猪圆环病毒2型广东分离株的基因序列分析

Sequence Analysis of Complete Genome of Porcine Circovirus Type 2 Isolates from Guangdong Province

【目的】本文研究了广东猪圆环病毒2型(PCV2)基因的遗传变异。【方法】采集来自不同猪场疑似PMWS的组织样品15份,用PK-15细胞增殖病毒,并进行间接免疫荧光试验鉴定,采用PCR方法扩增PCV2全基因组序列,分析其核苷酸和氨基酸序列的变异情况。【结果】GD-1和GD-2属于PCV2d亚型,其基因组由1767个核苷酸组成;GD-3,GD-4和GD-5属于PCV2a亚型,基因组由1768个核苷酸组成。5个分离株的核苷酸序列同源性为95.0%~99.9%;PCV2分离株ORF1的核苷酸和氨基酸序列高度保守,其同源性分别为96.8%~100%和99.4%~100%;GD-1和GD-2由702个核苷酸组成,编码233个氨基酸,GD-3、GD-4和GD-5由705个核苷酸组成编码234个氨基酸,5个分离株ORF2的核苷酸和氨基酸序列同源性分别为89.9%~99.9%和88.0%~100%。【结论】广东省确实存在PCV2,但可能存在由PCV2b到PCV2d的变异。因此,有必要进一步研究PCV2基因变异对其致病性与Cap蛋白抗原性的影响,为培育和筛选更为有效的疫苗株奠定基础。

【Objective】This paper aimed to investigate the genetic variation of porcine circovirus type 2(PCV2)in Guangdong province.【Method】15 tissue samples were collected from sick pigs clinically suspected post weaning multisystemic wasting syndrome(PMWS),PK-15 cell was used to propagate virus,the isolates were identified by indirect immunofluorescence assay(IFA),the complete genome sequences of the identified PCV2 strains were amplified by PCR,and the nucleotide and deduced amino acids sequences of the isolates were analyzed subsequently.【Result】The genome of PCV2 isolates GD-1and GD-2 were consisted of 1767 nucleotides belonged to PCV2d subtype;the genome of GD-3,GD-4 and GD-5 were consisted 1768 nucleotides belonged to PCV2d subtype.The nucleotide homology of the 5 isolates was 95.0%-99.9%;The nucleotide and amino acid sequences of ORF1 were highly conservative,and the homology of the 5 isolates came to 96.8%-100%and 99.4%-100%,respectively.ORF2 of GD-1 and GD-2 were consisted of 702 nucleotides coding for 233 amino acids,wheras GD-3,GD-4 and GD-5 were consisted of 705 nucleotides coding for 234 amino acids,and the nucleotide and amino acid homology of ORF2 among 5 isolates were 89.9%-99.9%and 88.0%-100%,respectively.【Conclusion】There is a PCV2 in Guangdong province,but there may be a variation from PCV2b to PCV2d.Therefore,it is necessary to further study the effect of PCV2 gene mutation on its pathogenicity and Cap protein antigenicity,which lay the foundation for the cultivation and screening of more effective vaccine strains.