为明确我国马铃薯 Y 病毒(Potato virus Y, PVY)株系组成及其在不同寄主上的分布特征, 文章对31条PVY中国分离物的基因组编码区进行了系统发育及重组分析。系统发育分析结果显示, 最大似然法(maximum likelihood, ML)和邻接法(neighbor-joining, NJ)重建的系统发育拓扑结构基本一致, GF_YL20、FZ10、DF、SD1、1116和9703-3等6个分离物均未与已知株系相聚, 其他株系来源相同的分离物以较高的自展值相聚成簇, 显示出较强的株系特异性。重组分析显示, 31个PVY分离物中, 共有28个PVY分离物均检测到具有显著的重组信号, 这些分离物主要包括PVYN-Wi、PVYNTN和PVYNTN-NW三种株系。进一步分析显示, 分离物1104、DF、SD1、1116和9703-3为未报道过的PVY新重组分离物。株系统计结果显示PVY重组株系已上升为优势株系, 生产上需要密切注意这些株系, 尤其新重组分离物的发展动态。以上结果表明, 综合应用PVY全基因组序列的系统发育和重组分析, 可以实现PVY株系的准确鉴定。

To investigate the composition and distribution of Potato virus Y (PVY) strains across different hosts in China, phylogenetic and recombination analyses were studied using 31 complete coding sequences in PVY isolates. Phylogenetic analysis revealed that the NJ and ML bootstrap trees had broadly similar topologies, in which 6 isolates of GF_YL20, FZ10, DF, SD1, 1116 and 9703-3 are divergent from all known PVY strains and the remaining isolates from the same strain tended to group together with high bootstrap supports, showing a distinct strain feature among PVY isolates. Significant recombination signals were identified in 28 out of the 31 PVY isolates and the majority of them classified to PVYN-Wi, PVYNTN and PVYNTN-NW. Further analysis showed that 5 isolates of 1104, DF, SD1, 1116 and 9703-3 are novel N×O recombinants. Results from the composition and distribution of PVY strains indicated that recombinant strains were dominant in the PYV isolates in China. Thus, it is important to monitor the development of these recombinants in practice. The above results showed that all PVY isolates could be distinguished accurately using phylogenetic combined with recombination analyses.