title: Comparative analysis of multiple inducible phages from Mannheimia haemolytica.
abstract: BACKGROUND
  Mannheimia haemolytica is a commensal bacterium that resides in the upper respiratory tract of cattle that can play a role in bovine respiratory disease. Prophages are common in the M. haemolytica genome and contribute significantly to host diversity. The objective of this research was to undertake comparative genomic analysis of phages induced from strains of M. haemolytica serotype A1 (535A and 2256A), A2 (587A and 1127A) and A6 (1152A and 3927A).
  
  
  RESULTS
  Overall, four P2-like (535AP1, 587AP1, 1127AP1 and 2256AP1; genomes: 34.9-35.7 kb; G+C content: 41.5-42.1 %; genes: 51-53 coding sequences, CDSs), four λ-like (535AP2, 587AP2, 1152AP2 and 3927AP1; genomes: 48.6-52.1 kb; 41.1-41.4 % mol G+C; genes: 77-83 CDSs and 2 tRNAs) and one Mu-like (3927AP2; genome: 33.8 kb; 43.1 % mol G+C; encoding 50 CDSs) phages were identified. All P2-like phages are collinear with the temperate phage φMhaA1-PHL101 with 535AP1, 2256AP1 and 1152AP1 being most closely related, followed by 587AP1 and 1127AP1. Lambdoid phages are not collinear with any other known λ-type phages, with 587AP2 being distinct from 535AP2, 3927AP1 and 1152AP2. All λ-like phages contain genes encoding a toxin-antitoxin (TA) system and cell-associated haemolysin XhlA. The Mu-like phage induced from 3927A is closely related to the phage remnant φMhaMu2 from M. haemolytica PHL21, with similar Mu-like phages existing in the genomes of M. haemolytica 535A and 587A.
  
  
  CONCLUSIONS
  This is among the first reports of both λ- and Mu-type phages being induced from M. haemolytica. Compared to phages induced from commensal strains of M. haemolytica serotype A2, those induced from the more virulent A1 and A6 serotypes are more closely related. Moreover, when P2-, λ- and Mu-like phages co-existed in the M. haemolytica genome, only P2- and λ-like phages were detected upon induction, suggesting that Mu-type phages may be more resistant to induction. Toxin-antitoxin gene cassettes in λ-like phages may contribute to their genomic persistence or the establishment of persister subpopulations of M. haemolytica. Further work is required to determine if the cell-associated haemolysin XhlA encoded by λ-like phages contributes to the pathogenicity and ecological fitness of M. haemolytica.
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. dongyan.niu@gov.ab.ca.|Alberta Agriculture and Rural Development, Agriculture Centre, Lethbridge, AB, T1J 4V6, Canada. dongyan.niu@gov.ab.ca.
authors: Yan D
authors: YD
authors: Niu
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. shaun.cook@agr.gc.ca.
authors: Shaun R
authors: SR
authors: Cook
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. jiaying.wang@agr.gc.ca.|College of Veterinary Medicine, South China Agricultural University, Guangdong, 510642, People's Republic of China. jiaying.wang@agr.gc.ca.
authors: Jiaying
authors: J
authors: Wang
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. cassidy.klima@agr.gc.ca.
authors: Cassidy L
authors: CL
authors: Klima
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. hsuyuhung@yahoo.com.|Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada. hsuyuhung@yahoo.com.
authors: Yu-hung
authors: YH
authors: Hsu
authors: Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, ON, N1G 3W4, Canada. kropinsk@queensu.ca.|Department of Molecular Biology, Cellular Biology and Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada. kropinsk@queensu.ca.
authors: Andrew M
authors: AM
authors: Kropinski
authors: Centre for Research in Biosciences, Department of Applied Sciences, University of the West of England, Coldharbour Lane, Bristol, BS16 1QY, UK. Dann2.Turner@uwe.ac.uk.
authors: Dann
authors: D
authors: Turner
authors: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, T1J 4B1, Canada. tim.mcallister@agr.gc.ca.
authors: Tim A
authors: TA
authors: McAllister
mesh_terms: D001482:Base Composition; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D016978:Mannheimia haemolytica / Q000821:virology*; D008969:Molecular Sequence Data; D039002:Prophages / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D026801:Synteny; D014775:Virus Activation
chemical_list: D004279:DNA, Viral