马铃薯Y病毒N-Wi株系广西分离物的鉴定

 马铃薯Y病毒 (potato virus Y,PVY) 是一种重要的农作物病毒,可造成产量损失和产品质量下降。其宿主范围广泛,包括马铃薯、烟草、番茄和辣椒等经济作物。在广西从叶片表现斑驳褪绿症状的马铃薯上分离到一株PVY分离物DX,其基因组包含一个大的开放阅读框 (open reading frame,ORF),由9 186 nt组成,编码3 061个氨基酸。系统发育进化分析显示,分离物DX与PVY^N-Wi株系分离物IUNG-12、SGS-AG、MAF-VOY聚类成一个分支。重组分析表明分离物DX基因组在496 nt和2 388 nt存在重组位点,分别位于P1和HC-Pro/P3结合区,是分离物Oz和N605的重组体。通过机械摩擦接种,分离物DX可侵染茄科9种作物,引起本生烟叶片花叶、皱缩和泡状突起等症状;引起普通烟草和番茄的轻微花叶症状;引起马铃薯叶片花叶症状,接种辣椒没有发病。序列比对分析显示,分离物DX缺乏引起烟草叶脉坏死相关的氨基酸位点N₂₀₅、K₄₀₀和E₄₁₉。本研究比较了分离物DX对茄科共12种作物的侵染能力和病害症状差异,结果表明分离物DX可用于探索PVY在不同寄主中的致病机理。

Identification of a PVYN-Wi isolate infecting potato in Guangxi,China

Potato virus Y is a widespread pathogen of several economically important crops including potato, tobacco, tomato and pepper. It has a wide host range and ability to cause significant quantitative and qualitative crop losses. In this study, a PVY isolate (named DX) was isolated from potato with leaf mosaic symptoms from Guangxi province. The virus genome consists of one large open reading frame which is 9 186 nt in length and encodes 3 061 amino acids. Phylogenetic analysis showed that isolate DX was clustered with isolates IUNG-12, SGS-AG and MAF-VOY and formed a separate branch, named N-Wi group. Recombination analysis showed that isolate DX had two recombination sites at 496 nt and 2 388 nt, which were located in P1 and HC-Pro/P3 region, respectively, and was a recombinant of isolate Oz and N605. By mechanical inoculation, the isolate DX could infect 9 crops of solanaceae. Isolate DX induced symptoms of mosaic, shrinkage and vesicular protuberant in Nicotiana benthamiana, mild mosaic in Nicotiana tabacum and tomato, and mosaic in potato. Whereas, isolate DX was unable to infect peppers. Sequence alignment analysis showed that isolate DX does not contain amino acids N₂₀₅, K₄₀₀ and E₄₁₉, which is related to tobacco leaf vein necrosis. In this study, the differences of the infectivity and disease symptoms of the isolate DX to 12 solanaceae crops were compared, indicating that the isolate DX could be used to explore the pathogenic mechanism of PVY in different hosts.