Resumo

Phages infecting spoilage microorganisms have been considered as alternative biocontrol agents, and the study of their genomes is essential to their safe use in foods. UFV-P2 is a new Pseudomonas fluorescens-specific phage that has been tested for its ability to inhibit milk proteolysis. It belongs to the family Podoviridae and has a genome organization similar to that of phages PaP3 and LUZ24 which have recently been classified as Luz24likeviruses. In the present study, the phylogenetic tree and structural genome analysis lead us to propose the classification of the phage UFV-P2 in this genus. For comparative purposes at the genomic level EMBOSS Stretcher and progressive Mauve were employed; while at the proteomic level we used CoreGenes. Seventeen genomic reference sequences of phages were downloaded from GenBank and compared to UFV-P2 genome. For clustering UFV-P2 by a phylogenetic approach, a Neighbor-Joining (NJ) tree was calculated using MEGA and ClustalW. The analysis revealed that vb_PaeP_p2-10_Or1, vb_PaeP_C1-14_Or, LUZ24, PaP4, PaP3, MR299-2 and tf are the phages most closely related to UFV-P2, presenting genomic identities ranging from 49.5% to 57.5%. The genomes of these phages shared a set of conserved locally collinear blocks (LCB) that appear be free from genome rearrangements. Phages LUZ24, PaP4, and UFV-P2 present a conserved bidirectional genomic organization, which is showed by the seven shared LCBs. Phage tf also presents this organization, but with some differences in the shared LCBs. Phages MR299-2, PaP3, vb_PaeP_p2-10_Or1, and vb_PaeP_C1-14_Or present an inverted set of LCBs, representing an opposing arrangement of the gene modules. Proteins of these seven phages were the top hits with the UFV-P2 sequences and can collaborate with each other’s functional annotations. As suggested by the structural genomic comparisons, phylogenetic clustering of genomic sequences grouped the phages according the shared LCBs. Phages PaeP_p2-10_Or1, vb_PaeP_C1-14_Or, LUZ24, PaP4, PaP3, MR299-2, tf, and UFV-P2 were included in a distinct monophyletic clade in NJ phylogenetic tree, which possibly represents the Luz24likevirus genus. The shared LCBs may be considered as a genomic signature for this genus. Then, we propose the classification of the phage UFV-P2 in the Luz24likevirus genus.