野茼蒿黄脉病毒的田间寄主范围及其基因多样性特征

Natural hosts and genetic diversity of Crassocephalum yellow vein virus

为明确野茼蒿黄脉病毒(Crassocephalum yellow vein virus,CraYVV)的田间寄主范围及其群体基因结构特征,分别采用克隆和测序技术对采自云南省西双版纳傣族州、红河哈尼族彝族自治州的7种杂草和2种作物进行CraYVV的分离和鉴定,并通过生物信息学软件对分离到的CraYVV进行基因组结构、重组及基因遗传结构分析。结果显示,在赛葵、龙葵、臭牡丹、水茄、豨莶、野茼蒿和一点红7种杂草以及茄子和草莓2种作物中均分离到CraYVV,共获得20条CraYVV全长序列;CraYVV所有分离物分属2个株系,将其命名为YJ株系和JH株系;JH株系具有地理隔离特征,与YJ株系存在一定的遗传距离;重组分析显示,CraYVV是由烟草曲茎病毒(tobacco curly shoot virus,TbCSV)和云南烟草曲叶病毒(tobacco leaf curl Yunnan virus,TbLCYnV)重组产生;遗传结构分析显示,CraYVV中C1基因变异最显著,其次是C4基因和基因间隔区。表明CraYVV能侵染5科9种杂草和作物,具有较广的寄主范围,且菜豆金色花叶病毒属病毒能够侵染草莓、CraYVV能够侵染茄子,显示来源于杂草的菜豆金色花叶病毒属病毒在自然条件下能够侵染作物。

To investigate the natural host range and genetic diversity of Crassocephalum yellow vein virus(CraYVV), leaf samples were collected from seven weeds and two crop species in Xishuangbanna Dai and Honghe Hani and Yi Autonomous Prefecture in Yunnan Province, China. CraYVV isolates were identified with cloning, sequencing, and characterized by genetic diversity analyses. The results showed that all these plants were infected by CraYVV and 20 full-length sequences of CraYVV were obtained from these samples. These CraYVV isolates could be classified into two strains, the YJ strain and the JH strain. Phylogenetic analysis supported that the JH strain displayed geographical division and was clearly different from the YJ strain. Recombination analysis showed that CraYVV was likely originated by recombination between tobacco curly shoot virus(TbCSV) and tobacco leaf curl Yunnan virus(TbLCYnV). Additionally, population structure analysis revealed that the greatest variation was found in the CraYVV C1 gene, followed by the C4 gene and the intergenic region(IR). Taken together,these results established that CraYVV has a wide host range including nine plant species belonging to five families. The data represent the first report of begomovirus infecting strawberry and eggplant, and also provide evidence that weeds serve as reservoirs for crop-infecting begomovirus diseases.