申莉莉 宋丽云 龚明月 何青云 宋青松 王宝剑 刘文涛 李斌 王玉洁 蔺忠龙

摘 要：对引起花叶狭长及疱斑畸形重症的烟草黄瓜花叶病毒，采用生物学接种、CP基因扩增测序、电镜观察、免疫印迹、荧光定量等方法，研究病毒分离物的株系、粒体形态、致病力、稀释限点、传导路径以及在抗感烟草上的症状。结果显示，分离物外壳蛋白基因长度为657 bp，其核苷酸序列与亚组Ⅱ的代表Q株系同源性为69.83%，与亚组Ⅰ的代表Fny株系同源性为93.00%，介于ⅠA与ⅠB株系之间。病毒粒体球形，直径28～30 nm，对烟草致病力强。病汁液稀释限点为10-5，质量浓度40倍稀释接种后病毒由接种叶移动到主茎后，先向下至根、向上至心叶，再扩散布满全株，最后集中在上部叶。亮黄和G28对其表现高感，病叶狭窄、黄化斑驳、变薄革质化及疱斑畸形;Ti245和铁耙子表现中抗，病叶轻微脉明斑驳。

关键词：烟草;黄瓜花叶病毒;亚组Ⅰ;生物学特性

Abstract： Cucumber mosaic virus （CMV） showing heavy narrow mosaic and enation deformity on tobacco leaf was isolated. The strain， viral morphology， pathogenicity， dilution limit concentration， transmission route and symptoms on resistant and susceptible tobacco were studied via biological inoculation， CP gene sequencing， electron microscopy， western blot and qRT-PCR. The results showed that the 657 bp coat protein gene shared 69.83% homology to CMV group Ⅱof Q strain， 93.00% identity to CMV groupⅠof Fny strain， which were between ⅠA andⅠB strains. The virus particles were spherical， about 28-30 nm in diameter. It showed strong pathogenicity to tobacco. The dilution limit concentration of disease juice was 10-5 in vitro. After inoculation with 40 times dilution on tobacco， CMV systemically spread from inoculated leaf to stem， first down to root and up to heart leaf， then to whole plant， finally continued to upper new leaves. Bright yellow and G28 were susceptible， showing heavy narrow and yellow mosaic， leathery and distorted leaves. Ti245 and Tiepazi were moderate resistance， showing vein clearing and mild mosaic.

Keywords： tobacco; cucumber mosaic virus; subgroupⅠ; biological characteristics

黃瓜花叶病毒（cucumber mosaic virus，CMV）是雀麦花叶病科（Bromoviridae）黄瓜花叶病毒属（Cucumovirus）的代表种，是由RNA1、RNA2、RNA3组成的三分体正义单链RNA病毒。CMV严重危害我国烟叶生产，烟草苗期和成株期均可感染，以大田成株期发病较多，且CMV往往与其他病毒混合发生严重，烟草产量损失巨大[1-2]。

CMV不同株系或分离物其寄主范围不同，侵染同一寄主表现的症状存在一定差异。根据外壳蛋白（coat protein，CP）同源性可将其分为亚组Ⅰ和亚组Ⅱ[3]，根据RNA3的5'非编码区将亚组Ⅰ分为ⅠA和ⅠB[4-6]。亚组Ⅱ接种烟草引起温和的系统斑驳和接种叶上出现坏死斑纹，亚组Ⅰ导致严重的系统花叶畸形，但不引起坏死斑纹[7]。……