Thanh Nguyen Cong, Nagayoshi Yuko, Fujino Yasuhiro, Iiyama Kazuhiro, Furuya Naruto, Hiromasa Yasuaki, Iwamoto Takeo, Doi Katsumi
Microbial Genetics Division, Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.
Plant Protection Research Institute, Hanoi, Vietnam.
Front Microbiol. 2020 Jun 3;11:885. doi: 10.3389/fmicb.2020.00885. eCollection 2020.
sp. M4 and other bacterial strains were isolated from plant soft rot disease. Virulent phages such as EspM4VN isolated from soil are trending biological controls for plant disease. This phage has an icosahedral head (100 nm in diameter), a neck, and a contractile sheath (100 nm long and 18 nm wide). It belongs to the Ackermannviridae family and resembles phage Ag3 and phages JA15 and XF4. We report herein that EspM4VN was stable from 10°C to 50°C and pH 4 to 10 but deactivated at 70°C and pH 3 and 12. This phage formed clear plaques only on sp. M4 among tested bacterial strains. A one-step growth curve showed that the latent phase was 20 min, rise period was 10 min, and an average of 122 phage particles were released from each absorbed cell. We found the phage's genome size was 160,766 bp and that it annotated 219 open reading frames. The genome organization of EspM4VN has high similarity with the phage SKML-39; phages Coodle, PP35, JA15, and Limestone; and phage Ag3. The phage EspM4VN has five tRNA species, four tail-spike proteins, and a thymidylate synthase. Phylogenetic analysis based on structural proteins and enzymes indicated that EspM4VN was identified as a member of the genus , subfamily Aglimvirinae, family Ackermannviridae.
M4菌株及其他细菌菌株是从植物软腐病中分离出来的。从土壤中分离出的诸如EspM4VN等烈性噬菌体正成为植物病害生物防治的研究热点。这种噬菌体有一个二十面体头部（直径100纳米）、一个颈部和一个收缩鞘（长100纳米，宽18纳米）。它属于艾氏噬菌体科，与噬菌体Ag3、噬菌体JA15和XF4相似。我们在此报告，EspM4VN在10°C至50°C以及pH值4至10的条件下稳定，但在70°C以及pH值3和12时失活。在测试的细菌菌株中，这种噬菌体仅在M4菌株上形成清晰的噬菌斑。一步生长曲线表明潜伏期为20分钟，上升期为10分钟，每个被吸附的细胞平均释放出122个噬菌体颗粒。我们发现该噬菌体的基因组大小为160,766碱基对，注释了219个开放阅读框。EspM4VN的基因组结构与噬菌体SKML - 39、噬菌体Coodle、PP35、JA15和石灰石噬菌体以及噬菌体Ag3具有高度相似性。噬菌体EspM4VN有五种tRNA种类、四种尾刺蛋白和一种胸苷酸合成酶。基于结构蛋白和酶的系统发育分析表明，EspM4VN被鉴定为艾氏噬菌体科Aglimvirinae亚科属的成员。
