Isolation and molecular characterization of infectious bronchitis virus, isolate Shiraz3. IBV, by RT-PCRand restriction enzyme analysis

Infectious bronchitis virus (IBV) strain 4/91, prototype of the 793/B serogroup, was recently reported from Khouzestan province, Iran. Here we isolated and molecularly characterized a virus (Shiraz3. IBV) from broilers in Fars province. Following virus propagation in embryonated chicken eggs, we extracted total RNA containing the viral RNA from allantoic fluid. cDNA of the entire S1 and nucleocapsid (N) genes were generated with AMV-reverse transcriptase and genomic specific primers. The cDNA was subsequently amplified in a polymerase chain reaction (PCR). Digestion of the PCR products representing the entire S1 gene generated restriction fragments identical to those expected from strain 4/91 and differed from the control vaccine strain of H120. The N RT-PCR products representing the entire N genes of strains Shiraz3. IBV and H120 did not show any visible difference in size. The results presented here demonstrated that isolate Shiraz3. IBV is genetically closely related to strain 4/91 of IBV and can be differentiated from the IBV vaccine strain in Iran.