title: Evaluation of a novel strain of infectious bronchitis virus emerged as a result of spike gene recombination between two highly diverged parent strains.
abstract: The emergence of new variant strains of the poultry pathogen infectious bronchitis virus (IBV) is continually reported worldwide, owing to the labile nature of the large single-stranded RNA IBV genome. High resolution melt curve analysis previously detected a variant strain, N1/08, and the present study confirmed that this strain had emerged as a result of recombination between Australian subgroup 2 and 3 strains in the spike gene region, in a similar manner reported for turkey coronaviruses. The S1 gene for N1/08 had highest nucleotide similarity with subgroup 2 strains, which is interesting considering subgroup 2 strains have not been detected since the early 1990s. SimPlot analysis of the 7.2-kb 3' end of the N1/08 genome with the same region for other Australian reference strains identified the sites of recombination as immediately upstream and downstream of the S1 gene. A pathogenicity study in 2-week-old chickens found that N1/08 had similar pathogenicity for chicken respiratory tissues to that reported for subgroup 2 strains rather than subgroup 3 strains. The results of this study demonstrate that recombination is a mechanism utilized for the emergence of new strains of IBV, with the ability to alter strain pathogenicity in a single generation.
authors.affiliation: a Faculty of Veterinary Science, Veterinary Clinical Centre , The University of Melbourne , Parkville , VIC , Australia.
authors.forename: Kylie A
authors.initials: KA
authors.lastname: Hewson
authors.forename: Amir H
authors.initials: AH
authors.lastname: Noormohammadi
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Devlin
authors.forename: Glenn F
authors.initials: GF
authors.lastname: Browning
authors.forename: Bridie K
authors.initials: BK
authors.lastname: Schultz
authors.forename: Jagoda
authors.initials: J
authors.lastname: Ignjatovic
mesh_terms: D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000821:virology*; D018352:Coronavirus Infections / Q000662:veterinary* / Q000821:virology; D001351:Infectious bronchitis virus / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011201:Poultry Diseases / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA / Q000662:veterinary; D064370:Spike Glycoprotein, Coronavirus / Q000235:genetics*; D014132:Trachea / Q000821:virology; D056189:Viral Tropism; D014774:Virulence
chemical_list: D012367:RNA, Viral; D064370:Spike Glycoprotein, Coronavirus