EM observation and RT-PCR of the S1 gene of five Chinese isolate of avian infectious bronchitis virus

According to the sequence of the genome of the Beaudette strain of IBV, three primers (you1+、you2- and youM+) were designed and synthesized. The primers you1+ and you2-locate respectively in the 5^-most and the 3^-most of the S1 gene and approximately cover 1 610 bp; the primer youM+ lies in the middle of the S1 gene. RT-PCR was used to amplify the S1 gene fragment of the five Chinese isolates of IBV (HN2, HN4, JX1, SC2 and SC1) using the three primers. Two special PCR fragments (1 610 bp and 530 bp) were observed respectively. The virus were observed with transmission electron microscope (EM), and a lot of viral particles were seen.