Synechococcus dominate picocyanobacterial communities in coastal environments. However, only a few Synechococcus phages have been described from the coastal seas of the Northwest Pacific Ocean. Here a new Synechococcus phage, S-B43 was isolated from the Bohai Sea, a semi-closed coastal sea of the Northwest Pacific Ocean. S-B43 is a member of Myoviridae, containing 275 predicted open reading frames. Fourteen auxiliary metabolic genes (AMG) were identified from the genome of S-B43, including five photosynthetic associated genes and several AMGs related to its adaption to the high turbidity and eutrophic coastal environment with a low ratio of phosphorus to nitrogen (HNLP). The occurrences of 31 AMGs among 34 cyanophage genomes indicates that AMGs zwf, gnd, speD, petF and those coding for FECH and thioredoxin were more common in coastal areas than in the open ocean and AMGs pebS and ho1 were more prevalent in the open ocean. The occurrence of cyanophage AMGs in different environments might be a reflection of the environmental adaption of their hosts. This study contributes to our understanding of the interactions between cyanobacteria and cyanophages and their environmental adaption to the coastal environment.

聚球藻在沿海环境中占主导地位的微微蓝藻群落。然而，在西北太平洋沿岸海域仅描述了少数聚球藻噬菌体。在这里，一种新的聚球藻噬菌体 S-B43 从西北太平洋的半封闭沿海海域渤海中分离出来。S-B43 是肌病毒科的成员，包含 275 个预测的开放阅读框。从 S-B43 的基因组中鉴定出 14 个辅助代谢基因 (AMG)，包括 5 个光合相关基因和几个与其适应低磷氮比 (HNLP) 的高浊度和富营养化沿海环境相关的 AMG。34 个噬蓝体基因组中 31 个 AMGs 的出现表明 AMGszwf、gnd、speD、petF以及编码 FECH 和硫氧还蛋白的那些在沿海地区比在公海更常见，AMG pebS和ho1在公海更普遍。噬蓝体AMGs在不同环境中的出现可能反映了宿主对环境的适应能力。这项研究有助于我们了解蓝藻和噬蓝体之间的相互作用及其对沿海环境的环境适应。