Genome sequencing of lytic and temperate phages infecting members of the Roseobacter clade

海洋细菌可能是地球上数量最多的生物，在主要的元素循环中起着关键的作用。它们作为生物实体的丰度只有感染它们的病毒（噬菌体）才能超过。细菌介导的有机和无机物转化对大气成分和气候调节具有重要意义。玫瑰杆菌群是海洋细菌的一个分支，通常在整个海洋中以高丰度发现，对大量培养代表的研究表明，这是一个生理多样化的群体。最近在沃里克分离到一株甲基卤化物（甲基溴和甲基氯）和DMSP降解菌株Roseovarius sp. 217，并对该菌株的基因组进行了测序。来自这一分支的菌株的进一步基因组序列现在可用，并允许在蛋白质组学和转录组学水平上更详细地研究这些生物体。海洋病毒通过裂解宿主细胞影响生物地球化学循环，将异养原生生物的碳流转移到溶解的有机物池中。最近，感染海洋蓝藻的噬菌体已被证明携带编码蓝藻光合反应中心蛋白质的基因。这些基因在病毒复制阶段表达，在海洋环境中构成病毒编码的光合作用。噬菌体感染无处不在的玫瑰杆菌分支（玫瑰噬菌体）成员可能会影响玫瑰杆菌进行生物地球化学循环的程度，但迄今为止这些噬菌体很少受到关注。我们分离了3个玫瑰噬菌体，其中1个感染了Roseovarius sp. 217，并拟对这3个噬菌体进行基因组测序。这将告诉我们这些噬菌体的特定特征，并将为我们提供有关它们的生活策略和进化的线索。目前尚不清楚这些基因组序列将告诉我们什么，但考虑到从噬蓝菌基因组中获得的令人兴奋的见解，并考虑到其宿主的丰度，遗传和生理多样性，本研究的结果将在玫瑰杆菌及其噬菌体的进化和生态学背景下提供非常丰富的信息，并很可能为我们提供令人兴奋的新见解。

Marine bacteria are probably the most abundant group of organisms on the planet and are of pivotal importance in the major elemental cycles. Their abundance as biological entities is only exceeded by the viruses (phages) that infect them. Bacterially mediated transformations of organic and inorganic matter have important implications for atmospheric composition and climate regulation. The Roseobacter group is a clade of marine bacteria that is commonly found at high abundance throughout the oceans, and studies of a large number of cultivated representatives have shown this to be a physiologically diverse group. A methyl halide (methyl bromide and methyl chloride) and DMSP degrading strain, Roseovarius sp. 217, has recently been isolated at Warwick and the genome of this strain has been sequenced. Further genome sequences of strains from this clade are available now and allow to study these organisms in more detail at the proteomic and transcriptomics level. Marine viruses influence biogeochemical cycles through lysis of host cells, diverting carbon flow from heterotrophic protists into the pool of dissolved organic matter. Recently, phages infecting marine cyanobacteria have been shown to carry genes that encode proteins of the photosynthetic reaction centre of cyanobacteria. These genes were expressed during the phase of virus replication constituting virus-encoded photosynthesis in the marine environment. Phages infecting members of the ubiquitous Roseobacter clade (roseophages) may affect the extent of biogeochemical cycling carried out by Roseobacters, but these phage have received little attention until now. We have isolated three roseophages, including one that infects Roseovarius sp. 217, and propose to sequence the genomes of these three phages. This will inform us of particular features of these phage and will give us clues about their life strategy and evolution. It is not clear what these genome sequences will tell us, but given the exciting insights from cyanophage genomes, and considering the abundance, genetic and physiologic diversity of their hosts, the outcomes of this research will be very informative in the context of the evolution and ecology of Roseobacters and their phages and are very likely to give us exciting new insights into the properties of roseophages.