Complete genome sequence of Alteromonas marina OM2201, a marine bacterium degrading Ulva prolifera polysaccharides isolated from surface of the Yellow Sea.

As a consequence of marine eutrophication, there has been an exponential growth of Ulva prolifera, culminating in the yearly emergence of a massive green tide along the shores of Qingdao. This phenomenon exerts a detrimental impact on the marine ecosystem. As reported, the expression level of Alteromonas enzymes involved in U. prolifera polysaccharides degradation is increased during the green tide outbreak period, potentially accelerating the breakdown of U. prolifera biomass. This enhanced degradation could facilitate the transition to the waning phase of the green tide event. In this study, strain Alteromonas marina OM2201 was isolated from seawater samples taken during an U. prolifera bloom in the coastal waters of Qingdao. Its genome contains a ring chromosome and two plasmids. The length of the circular chromosome was 4,489,073 bp with GC content of 44.21 mol%, and the length of plasmid 1 was 233,636 bp with GC content of 42.24 mol%, and the length of plasmid 2 was 5594 bp with GC content of 39.61 mol%. Genomic analysis showed that Alteromonas marina OM2201 contained a variety of ulvan lyase genes, indicating that it could promote the degradation of U. prolifera polysaccharides. This genetic makeup potentially enables the strain to expedite the decomposition of U. prolifera biomass. Therefore, this study broadens our understanding of the Alteromonas bacteria that can degrade U. prolifera polysaccharides during the outbreak period.