School of Food Science & Engineering, Ocean University of Chinagrid.4422.0, Qingdao, Shandong Province, China.
Appl Environ Microbiol. 2022 Sep 13;88(17):e0089522. doi: 10.1128/aem.00895-22. Epub 2022 Aug 15.
The high host specificity of phages is a real challenge in the therapy applications of the individual phages. This study aimed to edit the long tail fiber proteins () of a T5-like phage to obtain the engineered phages with expanded plaquing host range. Two T5-like Salmonella phages with high genome sequence homology but different plaquing host ranges, narrow-host range phage vB STyj5-1 (STyj5-1) and wide-host range phage vB BD13 (BD13), were isolated and characterized. The parts of STyj5-1 were replaced by the corresponding part of BD13 using homologous recombination method to obtain the engineered phages. The alterations of the whole part or the N-terminal amino acids 1-400 of of STyj5-1 could expand their plaquing host ranges (from 20 strains to 30 strains) and improve their absorption rates (from 0.28-28.84% to 28.10-99.49%). Besides, the one-step growth curves of these engineered phages with modified parts were more similar to that of STyj5-1. The burst sizes of phages BD13, STyj5-1 and the engineered phages were 250, 236, 166, and 223 PFU per cell, respectively. The expanded plaquing host range and improved absorption rates of these engineered phages revealed that the part might be the primary determinant of the host specificities of some T5-like phages. Genetic editing can be used to change or expand the host range of phages and have been successfully applied in T2, T4 and other phages to obtain engineered phages. However, there are hardly any similar reports on T5-like phages due to that the determinant regions related to their host ranges have not been completely clarified and the editing of T5-like phages is more difficult compared to other phages. This study attempted and successfully expanded the host range of a narrow-host range T5-like phage (STyj5-1) by exchanging its whole part or the N-terminal 1-400aa of that part by a broad-host range phage (BD13). These demonstrated the part might be the primary determinant of the host specificities for some T5-like phages and provided an effective method of extension plaquing host range of these phages.
噬菌体的高宿主特异性是其在治疗应用中的一个真正挑战。本研究旨在编辑 T5 样噬菌体的长尾纤维蛋白（），以获得扩展噬菌斑宿主范围的工程噬菌体。本研究分离并鉴定了两株具有高基因组序列同源性但噬菌斑宿主范围不同的 T5 样沙门氏菌噬菌体，即窄宿主范围噬菌体 vB STyj5-1（STyj5-1）和宽宿主范围噬菌体 vB BD13（BD13）。采用同源重组的方法，用 BD13 的相应部分替换 STyj5-1 的部分，获得了工程噬菌体。STyj5-1 的整个部分或 N 端氨基酸 1-400 的改变可以扩大其噬菌斑宿主范围（从 20 株增加到 30 株）并提高其吸收率（从 0.28-28.84%提高到 28.10-99.49%）。此外，这些带有修饰部分的工程噬菌体的一步生长曲线与 STyj5-1 的更为相似。噬菌体 BD13、STyj5-1 和工程噬菌体的爆发大小分别为 250、236、166 和 223 PFU/细胞。这些工程噬菌体噬菌斑宿主范围的扩大和吸收率的提高表明，部分可能是一些 T5 样噬菌体宿主特异性的主要决定因素。遗传编辑可用于改变或扩大噬菌体的宿主范围，并已成功应用于 T2、T4 等噬菌体，以获得工程噬菌体。然而，由于与噬菌体宿主范围相关的决定区域尚未完全阐明，并且与其他噬菌体相比，T5 样噬菌体的编辑更为困难，因此几乎没有关于 T5 样噬菌体的类似报道。本研究尝试并成功地通过交换其整个部分或该部分的 N 端 1-400aa，用宽宿主范围噬菌体（BD13）扩展了窄宿主范围 T5 样噬菌体（STyj5-1）的宿主范围。这些结果表明，部分可能是一些 T5 样噬菌体宿主特异性的主要决定因素，并为扩展这些噬菌体的噬菌斑宿主范围提供了一种有效方法。
