Phages Isolated from Industrial Dairy Plants-from Physiological to Genomic Analyses.

(formerly c2) bacteriophages are among the three most prevalent phage types reported in dairy environments. Phages from this group conduct a strictly lytic lifestyle and cause substantial losses during milk fermentation processes, by infecting lactococcal host starter strains. Despite their deleterious activity, there are limited research data concerning phages. To advance our knowledge on this specific phage group, we sequenced and performed a comparative analysis of 10 new phages isolated from distinct dairy environments. Host range studies allowed us to distinguish the differential patterns of infection of cells for each phage, and revealed a broad host spectrum for most of them. We showed that 40% of the studied phages can infect both and strains. A preference to lyse strains with the C-type cell wall polysaccharide genotype was observed. Phage whole-genome sequencing revealed an average nucleotide identity above 80%, with distinct regions of divergence mapped to several locations. The comparative approach for analyzing genomic data and the phage lytic spectrum suggested that the amino acid sequence of the -encoded putative tape measure protein correlates with host range. Phylogenetic studies revealed separation of the sequenced phages into two subgroups. Finally, we identified three types of phage origin of replication regions, and showed they are able to support plasmid replication without additional phage proteins.