title: Functional and comparative genome analysis of novel virulent actinophages belonging to Streptomyces flavovirens.
abstract: Next Generation Sequencing (NGS) technologies provide exciting possibilities for whole genome sequencing of a plethora of organisms including bacterial strains and phages, with many possible applications in research and diagnostics. No Streptomyces flavovirens phages have been sequenced to date; there is therefore a lack in available information about S. flavovirens phage genomics. We report biological and physiochemical features and use NGS to provide the complete annotated genomes for two new strains (Sf1 and Sf3) of the virulent phage Streptomyces flavovirens, isolated from Egyptian soil samples.
  
  
  
  The S. flavovirens phages (Sf1 and Sf3) examined in this study show higher adsorption rates (82 and 85%, respectively) than other actinophages, indicating a strong specificity to their host, and latent periods (15 and 30 min.), followed by rise periods of 45 and 30 min. As expected for actinophages, their burst sizes were 1.95 and 2.49 virions per mL. Both phages were stable and, as reported in previous experiments, showed a significant increase in their activity after sodium chloride (NaCl) and magnesium chloride (MgCl2.6H2O) treatments, whereas after zinc chloride (ZnCl2) application both phages showed a significant decrease in infection. The sequenced phage genomes are parts of a singleton cluster with sizes of 43,150 bp and 60,934 bp, respectively. Bioinformatics analyses and functional characterizations enabled the assignment of possible functions to 19 and 28 putative identified ORFs, which included phage structural proteins, lysis components and metabolic proteins. Thirty phams were identified in both phages, 10 (33.3%) of them with known function, which can be used in cluster prediction. Comparative genomic analysis revealed significant homology between the two phages, showing the highest hits among Sf1, Sf3 and the closest Streptomyces phage (VWB phages) in a specific 13Kb region. However, the phylogenetic analysis using the Major Capsid Protein (MCP) sequences highlighted that the isolated phages belong to the BG Streptomyces phage group but are clearly separated, representing a novel sub-cluster.
  
  
  
  The results of this study provide the first physiological and genomic information for S. flavovirens phages and will be useful for pharmaceutical industries based on S. flavovirens and future phage evolution studies.
authors.affiliation: Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt. sharaf@paru.cas.cz.|Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 37005, České Budějovice, Czechia. sharaf@paru.cas.cz.
authors.forename: A
authors.identifier: 0000-0002-3436-9290
authors.initials: A
authors.lastname: Sharaf
authors.affiliation: Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR) of Italy, 90129, Palermo, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Mercati
authors.affiliation: Central Lab. of Organic Agriculture, Agricultural Research Center, Giza, 12619, Egypt.
authors.forename: I
authors.initials: I
authors.lastname: Elmaghraby
authors.affiliation: Botany and Microbiology Department, Faculty of Science, Helwan University, Ain-Helwan, Cairo, 11970, Egypt.
authors.forename: R M
authors.initials: RM
authors.lastname: Elbaz
authors.affiliation: Microbiology Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt.
authors.forename: E M
authors.initials: EM
authors.lastname: Marei
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D001483:Base Sequence; D005075:Biological Evolution; D036022:Capsid Proteins / Q000235:genetics; D002712:Chlorides / Q000494:pharmacology; D004279:DNA, Viral / Q000302:isolation & purification; D004534:Egypt; D005814:Genes, Viral; D016679:Genome, Viral / Q000235:genetics* / Q000502:physiology*; D023281:Genomics; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods; D058507:Host Specificity; D015636:Magnesium Chloride / Q000494:pharmacology; D016366:Open Reading Frames / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D012965:Sodium Chloride / Q000494:pharmacology; D012987:Soil; D012988:Soil Microbiology; D013302:Streptomyces / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics; D014771:Virion; D017967:Zinc Compounds / Q000494:pharmacology
chemical_list: D036022:Capsid Proteins; D002712:Chlorides; D004279:DNA, Viral; D012987:Soil; D014764:Viral Proteins; D017967:Zinc Compounds; D015636:Magnesium Chloride; D012965:Sodium Chloride; C016837:zinc chloride
keywords: Bacteriophage; Biological stability; Comparative genomics; NGS; Whole genome sequence