河南大蒜韭葱黄条病毒的分子鉴定及其系统进化分析

Molecular identification and phylogenetic analysis of leek yellow stripe virus from garlic in Henan province

2019年本研究对河南大蒜病害进行调查时发现当地大蒜病毒病发生比较普遍,为明确病原种类,我们对田间样品进行采集(累计采集疑似病样38份)并利用葱蒜类病毒引物对其进行了RT-PCR检测。结果发现,在用韭葱黄条病毒(Leek yellow stripe virus,LYSV)引物检测时,有33份样品中检测到1条大小为304 bp的目的条带,为了进一步确定检测到的病毒为LYSV,本研究对其外壳蛋白基因(CP)序列进行了克隆,结果发现其序列全长864 bp,编码1个由289个氨基酸组成的相对分子质量约32300的蛋白质。CP基因序列构建的系统进化树结果分析显示,其与LYSV其他分离物共同聚类到1个大分支,表明该病毒属于LYSV的1个分离物;同时序列分析结果也显示LYSV分为2支,本研究检测到的LYSV河南分离物与中国其他分离物共同聚类到1个分支,其中与中国厦门等地分离物同源性最高,而与之前检测到的河南分离物同源性相对较低。这些结果表明本研究在河南大蒜中检测到的病毒是韭葱黄条病毒,虽然之前在河南也有该病毒侵染大蒜的报道,但本研究检测到的分离物与之前报道的分离物之间差异比较大,暗示河南大蒜上可能出现了新的LYSV类型或株系,生产上应当重视。

In 2019,an investigation on garlic disease were carried out in Henan province,and virus-infected garlic plants was found in many fields.To clarify the type of pathogen,field samples(38 suspected samples)were collected and detected by RT-PCR.The results showed that a target band about 304 bp was detected in 33 samples by using the primer for leek yellow stripe virus(LYSV).To further confirm the presence of LYSV,the sequence of coat protein(CP)gene was cloned.It was found that CP gene was 864 bp in length and encoded a protein with a relative molecular weight of 32300.The results of phylogenetic tree constructed by CP gene indicated that the isolates from Henan clustered with other isolates of LYSV,indicating that the virus from Henan was an isolate of LYSV.Meanwhile,LYSV was clustered into two branches.The isolates identified in this study and other isolates from China was clustered into one branch and shared the highest homology with the isolates from Xiamen,while the homology with the previousty reported isolates in Henan was relatively low.All these results showed that the virus detected from Henan garlic plant was an isolate of LYSV,and there was a big difference between the isolates,indicating that the virus might be a new strain or type of LYSV.