High Similarity Between Tomato Isolates of Pepino mosaic Virus Suggests a Common Origin

The almost simultaneous outbreaks of Pepino mosaic virus in tomato crops in different European and non-European countries, was reason to have a closer look at the relationship between these isolates and the original isolate from pepino. Fifteen isolates from tomato from different locations and the original pepino isolate, were compared on the basis of their symptomatology on a series of plant species. In addition, PCR fragments derived from the viral polymerase gene were sequenced and aligned. Both studies showed that the isolates from tomato clearly differed from the pepino isolate. The different tomato isolates, however, exhibited only minor differences to each other, both in symptomatology and nucleotide sequence. These results support the conclusion that the tomato isolates should be considered as a distinct strain (Mumford and Metcalfe (2001) Archives of Virology 146: 2455–2460; Van der Vlugt et al. (2000) Plant Disease 84: 103; Van der Vlugt et al. (2002) Bulletin OEPP/EPPO Bulletin 32: 503–508). Moreover, the high similarity of the different tomato isolates suggests the existence of a common source of infection for the recent outbreaks.     

应用IC-RT-PCR方法检测番茄环斑病毒

以番茄环斑病毒阳性样品为研究材料,根据GeneBank(核酸序列数据库)中的序列设计特异性引物进行IC-RTP-CR(免疫反转录聚合酶链式反应,下同)扩增,获得产物克隆到pMD18-T载体中,经测序后与目标序列(ToRSVL19655)比较,核苷酸同源性为87.3%。通过实验建立了检测该病毒的IC-RT-PCR方法。该方法对其他样品核酸提取困难而抗体较容易制备的病毒检测同样具有借鉴意义。     

Comparison and differentiation of Wheat Yellow Mosaic Virus(WYMV), Wheat Spindle Streak Mosaic Virus (WSSMV) and Barley Yellow Mosaic Virus (BaYMV) isolates using WYMV monoclonal antibodies

Twelve monoclonal antibodies (MAbs) were obtained by immunizing mice with a French isolate (F1) of wheat yellow mosaic virus (WYMV). Three of these (3D12, 2C1, 6C3) belong to the IgM class and the nine others to the IgG class (3D8, 3H1, 2B8, 1F2, 3C10, 4F12, 3H9, 1G5, 54). In antigen-coated plate (ACP) ELISA and indirect double antibody sandwich (IDAS) ELISA, all MAbs recognize the WYMV (F1) both in the form of purified particles and in wheat leaf extract. The analysis of numerous French isolates of WYMV shows a variable reactivity with MAbs 3D8, 3H1, 2B8, 3C10, 3H9 and 1G5 in IDAS — and ACP-ELISA. The Japanese isolate of WYMV and United States isolates of wheat spindle streak mosaic virus (WSSMV) were detected in IDAS- and ACP-ELISA by ten of the MAbs tested showing that the wheat bymoviruses originating from the three locations share a high epitopic homology. French isolates of barley yellow mosaic virus (BaYMV; pathotypes 1 and 2) were only detected in ACP-ELISA with MAbs 6C3, 3D8, 3H1 and 2B8 whereas the two Japanese strains (I-1, II-1) of MaYMV were recognized with these and also with that of 3C10. In IDAS-ELISA, the two Japanese strains were clearly detected by MAbs, 6C3, 3D8, 3H1, 1F2, 3C10 and 1G5 and the British and Belgian (pathotype 2) isolates only by that of 6C3. Only the Japanese strain of BaYMV, 1-1 could be detected with MAb 3H9 in this ELISA system.     

Genetic variation and evolutionary analysis of Pepino mosaic virus in Sicily: insights into the dispersion and epidemiology

Pepino mosaic virus (PepMV) is a highly infectious potexvirus that causes a severe disease in tomato (Solanum lycopersicum) crops worldwide. In Sicily, the first outbreak was detected in a single greenhouse in 2005 and it was promptly eradicated. However, in 2008, a large number of greenhouses were simultaneously affected, and it was impossible to eradicate or control the virus. This study addressed the dispersion and the genetic diversity of PepMV isolates obtained from the outbreak in Sicily, in comparison with worldwide PepMV isolates, to gain insight into the factors determining the evolution and epidemiology of the virus. A total of 1800 samples from plants with and without symptoms were collected in the Sicilian provinces of Agrigento, Caltanissetta, Palermo, Ragusa, Siracusa and Trapani. Three isolates collected at different times were biologically characterized. The incidence of the virus increased rapidly from 13% in 2011 to 63% in 2013, and phylogenetic analysis showed that all Sicilian isolates of PepMV belonged to the CH2 strain, one of the six strains previously described. Nucleotide diversity of the Sicilian isolates was low, thus suggesting rapid spread and genetic stability.     

葡聚六糖诱导烟草抗花叶病毒病的研究

分别采用酶联免疫吸附技术(Fab’)2-ELISA和温室盆栽试验测定了葡聚六糖诱导烟草对花叶病毒病的抗性,结果表明,葡聚六糖诱导烟草抗花叶病毒病的最佳有效浓度为10 μg/mL,最佳诱导间隔期为7 d,持效期约为28 d,诱导抗病的防病效果与诱导次数呈正比。     

The Components and Deployment of Resistance to Cassava Mosaic Virus Disease

Cassava mosaic virus disease (CMD) is prevalent and causes serious losses in cassava (Manihot esculenta) in southern India and in many parts of sub-Saharan Africa. The disease is caused by viruses of the Geminiviridae that are transmitted by the whitefly Bemisia tabaci and disseminated in the stem cuttings used routinely for propagation. The main approach to control is through the use of virus-resistant varieties, but suitable ones are not always available and susceptible varieties are still widely grown. This explains why CMD continues to be a problem in many areas.CMD-resistant varieties have several features which are considered in this review:- They are not readily infected, even when exposed to large amounts of vector-borne inoculum. When infected they develop symptoms that tend to be inconspicuous and not associated with obvious deleterious effects on growth or yield. Moreover, the symptoms become even less conspicuous as growth proceeds and plants may eventually recover and become symptomless. Infected plants support a low virus content and they are likely to be a poor source of inoculum from which further spread can occur. Virus is not fully systemic within infected plants which can be a source of uninfected planting material when stem cuttings are collected for further propagation. This phenomenon is referred to as reversion and it has an important cleansing effect in restricting or preventing the progressive deterioration in health status that would otherwise occur during successive cycles of vegetative propagation.The available information on the different components of resistance is discussed and it is concluded that they are inter-related features of the same basic mechanism that restricts virus entry, replication and movement within the host. It is argued that the effectiveness and durability of virus-resistant varieties are likely to be influenced by the way in which they are deployed. However, this topic has received little attention from researchers and there is continuing uncertainty on the effects of CMD on the yield of resistant varieties and on the role of phytosanitation. This involves the use of virus-free planting material and the removal (roguing) of any additional diseased plants that occur. Some consider that these procedures complement the use of virus-resistant varieties and should be adopted, whereas others argue that they are unnecessary and inappropriate. It is concluded that there is considerable scope for utilizing resistant varieties more widely and more effectively than at present, but in doing so it is important to avoid eroding the genetic diversity that is currently such a marked feature of cassava cultivation in Africa.     

影响大豆花叶病毒种子传毒和种子斑駁因素的研究

 本文研究了影响大豆花叶病毒种子传毒及种子斑驳的有关因素,以及种子传毒与种子斑驳的关系。结果表明,种子传毒率的高低受大豆品种,大豆花叶病毒(SMV)毒株,大豆感病早晚以及环境条件的影响。这些因素之间对种子传毒还存在交互作用。供试的12个大豆品种中,传毒率最高的为47%,最低的为25%;包括SMV Ⅰ,Ⅱ,Ⅲ号3个株系群的8个毒株在东农64-3513上传毒率的变化范围为1-33%,在抗霉2号上的变化范围为9-48%;大豆在开花以前感染SMV,种子传毒率可达45%,开花以后感病,种子基本不能传毒。
种子斑驳率因大豆品种,SMV毒株不同而异,并受品种与毒株交互作用的影响。种子斑驳既不代表种子带毒,也不代表种子传毒;从感病植株上采收的大豆种子,其斑驳种子与非斑驳种子的传毒率基本相同(P>0.05),因此,不能从种子斑驳率预测种子传毒率。     

利用实时荧光RT-PCR方法检测番茄环斑病毒和烟草环斑病毒

根据番茄环斑病毒和烟草环斑病毒各分离物CP基因的保守序列分别设计并合成1对引物和1条TaqMan荧光探针,分别建立了ToRSV和TRSV的实时荧光RT-PCR检测方法。该方法具有更加灵敏、特异、快速和简便的特点,在口岸病害检疫中具有广泛的应用前景。     

警惕新发病毒番茄褐色皱果病毒Tomato brown rugose fruit virus对我国番茄产业的危害

番茄褐色皱果病毒Tomato brown rugose fruit virus (ToBRFV)于2014年首次在以色列发现, 随后传播到欧洲、美洲以及亚洲等地。ToBRFV在番茄叶片上引起花叶, 更重要的是在番茄果实上引起褐色皱缩斑, 导致番茄完全失去商品价值, 是番茄安全生产的重大威胁。为遏制ToBRFV的传播, 多个国家已经将该病毒列入检疫对象。2019年, 我们在山东番茄上检测到该病毒。本文综述了ToBRFV发生与危害、寄主范围和症状、传播方式、基因组结构、检测方法, 并提出了防治建议, 希望有助于防范该病毒在我国的扩散。     

核多角体病毒侵染棉铃虫中肠细胞的观察

应用电子显微镜技术观察了核多角体病毒入侵棉铃虫中肠细胞及其增殖和释放，经口接种后30min，有许多病毒粒子进入中肠后部柱状细胞的微绒毛间隙处，且以其粒子的一端与微绒毛接触并吸附在微绒毛表面上，接种后1h，病毒粒子的囊膜与微绒毛的质膜以顶端对顶端、顶端对侧面发生融合，仅以核衣壳侵入细胞内，然后又继续移至微绒毛底部，从而进入中肠细胞内，此外，还发现有的病毒粒子直接与柱状细胞的质膜融合，侵入中肠细胞，在中肠细胞内增殖的病毒极少观察到被囊膜包住。     

马铃薯A病毒CP基因的克隆与序列分析

利用根据马铃薯A病毒 (PVA)外壳蛋白 (CP)基因序列设计合成的一对引物 ,以带毒植物总RNA为模板 ,RT-PCR扩增得到长 0.8kb的目的片段。将目的片段转入大肠杆菌并进行了序列测定。测序结果与PVA其他分离物CP基因序列比较 ,发现其核苷酸同源性最高可达 99%。依据CP序列建立了PVA病毒的系统进化树并对PVA不同分离物CP氨基酸序列差异性做了分析     

利用实时荧光定量PCR技术检测樱桃叶斑驳病毒

樱桃叶斑驳病毒(Cherry mottle leaf virus,CMLV)是南美洲樱桃上重要的病害之一。本研究针对Genbank上公布的该病毒的核酸序列,人工合成了CMLV(AF170028.1)6741～7322 nt的核酸序列并连接载体,构建了阳性标准质粒,进行实时荧光定量PCR(Fluorescence quantitative,FQ-PCR)检测。实验结果表明,本研究设计的利用FQ-PCR检测CMLV的引物及探针特异性良好,经灵敏度检测,最低检测浓度为23 copies/μL,比普通PCR检测灵敏度高100倍。该FQ-PCR检测方法为樱桃叶斑驳病毒的防控提供了重要的技术支持。     

Complete Nucleotide Sequence of Ryegrass Mottle Virus : A New Species of the Genus Sobemovirus

The genome of Ryegrass mottle virus (RGMoV) comprises 4210 nucleotides. The genomic RNA contains four open reading frames (ORFs). The largest ORF 2 encodes a polyprotein of 947 amino acids (103.6 kDa), which codes for a serine protease and an RNA-dependent RNA polymerase. The viral coat protein is encoded on ORF 4 present at the 3′-proximal region. Other ORFs 1 and 3 encode the predicted 14.6 kDa and 19.8 kDa proteins of unknown function. The consensus signal for frameshifting, heptanucleotide UUUAAAC and a stem-loop structure just downstream is in front of the AUG codon of ORF 3. Analysis of the in vitro translation products of RGMoV RNA suggests that the 68 kDa protein may represent a fusion protein of ORF 2-ORF 3 produced by frameshifting. The protease region of the polyprotein and coat protein have a low similarity with that of the sobemoviruses (approximately 25% amino acid identity), while the RNA-dependent RNA polymerase region has particularly strong similarity (54 to 60% of more than 350 amino acid residues). The sequence similarities of RGMoV to the sobemoviruses, together with the characteristic genome organization indicate that RGMoV is a new species of the genus Sobemovirus. Received 28 June 2000/ Accepted in revised form 14 November 2000     

北京地区番茄黄化曲叶病病毒分离物测定及株系的初步鉴定

 番茄黄化曲叶病毒病是番茄生产中的一种毁灭性病毒病害,2009年传入北京。利用烟粉虱传双生病毒简并引物PA/PB对2010年~2011年采集自北京市5个区县的53个番茄样品进行检测,30个表现典型黄化曲叶病症状的样品均扩增得到约500 bp的特异条带,测定了其中7个样品的部分序列,经序列比对分析表明其为番茄黄化曲叶病毒（Tomato yellow leaf curl virus, TYLCV）。利用TYLCV特异引物TJ-F/TJ-R、TY-F/TY-R对样品BJDXXY、BJFS02、BJFS03、BJMY2231进行TYLCV基因组克隆和序列测定,经分析4个样品携带的TYLCV基因组长度均为2 781碱基,编码6个蛋白。基因组序列比较发现,这4个分离物与TYLCV-Israel株系同源性达到98%以上;通过建立系统发育树,发现BJDXXY、BJFS02、BJFS03与河北分离物（HBLF4）、山东分离物（SDSG）亲缘关系较近,BJMY2231与上海分离物（TYLCV-Israel）、江苏分离物（JSNJ1）亲缘关系较近。     

番茄斑萎病毒核衣壳蛋白基因的克隆与分析

从云南表现褪绿黄化症状的番茄上分离到番茄斑萎病毒(Tomato spotted wilt virus)YN-1株系,利用RT-PCR方法克隆了该株系的核衣壳蛋白基因,并测定了该基因的序列,全长为777 bp,编码258个氨基酸。对该基因的氨基酸序列分析结果表明,YN-1 N基因与韩国3个株系的氨基酸序列相似性均高达97%。     

福建马铃薯S病毒的分子鉴定及发生情况

为明确福建省马铃薯S病毒(PVS)的发生与分布情况,对福建省马铃薯主要种植区的PVS进行了鉴定和普查.在利用电镜技术和传统生物学方法鉴定的基础上,克隆了PVS外壳蛋白(cp)基因,依据PVS外壳蛋白氨基酸序列建立了PVS不同分离物的系统进化树.研究表明,利用PVS 外壳蛋白氨基酸序列分析可准确鉴定PVS,同时可分析不同分离物间的分子差异.利用病毒特异性引物和DIG标记的PVS cp基因为探针,分别利用RT-PCR技术和核酸斑点杂交技术(NASH)对PVS进行了检测,并对检测技术进行了改进.调查结果表明,PVS在福建省广泛分布,发病率最高可达80%以上,当地农家自留种可能是田间PVS的主要来源.