The invention provides an application of deletion of genes cdtA, hctA, acbD, ccbF1 and / or
aroA in reduction of
pathogenicity of avibacterium paragallinarum. The
nucleotide sequences of the genes cdtA, hctA, acbD, ccbF1 and
aroA are shown as SEQ ID No.1-5. The invention further provides an application of the deletion of the genes cdtA, hctA, acbD, ccbF1 and
aroA in reduction of
pathogenicity of avibacterium paragallinarum. The invention also provides the Avibacterium paragallinarum Apg double
gene deletion strain A type GZ acb-aroA, and the preservation number of the Avibacterium paragallinarum Apg double
gene deletion strain A type GZ acb-aroA is CGMCC (China General Microbiological The invention further provides a chicken
infectious rhinitis live vaccine containing the GZ acb-aroA. According to the invention, a capsular
gene natural deletion strain is screened, and the aroA gene is deleted by adopting a natural
conversion method, so that the feasibility and high efficiency of the natural
conversion method are verified. The GZ acb-aroA strain disclosed by the invention has the advantages that the
pathogenicity of chicken is obviously reduced, the safety is good, an aluminum
hydroxide adjuvant is added to prepare a
vaccine product, and an ideal protection effect can be achieved after leg
intramuscular injection.