致鸭短喙与侏儒综合征的新型鹅细小病毒不同传代毒株基因组分析

Genomic Analysis of Different-passage Strains of the Novel Goose Parvovirus Causing Short Beak and Dwarfism Syndrome in Ducks

由新型鹅细小病毒(Novel goose parvovirus,N-GPV)引起的鸭短喙与侏儒综合征(Short beak and dwarfism syndrome,SBDS)给我国养鸭业带来了不可估量的经济损失,严重阻碍了我国养鸭业的发展。而目前N-GPV的毒力关键基因位点尚不清楚。本研究将N-GPV(SD株)在SPF鸭胚上进行多次传代,对SD株F10、F20、F30、F40和F50进行全基因组测序,并选择F50进行致病性试验,结果表明,F50感染组与对照组相比体重与喙长有明显差异,但F50感染组无典型临床症状,表明SD-F50的致病性明显降低;F50与F5序列分析显示,5’和3’的反向重复末端(ITR)中均有4个碱基突变和2个碱基插入,且突变位置相对应;在非结构蛋白Rep中有1个氨基酸位点突变,结构蛋白VP中共有2个氨基酸位点突变。综上所述,N-GPV SD株经过鸭胚连续传代后出现了毒力下降,并且病毒基因组序列也出现了规律性变化,这些突变位点可能是影响N-GPV毒力的关键位点,为N-GPV毒力关键位点的研究提供参考依据。

Short beak and dwarfism syndrome(SBDS) in ducks caused by the novel goose parvovirus(N-GPV)has brought inestimable economic losses to the duck industry and seriously hindered the development of duck industry in China. However,the key gene locus causing N-GPV virulence is not known. In the present study,N-GPV(SD strain)was passaged serially on specific pathogen-free duck embryos 50 times. The whole genome of F10,F20,F30,F40 and F50 of the SD strain were sequenced. F50 was selected for a pathogenesis study in animals. We discovered significant differences in bodyweight and beak length between the F50-infected group and control group. However,the F50-infected group did not show typical clinical symptoms,indicating that the pathogenicity of SD-F50 was decreased significantly. Sequencing of F50 and F5 showed four base mutations and two base insertions in the 5’ and 3’ inverted repeat terminal,one amino-acid mutation in the nonstructural protein Rep,and two amino-acid mutations in the structural protein VP. In summary,the virulence of the SD strain of the N-GPV decreased after serial passage of duck embryos,and the genomic sequence of the virus changed regularly. These mutation sites may be the key sites affecting the virulence of the N-GPV. Our study provides a reference for investigation of the key sites causing N-GPV virulence.