不同来源苹果茎沟病毒分离物部分序列分子特性研究

Study on the Molecular Characteristics of Partial Sequence from Different Sources Isolates of Apple stem Grooving Virus

【目的】明确为害新疆不同品种梨的苹果茎沟病毒(Apple Stem Grooving Virus,ASGV)侵染状况,并对获得的病毒基因序列进行分子鉴定。【方法】采用生物学和分子生物学方法对来源于新疆梨、砂梨及红梨上的ASGV进行检测,将获得基因序列进行比对分析。【结果】从10份新疆梨2、份砂梨及3份云南红梨样品上扩增到预期大小为500 bp的ASGV扩增产物。对扩增产物进行克隆和测序,序列分析的结果显示,15个ASGV分离物的CP基因核苷酸及其编码的氨基酸序列相似性分别为88.2%～100%和95.6%～100%。CP基因核苷酸序列构建系统发育树显示,来源于库尔勒香梨分离物KII-3、KII-5、KII-7和新梨7号的分离物XII-5、XII-6,与早期已报道的库尔勒香梨分离物KRL-1及砂梨分离物P-6-1-17亲缘关系较近,聚集成簇。此外,库尔勒香梨的分离物KII-10、KII-14及新梨7号的分离物XII-10与云南红梨上2个分离物YN-2和YN-4聚集成簇,遗传距离较近。【结论】CP基因核苷酸序列系统发育树显示,来源于新疆不同品种梨的8个ASGV分离物及红梨上3个ASGV分离物位于两个不同的组群,存在复杂遗传变异现象。

[Objective] In order to know the Apple Stem Grooving Virus infection status of pears in Xinjiang,and to identify gene sequences from obtaining virus.[Method]ASGV in pears from Xinjiang,Pyrus pyrifolia and Red pear were detected by biological and molecular methods and the gene sequences obtained were comparatively analyzed.[Result]The ASGV products with a expected size about 500 bp were amplified from 10 pear samples in Xinjiang,2 samples of Pyrus pyrifolia and 3 Red pear samples from Yunnan province by RT-PCR.All these amplified products were cloned and sequenced.Comparison of these sequences showed that the CP gene from these isolates shared similarities ranging 88.2-100%（nt） and 95.6-100%（aa）,respectively.The phylogenetic tree was constructed based on amino acid of CP gene of detected ASGV isolates and reference isolates.Results showed that isolates KII-3,KII-5,KII-7 of Korla pear,XII-5 and XII-6 of New pear no.7 had lower genetic distances and clustered into a branch with a isolate KRL-1 early reported from Korla pear,and another isolate P-6-1-17 from Pyrus pyrifolia.In addition,isolates KII-10,KII-14 of Korla pear,XII-10 of New pear no.7 was closer to YN-2,YN-4 of Red pear and they were clustered into another branch.[Conclusion]Phylogenetic tree of cp gene nucleotide sequences displayed 8 ASGV isolates from Xinjiang and 3 isolates from Red pear have complex genetic variation phenomenon and in two different branches separately.