Cloning And Sequence Analysis Of 3 Porcine Circovirus Type 2 Strains

Porcine circovirus type 2 (PCV2), confirmed in recent years, was the primary causative agent of a swine disease, which is associated with multisystemic wasting syndrome (PMWS), reproductive failure/sow abortion and mortality syndrome (SAMS), porcine respiratory disease syndrome (PRDS), porcine dermatitis and nephropathy syndrome (PDNS), congenital tremor type A2 (CT), intersticial pneumonia (IP), proliferative and necrotizing pneumonia(PNP). Beacause of this, these diseases are collectively called PCV2 infection or PCV2 disease (PCVD), or porcinecircovirus associated disease (PCVAD). This disease was first confirmed in 1991. Since then, it has rapidly become a pandemic virus and brought great losses in pig production worldwide, seriously threatening the development of pig industry. To investigate the epidemiological situation and gentic variation of PCV2 in Sichuan Province, the whole genome of the 3 PCV2 isolates(PCV22012S1、KPCV22012S2and PCV22013S1) was amplified by using the primers designed based on the genomic deposited in GenBank. The PCR products were purified and cloned into pMD19-T vector and sequenced with an automated sequencer. After that, the 3 genomes were analyzed by using DNAstar software. The results show that the genomes of these3 PCV2 isolates are all 1767 bp in the lengthand the homology of nucleotide sequenceare99.5%-99.9%; the homology at nucleotide level ofORF1 and ORF2 between these3 PCV2 isolatesare99.8%-99.9% and 99.4%-100%, respectively, while the homologous at amino acid level of ORF1 and ORF2 between these 3 PCV2 isolates are 99.4%-99.9% and 99.6%, respectively. Phylogenetic analyses based on the genome of PCV2 strains, including 45 reference sequences deposited in GenBank, indicate that the 3 PCV2 strains isolated in this study together with GL08 (accession no. FJ644929), HB (accession no. AY291317) from China and INDON07-P09-07-07Lg1 (accession no. EU302140) from Singapore are grouped in one cluster, which belongs to a new gene sub-genotype PCV2c.In this study,3 PCV2 strains form Sichuan Province were isolated, sequenced and analyzed, and this work will provide crucial dataand support for PCV2 control and prevention.