Characterization of Novel Erwinia amylovora Jumbo Bacteriophages from Eneladusvirus Genus.

Sang Guen Kim,Hyoun Joong Kim,Jun Kwon,Se Chang Park,Sung Bin Lee,Eunjung Roh,Sib Sankar Giri,Jungkum Park

doi:10.3390/v12121373

Sang Guen Kim, Hyoun Joong Kim + Show 6 more

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https://doi.org/10.3390/v12121373

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Abstract

Jumbo phages, which have a genome size of more than 200 kb, have recently been reported for the first time. However, limited information is available regarding their characteristics because few jumbo phages have been isolated. Therefore, in this study, we aimed to isolate and characterize other jumbo phages. We performed comparative genomic analysis of three Erwinia phages (pEa_SNUABM_12, pEa_SNUABM_47, and pEa_SNUABM_50), each of which had a genome size of approximately 360 kb (32.5% GC content). These phages were predicted to harbor 546, 540, and 540 open reading frames with 32, 34, and 35 tRNAs, respectively. Almost all of the genes in these phages could not be functionally annotated but showed high sequence similarity with genes encoded in Serratia phage BF, a member of Eneladusvirus. The detailed comparative and phylogenetic analyses presented in this study contribute to our understanding of the diversity and evolution of Erwinia phage and the genus Eneladusvirus.

Highlights

Bacteriophages have recently been proposed as alternative treatments to mitigate bacterial diseases [1,2,3,4,5]
Most jumbo phages belong to the genus Myoviridae; some Siphoviridae bacteriophages that infect Caulobacter are registered in the public depository
The nucleus-like structure protein of Serratia jumbo phage PCH45 protects its genome from the defense system of bacteria, CRISPR-Cas, by surrounding its genome [21]

Summary

Introduction

Bacteriophages (phages) have recently been proposed as alternative treatments to mitigate bacterial diseases [1,2,3,4,5]. Since the disease seriously damages apple and pear farms, an effective alternative to antibiotics against E. amylovora is urgently required. Of the around 200 jumbo bacteriophage sequences currently reported, phages infecting gram-negative bacterial families in the order Enterobacterales account for a relatively high proportion (65 species). Most of these phages belong to the family Myoviridae, which has a genome size of 200–300 kb, and most species (29 species) are included in the genera Agricanvirus, Machinavirus, Erskinevirus, and Derbicusvirus, which share the same host (Erwinia) [4,12,13,14]. Among the dozens of jumbo phages having a genome size over 300 kb, only one phage shows infectivity towards Erwinia and closely related bacterial species [15]

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