Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
Department of Microbiology, University of Kelaniya, Sri Lanka.
Can J Microbiol. 2021 Feb;67(2):147-160. doi: 10.1139/cjm-2020-0281. Epub 2020 Sep 9.
phage vB_MloS_Cp1R7A-A1 was isolated from soil planted with chickpea in Saskatchewan. It is dissimilar in sequence and morphology to previously described rhizobiophages. It is a B3 morphotype virus with a distinct prolate capsid and belongs to the tailed phage family . Its genome has a GC content of 60.3% and 238 predicted genes. Putative functions were predicted for 57 genes, which include 27 tRNA genes with anticodons corresponding to 18 amino acids. This represents the highest number of tRNA genes reported yet in a rhizobiophage. The gene arrangement shows a partially modular organization. Most of the structural genes are found in one module, whereas tRNA genes are in another. Genes for replication, recombination, and nucleotide metabolism form the third module. The arrangement of the replication module resembles the replication module of Enterobacteria phage T5, raising the possibility that it uses a recombination-based replication mechanism, but there is also a suggestion that a T7-like replication mechanism could be used. Phage termini appear to be long direct repeats of just over 12 kb in length. Phylogenetic analysis revealed that Cp1R7A-A1 is more closely related to PhiCbK-like phages and other B3 morphotype phages than to other rhizobiophages sequenced thus far.
从萨斯喀彻温种植鹰嘴豆的土壤中分离到了噬菌体 vB_MloS_Cp1R7A-A1。它在序列和形态上与先前描述的根瘤噬菌体不同。它是一种 B3 形态病毒，具有独特的拉长衣壳，属于有尾噬菌体科。其基因组的 GC 含量为 60.3%，预测有 238 个基因。预测了 57 个基因的推定功能，其中包括对应 18 个氨基酸的 27 个 tRNA 基因。这代表了迄今为止报道的根瘤噬菌体中 tRNA 基因数量最多。基因排列显示出部分模块化组织。大多数结构基因位于一个模块中，而 tRNA 基因位于另一个模块中。复制、重组和核苷酸代谢的基因形成第三个模块。复制模块的排列类似于肠杆菌噬菌体 T5 的复制模块，这增加了它使用基于重组的复制机制的可能性，但也有迹象表明它可能使用 T7 样复制机制。噬菌体末端似乎是长度略超过 12kb 的长直接重复序列。系统发育分析表明，Cp1R7A-A1 与 PhiCbK 样噬菌体和其他 B3 形态噬菌体比迄今测序的其他根瘤噬菌体更密切相关。
