不同禽类传染性法氏囊病毒VP_2基因的克隆与序列比较分析

Cloning and sequence analysis of the VP_2 gene of IBDV isolated from different fowls

应用RT-PCR法对分离于不同禽类的IBDV HN 01株(鸡源)、W J株(乌鸡源)和YL 997株(鸭源)的VP2基因分别进行了克隆,对其与核苷酸序列及其编码的VP2蛋白氨基酸序列进行了分析,并对此3株IBDV与标准血清Ⅰ型STC株的VP2基因和VP2蛋白进行了同源性分析。结果表明,W J株、LY 997株、HN 01株与标准血清Ⅰ型STC株的核苷酸同源性分别为91.30%,92.50%和93.47%,氨基酸同源性分别为92.74%,91.90%和95.10%;HN 01株与W J株的核苷核和氨基酸的同源性分别为97.9%和98.4%,HN 01株与LY 997株的核苷酸和氨基酸的同源性分别为98.7%和99.05%,W J株与LY 997株的核苷酸和氨基酸同源性分别为99.1%和97.68%,3个毒株的VP2基因序列均完全具备超强毒株的主要特征,均为超强毒株,且与标准血清Ⅰ型STC株的核苷酸和氨基酸同源性均较低;3个野毒株之间虽具有较高的同源性,但相互之间也有一定的差异。

The VP2 gene of IBDV field strains HN01 （chicken）,WJ （dark-bone chicken） and LY997 （ducks） were amplified by RT PCR and cloned into PMD18-T vector to analyze sequence. The sequences of WJ,LY997 and HN01 isolates were compared with standard Ⅰ sterotype IBDV （STC）. The homology of the nucleotide were 91. 30%, 92. 50%, 93. 47%,and the homology of amino acids were only 92. 74%, 91.90%,95. 10% separately ; Between HN01 isolate and WJ isolate,the homology of the nucleotide and amino acids were 97.90% and 98.40% respectively;HN01 sequence was compared with LY997 isolate,the homology of the nucleotide and amino acids were only 98. 7% and 99.05% and the homologies of nucleotide and amino acids were only 99.1% and 97. 68% between WJ isolate and LY997 isolate. The VP2 gene sequences of the three isolates all possessed the characteristics of very-virulent IBDV （vvIBDV） ,the homologies of nucleotide and amino acids of the three isolates and standard Ⅰ stertype IBDV were very low. Although the homology of the three isolates were very high ,there are some differences among them.