Genomic Mapping and Molecular Immunity of Porcine Reproductive and Respiratory Syndrome Virus and Porcine Circovirus Type 2

Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are two of the most important virus that affect the swine industry nowadays. Epizootic and spread of PRRS and PCV2 have rised serious threat and significant economic impact on the swine industry worldwide. In modern large-scale pig farms, the PRRSV and PCV2 usually co-infect the pigs, and increasing outbreak is observed. In order to control PRRSV and PCV2 effectively and reduce the economy loss due to these infections, genomic mapping and molecular immunity of one PRRSV strain and three PCV2 strains predominantly prevalent in Gansu province were investigated.Genome of PRRSV Gansu strain was obtained by RT-PCR, sequenced and analyzed by using DNAstar software. The genomic mapping and phylogentic tree of PRRSV were constructed. The results indicated that the complete genome of PRRSV Gansu strain is 15427bp in length with eight open reading frames (ORFs). The 5’end of non-coding region is 190bp and shares 56.3% to 97.9% nucleotide sequence homology with the reference sequence of other PRRSV strains published in GenBank. The ORF1 is 11822bp in length and included ORF1a and ORF1b, of which, the ORF1a is 7512bp and shares 54.3% to 98.7% nucleotide sequence homology and 49% to 99.3% deduced amino acid homology with the reference sequence of other PRRSV strains published in GenBank. The ORF1b is 4374bp and shares 60.8% to 95.5% nucleotide sequence homology and 49% to 99.3% deduced amino acid homology with the reference sequence of other PRRSV strains published in GenBank. The structure protein gene is 3819bp in length and has six structural protein regions, of which,ORF2 shares 93.1% to 96.6% sequence homology and 91.1% to 95.7% deduced amino acid homology, ORF3 shares 90.7% to 96.5% sequence homology and 89.4% to 92.5% deduced amino acid homology, ORF4 shares 88.1% to 95.5% sequence homology and 83.3% to 96.6% deduced amino acid homology, ORF5 shares 87.9% to 95% sequence homology and 87.1% to 95% deduced amino acid homology…
Key words: Porcine reproductive and respiratory syndrome virus; Porcine circovirus type 2; Gene clone; Genomic mapping; Molecular immunity