Characterization of Porcine Reproductive and Respiratory Syndrome Virus Deletion Mutant

The genome of the isolate of porcine reproductive and respiratory syndrome virus (PRRSV) from China,designated HPBEDV,was sequenced and analyzed. The size of the genome of HPBEDV was 15 334 nucleotides (nt). Comparative analysis of HPBEDV with the genomic sequences of the domestic and other isolates (JXA1,HuN4,CH-1a,BJ-4,VR2332,and LV) revealed that HPBEDV shared 98.4,98.0,89.0,88.7,and 88.6% identity with the American strain JXA1,HuN4,CH-1a,BJ-4,and VR2332,respectively,but only 54.7% identity with the European reference strain Lelystad virus. The NSP2 gene had 2 850 nt and encoded 950 amino acids (aa),with two discontiguous deletions of 1 aa and 29 aa at positions 482 and 534-562,respectively,relative to VR-2332. Also,phylogenetic analysis with the published PRRSV genomic sequences indicated that the newly emerging isolate form a clade with the VR-2332 isolates. Therefore,HPBEDV was a novel strain with deletions in NSP2 gene.