Novel Erwinia persicina Infecting Phage Midgardsormr38 Within the Context of Temperate Erwinia Phages.

Nikita Zrelovs,Andris Dislers,Andris Kazaks

doi:10.3389/fmicb.2020.01245

Nikita Zrelovs, Andris Dislers + Show 1 more

Open Access

https://doi.org/10.3389/fmicb.2020.01245

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Abstract

Prophages or prophage remnants are found in chromosomes of many bacterial strains and might increase the environmental fitness and/or virulence of their hosts. Up to this date, complete genome sequences of only seven temperate bacteriophages infecting bacteria from genus Erwinia, comprising of mostly phytopathogenic bacteria, are available publicly. No attempts to analyze the global diversity of temperate Erwinia phages and establish relationships between cultured temperate Erwinia phages and prophages were yet made. In this study, we have isolated, sequenced, and described novel Erwinia persicina infecting bacteriophage “Midgardsormr38” and placed it in the context of previously described Erwinia sp. temperate phages and putative prophages derived from chromosomes of publicly available complete genomes of Erwinia sp. to broaden and investigate diversity of temperate Erwinia phages based on their genomic contents. The study revealed more than 50 prophage or prophage remnant regions in the genomes of different Erwinia species. At least 5 of them seemed to be intact and might represent novel inducible Erwinia phages. Given the enormous bacteriophage diversity, attempts to establish evolutionary relationships between temperate Erwinia phages revealed at least five different clusters of temperate phages sharing higher degree of similarity.

Highlights

Bacteriophages, shortly phages—viruses of bacteria, the most abundant biological entities known to man—are omnipresent in every natural habitat where bacteria thrive (Clokie et al, 2011)
Successful infection of the susceptible host by lytic bacteriophage almost certainly results in lysis of the host cell and release of phage progeny capable of further infections into the surrounding environment (Young, 1992), whereas infection by a lysogenic phage might result in incorporation of phage nucleic acid into the genome of its host as either part of its chromosome or in the form of an episome (Utter et al, 2014; Howard-Varona et al, 2017)
Prophages residing in genomes of bacteria, can be induced to enter the lytic pathway leading to bacterial lysis and release of progeny (Mackey et al, 2016)

Summary

INTRODUCTION

Bacteriophages, shortly phages—viruses of bacteria, the most abundant biological entities known to man—are omnipresent in every natural habitat where bacteria thrive (Clokie et al, 2011). The majority of the so far observed phages belong to the viral order Caudovirales, comprising tailed double-stranded DNA containing bacteriophages (Ackermann, 2009) Based on their life cycle, most of the bacteriophages can be divided into two major groups, lytic and temperate phages. Despite the possibility of engineering virulent derivatives of temperate phages incapable of lysogenizing their host, considerably larger efforts were and are being made to explore the diversity of naturally lytic phages due to easier possibility of their use in biocontrol, leaving temperate phages of many bacterial taxa in their shadow. We report characterization and complete genome sequence of novel temperate E. persicina infecting phage Midgardsormr and try to broaden our knowledge on the diversity and evolutionary relationships of cultured and putative temperate Erwinia bacteriophages, which were largely ignored in the literature, apart from a few exceptions, either in papers describing novel temperate Erwinia phages or as an accessory part of a broader phage group analyses (Grose and Casjens, 2014; Sharma et al, 2019; Thompson et al, 2019)

MATERIALS AND METHODS

RESULTS AND DISCUSSION

DATA AVAILABILITY STATEMENT

CONCLUSION