Abstract: In order to enrich the ORF3 target protein information of porcine torque teno sus virus 1b (PTTSuV-1b), two parts of ORF3 fragments were amplified by PCR method from sera of the piglets association with post-weaning multisystem wasting syndrome in Fujian province. Then the target PCR products were cloned and sequenced. The results demonstrated that PTTSuV-1b ORF3 gene was 600 bp in length, coding an open reading frame (ORF) with 199 amino acids. The nucleotide sequence and amino acid sequence deduced from the gene were analyzed by the bioinformatics software. Compared with the PTTSuV-1b ORF3 genes download from GenBank, the sequenced gene shared the highest homogeneity with FJ/China/2010/TTV2/2 strain at 99.7%, with the SC strain at 94.0%, with the Spain PTTSuV-1b TTV2_G43 isolates at 97.3%. However, the PTTSuV-1b ORF3 genes shared with the torque teno sus virus K2 472142 stain isolated from Germany at 60.7%, with the Spain PTTSuV-1a PTTV1_1914 isolates at 46.8%. According to the results of the phylogenetic relationship constructed with Mega, PTTSuV-1b had two distinguish branches (branchⅠ and branch Ⅱ), the Fujian isolates were at the branchⅠ.

Key words: porcine torque teno sus virus 1b; ORF3 gene; sequence analysis