田间采集辽宁地区烟叶脉坏死病标样所得分离物，在测定的１２个科３５种植物中只侵染茄科的一些烟草品种及洋酸浆（ｐｈｙｓａｌｉｓｆｌｏｒｉｄａｎａ），可由桃蚜（Ｍｙｚｕｓｐｅｒｓｉｃａｅ）传播。病叶汁液稀释限点（ＤＥＰ）为１０￣（－２）－v１０￣（－３）；失毒温度（ＴＩＰ）为５５一６０℃；体外保毒期（Ｌ）为４８－７２小时。病毒粒体形态呈线条状７２０×１２ｎｍ，病叶脉坏死部细胞质中含风轮状内含体。病毒提取物的紫外最大吸收为２６５ｎｍ，最小吸收为２４５ｎｍ，Ａ＿（２８０）／Ａ＿（２６０）为０．８２。该病毒分离物与ＰＶＹ￣０抗血清呈阳性反应。以病毒ＲＮＡ为模板，按国外报道的ＰＶＹ￣Ｎ序列合成引物经逆转录合成ｃＤＮＡ。用ＰＣＲ扩增出约０．８０ｋｂ的ＣＰ基因片段，将这一片段插入载体ｐＧＥＭ７Ｚ－ｆ（＋）中转化Ｅ．ｃｏｌｉＤＨ５ａ菌株得到了ＣＰ基因的克隆。ｃＤＮＡ序列分析表明，和国外报道的ＰＶＹ￣Ｎ序列同源性极高，初步表明引起辽宁地区烟叶脉坏死病的毒原为ＰＶＹ￣Ｎ。

Identification , cDNA cloning and sequencing of a virus causing tobacco veinal necrosis were carried out during 1 990一1993. The obvious symptom of the infected tobacco was veinal necrosis. Aphid(Myzus persicae)was demonstrated as transmitting vector. The virus only in-fected 8 species of tobacco and Physalis floridana form solanaceae,out of 35 species from 13 families tested.It's thermal inactivation point was 50一55℃,dilution end point was 1 0(-3)-10(-4),and longevity in vitro was 48-72 hours. The virus particles were flexous rods with Sizeof 720×12nm. Scroll,pinwhell and boundle inclusion were found in cytoplasm of leaf tissues of infected tobacco. The virus could react with the antiserum of PVY￣0 by immunoelec-trophoresis test.Purified virus had A_(280)/A_(260)ratio of 0. 82. Using a pair of primers specific to PVY￣N,reverse transcription and PCR were performed.A specific fragment of 0. 80kb corre-sponding in size to the PVY￣N coat protein gene was amplified. T he products of PCR were cloned in plasmid