Bioinformatic analysis of gene 5b from different strains of infectious bronchitis virus

Infectious bronchitis virus (IBV) is a pathogen causes acute and highly contagious disease infectious bronchitis (IB) in domestic chickens. The virus belongs to group III of genus Coronavirus in the family of Coronaviridae. It has an unsegmented, positive sense, single-stranded RNA (ssRNA) genome of approximately 27.6 kb in length and contains at least 10 open reading frames (ORFs) included: 5 -1a-1b-S (S1, S2)-3a-3b-3c (E)-M-5a-5b-N-Poly (A)-3. Gene 5, encoding two accessory proteins 5a and 5b, has been explained as an important factor in the pathogenesis ofthe virus. In this study, the nucleotide sequences of OpenReadingFrame (ORF) 5b of gene 5 of different IBV reference strainswere obtained from GeneBank and molecular properties of the strains were analyzed usingbioinformatics software programs, Bioedite andMEGA7. Based on 5b nucleotide analysis, the rate of similarity among different strains of IBV was 86%-100%. Some strains from distinct geographical regions also had 100% similarity. The lowest similarity was observed between Australian strains with other IBVs (86%-95%). Based on the results of the phylogenetic tree of gene 5b, Australian strains grouped together in a distinct cluster while other regions IBVs were classified differently regardless to their originated regions. The high rate of similarity between different strains from distinct geographicalregions could confirm the important role of gene 5b in virus vital functions.

کلیدواژه ها:

Infectious bronchitis virus ، Gene 5b ، Phylogenetic tree ، Bioinformatics ، Open reading frame