Zhan Yuanchao, Huang Sijun, Voget Sonja, Simon Meinhard, Chen Feng
Institution of Marine and Environmental Technology, University of Maryland Center for Environmental Science, USA.
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
Sci Rep. 2016 Jul 27;6:30372. doi: 10.1038/srep30372.
Bacteria in the Roseobacter lineage have been studied extensively due to their significant biogeochemical roles in the marine ecosystem. However, our knowledge on bacteriophage which infects the Roseobacter clade is still very limited. Here, we report a new bacteriophage, phage DSS3Φ8, which infects marine roseobacter Ruegeria pomeroyi DSS-3. DSS3Φ8 is a lytic siphovirus. Genomic analysis showed that DSS3Φ8 is most closely related to a group of siphoviruses, CbK-like phages, which infect freshwater bacterium Caulobacter crescentus. DSS3Φ8 contains a smaller capsid and has a reduced genome size (146 kb) compared to the CbK-like phages (205-279 kb). DSS3Φ8 contains the DNA polymerase gene which is closely related to T7-like podoviruses. DSS3Φ8 also contains the integrase and repressor genes, indicating its potential to involve in lysogenic cycle. In addition, four GTA (gene transfer agent) genes were identified in the DSS3Φ8 genome. Genomic analysis suggests that DSS3Φ8 is a highly mosaic phage that inherits the genetic features from siphoviruses, podoviruses, prophages and GTAs. This is the first report of CbK-like phages infecting marine bacteria. We believe phage isolation is still a powerful tool that can lead to discovery of new phages and help interpret the overwhelming unknown sequences in the viral metagenomics.
由于玫瑰杆菌谱系中的细菌在海洋生态系统中具有重要的生物地球化学作用，因此已对其进行了广泛研究。然而，我们对感染玫瑰杆菌属的噬菌体的了解仍然非常有限。在此，我们报告一种新的噬菌体——噬菌体DSS3Φ8，它可感染海洋玫瑰杆菌鲁氏普罗威登斯菌DSS-3。DSS3Φ8是一种裂解性长尾噬菌体。基因组分析表明，DSS3Φ8与一组感染淡水细菌新月柄杆菌的长尾噬菌体CbK样噬菌体关系最为密切。与CbK样噬菌体（205 - 279 kb）相比，DSS3Φ8的衣壳较小，基因组大小也有所减小（146 kb）。DSS3Φ8含有与T7样短尾噬菌体密切相关的DNA聚合酶基因。DSS3Φ8还含有整合酶和阻遏基因，表明其有参与溶原周期的潜力。此外，在DSS3Φ8基因组中鉴定出四个基因转移因子（GTA）基因。基因组分析表明，DSS3Φ8是一种高度嵌合的噬菌体，它继承了来自长尾噬菌体、短尾噬菌体、原噬菌体和基因转移因子的遗传特征。这是关于CbK样噬菌体感染海洋细菌的首次报道。我们相信噬菌体分离仍然是一种强大的工具，它能够带来新噬菌体的发现，并有助于解读病毒宏基因组学中大量未知的序列。
