ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2015, Vol. 46 ›› Issue (5): 815-823.doi: 10.11843/j.issn.0366-6964.2015.05.018

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Isolation and Analysis of Structural Protein Genes Variation and Serotype of a Recombinant Strain of Chicken Infectious Bronchitis Virus

WU Cui-lan,HE Yi-ning,LI He-ming,SUN Xin-kuan,TAN Yu-cai,WEI Tian-chao,MO Mei-lan*,WEI Ping*   

  1. (College of Animal Science and Technology,Guangxi University,Nanning 530005,China)
  • Received:2014-09-10 Online:2015-05-23 Published:2015-05-23

Abstract:

In order to further understand the genetic variation of circulating infectious bronchitis virus(IBV),S1,EM and N genes of an IBV strain(GX-NN130048),which was isolated from chickens with immunoprophylaxis defeat in Guangxi,were amplified by reverse transcriptase polymerase chain reaction(RT-PCR),and then cloned,sequenced,and similarity comparison,phylogenetic tree,recombination and serotype analysis were conducted.The results showed that the gene sequence of cleavage site within S protein of GX-NN130048 was RRSRR.The nucleotide similarities of S1,EM and N genes with those of other reference strains were 60.8%-90.1%,81.0%-94.2%,86.1%-93.8% and 86.0%-93.3%,respectively.According to the phylogenetic tree analysis,it was clustered into 4/91-type based on S1 gene,while its EM and N genes belonged to LX4-type.Recombination event was detected in S1 gene,which was a recombinant between vaccine strain 4/91 and isolate GX-HC1006(LX4-type).The serotype analysis revealed that the serotype of GX-NN130048 was different from vaccine strains H120 and 4/91.The results indicated that isolate GX-NN130048 was a recombinant strain and variation existed both in structural genes and serotype.Our results also provide the evidence that the vaccine strain 4/91 has been increasingly involved in genetic variation of IBV epidemic strains,which may lead to the emergence of new serotype,and that may be one of the main causes of vaccine break in the field.Therefore,it is necessary to strengthen the monitoring of IBV field isolates and development of new vaccines.

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