马铃薯Y病毒在种薯中检出率及其株系鉴定

 马铃薯是我国重要粮食和经济作物。马铃薯Y病毒(potato virus Y,PVY)是危害马铃薯生产的重要病害。种植脱毒种薯是防治PVY最有效的途径。马铃薯种薯携带PVY问题严重,但种薯中PVY株系还不清楚。本研究利用PVY特异性抗体检测了7个马铃薯品种362个种薯,发现不同品种种薯带毒率差异较大,最高达12%。通过RT-PCR方法扩增获得了7个PVY分离物编码区全序列。重组分析发现7个分离物基因组均为重组型,根据重组位点的差异可以分为PVY^NTN-NW(SYR-II型)、Rec-1、Rec-2和Rec-3等4种重组类型,后3种为新重组类型。系统进化分析发现,分离物HQH18G3-10与PVY^NTN-NW(SYR-II型)处于同一个大的分支,但与中国PVY大田分离物聚集在一起形成一个相对独立的组,命名为PVY^NTN-NW(CN型);其余6个分离物与数据库中的中国分离物聚集在PVY^N-Wi组。这暗示PVY中国分离物具有相对独立的进化过程,PVY马铃薯大田分离物和种薯分离物进化上相近。所有分离物均能在珊西烟上引起典型叶脉坏死症状,HQH18G3-10引起的坏死症状最为严重。本研究首次报道了我国种薯内PVY发生情况,对分析病毒发生发展规律和防控具有借鉴作用。

Incidence of potato virus Y and identification of its strain groups in seed potatoes

Potato is one of the most important food and economical crop in China.Potato virus Y (PVY) is the prevalent virus infecting potato.Currently,growing virus-free seed potato is the best strategy to control PVY.Previous studies have shown that seed potatoes are frequently contaminated with PVY,but the strains of PVY in seed potatoes remain unidentified.Here,we tested 362 seed potatoes from seven cultivars using Plate Trapped Antigen-Enzyme Linked Immunosorbent Assay (PTA-ELISA) with PVY specific antibody.It showed that the incidence of PVY was up to 12.0% and varied in different seed potato cultivars.Seven PVY nearly complete genome were obtained by RT-PCR.Sequence analysis showed that all these isolates were recombinants and could be divided into four patterns,namely NTN-NW SYR II,Rec-1,Rec-2,and Rec-3,respectively,based on recombination breakpoints.Isolate HQH18G3-10 and other Chinese potato isolates formed a separate group,named PVY^NTN-NW CN,which was close to PVY^NTN-NW SYR II group.The rest of isolates obtained in this study together with other Chinese isolates were clustered to PVY^N-Wi group.These results suggested that PVY Chinese isolates have a different evolutionary history.PVY isolates from seed potatoes were close to that from the potato fields.All the seven PVY isolates could cause veinal necrosis in Nicotiana tabacum cv.Xanthi plants and the isolate HQH18G3-10 caused the most severe necrosis symptoms.This is the first report of identification PVY strains infecting seed potatoes in China.The findings of this study will be useful to understand the epidemics of PVY and facilitate its management.