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, α-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, α-glucans, β-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.