一株新型溶藻弧菌噬菌体φV039C的生物学特性和全基因组分析

Biological Characteristics and Genome Analysis of a New Vibrio alginolyticus Phage φV039C

对一株溶藻弧菌噬菌体φV039C进行了生物学特性和全基因组序列的研究。经透射电镜观察可见,噬菌体φV039C头部为正廿面体结构,直径58.9 nm,具长105.2 nm的尾部;采用双层平板法检测,其最佳感染复数为0.1;通过一步生长曲线计算可得,噬菌体φV039C的潜伏期为20 min,爆发期为10 min,裂解量为163 pfu/cell;利用第三代单分子测序平台进行全基因组测序分析,其基因组全长43405 bp,G+C含量为42.95%,74个开放阅读框(ORF)主要为噬菌体的结构、DNA复制和裂解有关的基因;在NCBI数据库中进行基因组比对,发现与其最接近的长尾噬菌体科的溶藻弧菌噬菌体NF和副溶血弧菌噬菌体Seahorse的覆盖率仅为11%(覆盖区域的相似度分别为92.2%和93.3%),此外,基于裂解酶构建的系统进化树也表明,φV039C与二者处于距离最近的分支。由此得出,溶藻弧菌噬菌体φV039C是一株新型的噬菌体,分类上应归属有尾噬菌体目长尾噬菌体科。

In this paper,the biological characteristics and the whole genome sequence of V.alginolyticus phageφV039C were studied.Through transmission electron microscopy,φV039C was observed to have an icosahedral head with diameter of 58.9 nm,and a tail with length of 105.2 nm.Using the double-layer plate method,its optimal multiplicity of infection(MOI)was detected to be 0.1.One-step growth curve showed that the latent period was 20 min,the burst period was 10 min,and the burst size was 163 pfu/cell.Phage genome was sequenced using the PacBio sequencing platform.The length of the whole genome ofφV039C is 43405 bp with G+C of 42.95%.And 74 open reading frames(ORFs)were annotated,including genes related to DNA replication,structure and lysis.The query of the whole genome ofφV039C in NCBI database indicated that Vibrio alginolyticus phage NF and Vibrio parahaemolyticus phage seahorse had the both low coverage of 11%with identity of 92.2%and 93.3%,respectively.In addition,the phylogenetic tree based on lyase also showed thatφV039C was nearest to the two phages.In summary,φV039C is a novel bacteriophage,which belongs to Caudovirales,Siphoviridae.