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. 2020 Sep 30;9(10):663.
doi: 10.3390/antibiotics9100663.

From Orphan Phage to a Proposed New Family-the Diversity of N4-Like Viruses

Johannes Wittmann  1 , Dann Turner  2 , Andrew D Millard  3 , Padmanabhan Mahadevan  4 , Andrew M Kropinski  5   6 , Evelien M Adriaenssens  7
Affiliations

From Orphan Phage to a Proposed New Family-the Diversity of N4-Like Viruses

Johannes Wittmann et al. Antibiotics (Basel). .

Abstract

Escherichia phage N4 was isolated in 1966 in Italy and has remained a genomic orphan for a long time. It encodes an extremely large virion-associated RNA polymerase unique for bacterial viruses that became characteristic for this group. In recent years, due to new and relatively inexpensive sequencing techniques the number of publicly available phage genome sequences expanded rapidly. This revealed new members of the N4-like phage group, from 33 members in 2015 to 115 N4-like viruses in 2020. Using new technologies and methods for classification, the Bacterial and Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) has moved the classification and taxonomy of bacterial viruses from mere morphological approaches to genomic and proteomic methods. The analysis of 115 N4-like genomes resulted in a huge reassessment of this group and the proposal of a new family "Schitoviridae", including eight subfamilies and numerous new genera.

Keywords: ICTV; N4; Schitoviridae; bacterial viruses; bacteriophages; virus taxonomy.

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Conflict of interest statement

With the exception of P.M. all authors are members of the Bacterial and Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV).

Figures

Figure 1
Figure 1
Genome structure of Escherichia phage N4 (70,153 bp) visualized by EasyFig [7].
Figure 2
Figure 2
ViPTree analysis of N4-like viruses with related podoviruses. Results were visualized with iTol. Viruses were assigned and marked according to the official ICTV classification with the outer and inner rings representing classification at the subfamily and family level, respectively. Non-marked viruses have not been classified yet.
Figure 3
Figure 3
VConTACT2 network analysis. Members of the proposed “Schitoviridae” family are marked in red.
See this image and copyright information in PMC

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