteria demonstrated greater host specificity. The precise metabolic exchanges underpinning these patterns are currently being explored. Our findings provide novel evidence supporting the co-evolution of metabolic complementarity between algal hosts and specific members of their microbiome.
