Sabanadzovic S, Ingram D M, Lawrence A M
Department of Entomology and Plant Pathology, Mississippi State University, Mississippi State 39762.
Raymond, MS 39154.
Plant Dis. 2010 Jan;94(1):126. doi: 10.1094/PDIS-94-1-0126B.
Eupatorium purpureum L. (joe-pye weed, sweet joe-pye weed, and sweetscented joe-pye weed) is a wildflower perennial plant native to the eastern United States. In May 2006, virus-like symptoms including systemic chlorosis, mottling, and downward rolling of leaf blades were observed in a joe-pye weed plant located on the Mississippi State University campus. Young symptomatic leaves were ground in 0.1 M phosphate buffer, pH 7.2, and the slurry was inoculated on leaves of several herbaceous hosts grown in a greenhouse. Systemic symptoms were observed 1 to 2 weeks postinoculation in Cucumis sativus (chlorotic spots followed by systemic ringspot and leaf deformation), Chenopodium quinoa (necrotic lesions/leaf deformation), Nicotiana benthamiana (mosaic/line patterns), and N. rustica (necrotic ring spots). Electron microscopy of partially purified preparations from infected joe-pye weed and cucumber plants revealed the presence of intact and empty isometric viral particles of approximately 30 nm in diameter resembling nepoviruses or comoviruses. The original joe-pye weed plant and artificially infected herbaceous plants were tested by ELISA (Agdia Inc., Elkhart, IN) for several nepoviruses/comoviruses and found to be positive for Tobacco ringspot virus (TRSV; genus Nepovirus, family Comoviridae). Total RNA extracted from the original virus source plant was reverse transcribed using oligodT primer and submitted to PCR with the primer set TRS-F (5'TATCCCTATGTGCTTGAGAG3') and TRS-R (5'CATAGACCACCAGAGTCACA3') designed from the published sequences in GenBank of the RNA 1 of Tobacco ringspot virus. A specific 766-bp PCR product was cloned and sequenced. Sequence analysis showed that the virus from the joe-pye weed shared 94% nucleotide identity (98% at amino acid level) with a "bud blight" isolate of TRSV (Accession No U50869) (2) in the sequenced genome portion and slightly lower (90 to 92%) with other sequenced isolates of the same virus, thus further confirming the identity of the virus. In 2008 and 2009, TRSV was detected in an additional 16 symptomatic specimens of the same host collected from six distinct locations in Mississippi. Our results show that E. purpureum is a new host for TRSV. Considering that the related plant species E. capillifolium (small dogfennel) was already reported as a host of TRSV in North Carolina (1), this suggests that these two common plants may represent additional reservoirs of this virus in the region. References: (1) M. C. Rush and G. V. Gooding. Phytopathology 60:1756, 1970, (2) P. A. Zalloua et al. Virology 219:1, 1996.
紫茎泽兰(紫茎泽兰、甜紫茎泽兰和香紫茎泽兰)是一种原产于美国东部的多年生野生花卉植物。2006年5月,在密西西比州立大学校园里的一株紫茎泽兰植物上观察到了类似病毒的症状,包括系统性黄化、斑驳以及叶片向下卷曲。将有症状的幼叶在pH值为7.2的0.1M磷酸盐缓冲液中研磨,然后将浆液接种到温室中种植的几种草本寄主植物的叶片上。接种后1至2周,在黄瓜(出现褪绿斑点,随后出现系统性环斑和叶片变形)、藜麦(坏死斑/叶片变形)、本氏烟草(花叶/线状图案)和黄花烟草(坏死环斑)上观察到了系统性症状。对来自受感染的紫茎泽兰和黄瓜植株的部分纯化制剂进行电子显微镜检查,发现存在直径约为30nm的完整和空的等轴对称病毒颗粒,类似于线虫传多面体病毒或豇豆花叶病毒。通过酶联免疫吸附测定(ELISA,Agdia公司,印第安纳州埃尔克哈特)对原始的紫茎泽兰植物和人工感染的草本植物进行了几种线虫传多面体病毒/豇豆花叶病毒检测,发现它们对烟草环斑病毒(TRSV;线虫传多面体病毒属,豇豆花叶病毒科)呈阳性。从原始病毒源植物中提取的总RNA使用寡聚dT引物进行反转录,并使用根据烟草环斑病毒RNA 1在GenBank中公布的序列设计的引物对TRS-F(5'TATCCCTATGTGCTTGAGAG3')和TRS-R(5'CATAGACCACCAGAGTCACA3')进行PCR。克隆并测序了一个766bp的特异性PCR产物。序列分析表明,来自紫茎泽兰的病毒在测序的基因组部分与TRSV的一个“芽枯病”分离株(登录号U50869)(2)具有94%的核苷酸同一性(氨基酸水平为98%),与同一病毒的其他测序分离株略低(90%至92%),从而进一步证实了该病毒的身份。在2008年和2009年,从密西西比州六个不同地点采集的另外16个相同寄主的有症状标本中检测到了TRSV。我们的结果表明,紫茎泽兰是TRSV的新寄主。考虑到相关植物物种细叶泽兰(小狗茴香)在北卡罗来纳州已被报道为TRSV的寄主(1),这表明这两种常见植物可能是该地区这种病毒的额外储存库。参考文献:(1)M.C.拉什和G.V.古丁。植物病理学60:1756,1970年,(2)P.A.扎洛亚等人。病毒学219:1,1996年。