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DNA tandem repeats contribute to the genetic diversity of Brevibacterium aurantiacum phages
Author(s) -
Melo Alessandra G.,
Rousseau Geneviève M.,
Tremblay Denise M.,
Labrie Simon J.,
Moineau Sylvain
Publication year - 2020
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.15113
Subject(s) - biology , prophage , siphoviridae , genome , genetics , tandem repeat , integrase , genome size , virulence , gene , bacteriophage , escherichia coli
Summary This report presents the characterization of the first virulent phages infecting Brevibacterium aurantiacum , a bacterial species used during the manufacture of surface‐ripened cheeses. These phages were also responsible for flavour and colour defects in surface‐ripened cheeses . Sixteen phages (out of 62 isolates) were selected for genome sequencing and comparative analyses. These cos‐type phages with a long non‐contractile tail currently belong to the Siphoviridae family ( Caudovirales order). Their genome sizes vary from 35,637 to 36,825 bp and, similar to their host, have a high GC content (~61%). Genes encoding for an immunity repressor, an excisionase and a truncated integrase were found, suggesting that these virulent phages may be derived from a prophage. Their genomic organization is highly conserved, with most of the diversity coming from the presence of long (198 bp) DNA tandem repeats (TRs) within an open reading frame coding for a protein of unknown function. We categorized these phages into seven genomic groups according to their number of TR, which ranged from two to eight. Moreover, we showed that TRs are widespread in phage genomes, found in more than 85% of the genomes available in public databases.