Molecular analysis of the S1 gene of vaccine strains of infectious bronchitis virus using reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism

Infectious bronchitis virus (IBV) is an acute and contagious viral disease of poultry that affects different systems, including the respiratory tract in particular. IBV causes major economic losses in the poultry industry globally. Due to antigenic variation of the causative agent, control of the disease is difficult. To control the disease, many vaccines that belong to different serotypes are being used in many countries, including Iran. In the present study, the S1 genes of six different IBV vaccines were analyzed. The S1 genes of IBV vaccine strains were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR)and the resultant PCR products were purified. Purified PCR products were digested separately with the restriction endonuclease, AluI. The generated restriction endonuclease fragment length polymorphism (RFLP) patterns of the S1 gene of IBV vaccine strains were compared. The results showed that the construction of a library of RFLP patterns of the S1 gene of vaccine strains in use is beneficial. The library has the potential for use as a quick and inexpensive method for determining the genotype of future outbreaks of IBV and also assesses the degree of their similarity to the strains for which vaccines exist.