Abstract
To gain comprehensive genetic information of circulating avian coronavirus infectious bronchitis virus (IBV) isolates in China, analysis of the phylogenetic tree, entropy of the amino acid sequences, and the positive selection as well as computational recombinations of S1, M and N genes of 23 IBV isolates was conducted in the present study. The phylogenetic trees based on the S1, M and N genes exhibited considerably different topology and the CK/CH/LSC/99I-type isolates were the predominant IBVs based on the phylogenetic analysis of S1 gene. Results of entropy of amino acid sequences revealed that the S1 gene had the largest variation; the M gene had less variation than the N gene. Positive selections were detected in not only S1 but also M and N gene proteins. In addition, five S1 gene recombinants between vaccine strain 4/91 and CK/CH/LSC/99I-type field isolate were confirmed. In conclusion, multiple IBV genotypes co-circulated; genetic diversity and positive selections existed in S1, M and N genes; 4/91 vaccine recombinants emerged in China. Our results show that field IBVs in China are continuing to evolve and vaccine strains may have an important role in the appearance of new IBV strains via recombination. In addition, the present study indicates that IBV evolution is driven by both generations of genetic diversity and selection.
Highlights
Infectious bronchitis (IB) is an acute, highly infectious and contagious disease of domestic chickens worldwide caused by avian infectious bronchitis virus (IBV), a member of genus Gammacoronavirus, subfamily Coronavirinae, family Coronaviridae [1]
We previously reported the genotype diversity of Guangxi IBV isolates based on the hypervariable region I (HVR I) of S1 gene [15], but the available comprehensive genetic information of circulating IBV strains in this region was limited
In the present study we performed the analysis of the phylogenetic tree, of the entropy of the amino acid sequences, of positive selection as well as of computational recombination based on the sequencing results of the viral structural protein genes S1, M and N in order to provide molecular epidemiology information of IBV
Summary
Infectious bronchitis (IB) is an acute, highly infectious and contagious disease of domestic chickens worldwide caused by avian infectious bronchitis virus (IBV), a member of genus Gammacoronavirus, subfamily Coronavirinae, family Coronaviridae [1]. It is extremely critical to identify the prevalence of IBVs and genetic characteristics of circulating strains in a region or a country in order to develop effective vaccines for the control of the disease. We previously reported the genotype diversity of Guangxi IBV isolates based on the hypervariable region I (HVR I) of S1 gene [15], but the available comprehensive genetic information of circulating IBV strains in this region was limited. In the present study we performed the analysis of the phylogenetic tree, of the entropy of the amino acid sequences, of positive selection as well as of computational recombination based on the sequencing results of the viral structural protein genes S1, M and N in order to provide molecular epidemiology information of IBV and to lay a good foundation for the control of IB in the field
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
