Rethinking the Evolution of Single-Stranded RNA (ssRNA) Bacteriophages Based on Genomic Sequences and Characterizations of Two R-Plasmid-Dependent ssRNA Phages, C-1 and Hgal1
Rethinking the Evolution of Single-Stranded RNA (ssRNA) Bacteriophages Based on Genomic Sequences and Characterizations of Two R-Plasmid-Dependent ssRNA Phages, C-1 and Hgal1
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DOI：
10.1128/jb.00929-12
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发表时间：
2012-09-01
影响因子：
3.2
通讯作者：
Wang, Ing-Nang
中科院分区：
文献类型：
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作者：
Kannoly, Sherin;Shao, Yongping;Wang, Ing-Nang
我们对两种依赖r质粒的单链RNA噬菌体（RPD ssRNA噬菌体）C-1和Hagl1进行了测序和表征。噬菌体C-1需要IncC组的共轭质粒，Hgal1需要IncH组的共轭质粒。测定了两种噬菌体的吸附速率常数和一步生长曲线。我们还通过实验证实了所预测的裂解基因的裂解功能。基因组测序和系统发育分析表明，这两种噬菌体都属于列文病毒类群，并且与另一种依赖于incp质粒的ssRNA噬菌体PRR1关系最密切。此外，我们的研究结果强烈表明，在列维病毒和异橄榄病毒中发现的基因组组织的典型包氏图早于结合质粒的噬菌体特化，这表明利用结合质粒进行细胞附着和进入是这两个主要的ssRNA噬菌体分支的独立进化事件。我们的研究结果也与先前的研究结果一致，即利维病毒样基因组组织是祖先的，异橄榄病毒样基因组是衍生的。为了更深入地了解ssRNA噬菌体的进化，需要更多的噬菌体专门用于各种共轭质粒和感染不同的细菌物种。
We have sequenced and characterized two R-plasmid-dependent single-stranded RNA bacteriophages (RPD ssRNA phages), C-1 and Hagl1. Phage C-1 requires a conjugative plasmid of the IncC group, while Hgal1 requires the IncH group. Both the adsorption rate constants and one-step growth curves are determined for both phages. We also empirically confirmed the lysis function of the predicted lysis genes. Genomic sequencing and phylogenetic analyses showed that both phages belong to the Levivirus group and are most closely related to another IncP-plasmid-dependent ssRNA phage, PRR1. Furthermore, our result strongly suggests that the stereotypical bauplans of genome organization found in Levivirus and Allolevivirus predate phage specialization for conjugative plasmids, suggesting that the utilization of conjugative plasmids for cell attachment and entry comprises independent evolutionary events for these two main clades of ssRNA phages. Our result is also consistent with findings of a previous study, making the Levivirus-like genome organization ancestral and the Allolevivirus-like genome derived. To obtain a deeper insight into the evolution of ssRNA phages, more phages specializing for various conjugative plasmids and infecting different bacterial species would be needed.