Genomic Characterization and New Species Identification of Winogradskyella with Comparative Analysis of Polysaccharide Utilization Loci

Marine macroalgae convert a substantial fraction of fixed carbon dioxide into various polysaccharides. Winogradskyella is a genus within the phylum Bacteroidota with a clear marine origin especially from marine macroalgae. Most members of this genus have been found associated with macroalgae or microalgae. Using a combination of genomic, phylogenetic, and biochemical approaches, we characterized five novel Winogradskyella species capable of degrading marine macroalgal polysaccharides. Bioinformatic PUL annotations suggest usage of a large array of polysaccharides, including laminarin, -glucans, and alginate as well as mannose- and fucose-, highlighting the genus involvement in the marine carbon cycle. Many of the PULs exhibit new genetic architectures and suggest substrates rarely described for marine environments. Using the SusC/D trees, we analyzed evolutionary relationships of SusC/D homologs and found indications for profound changes in microbial utilization of laminarin, alginate, -glucans, {beta}-mannan, and sulfated xylan. Through the genomic study and annotation of PULs, we explored the complex relationship between genome size and polysaccharide degradation potential of Winogradskyella. These findings underscore the ecological significance of Winogradskyella in marine ecosystems and their role in polysaccharide degradation, providing a basis for biogeochemical cycling and future biotechnological applications.