烟草黄瓜花叶病毒亚组Ⅰ分离物生物学特性

Biological Characteristics of Cucumber Mosaic VirusSubgroupⅠfrom Tobacco

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。

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 groupⅡof Q strain,93.00%identity to CMV groupⅠof Fny strain,which were betweenⅠA 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.