Incidence and identification of virus diseases of tobacco in three provinces of Zambia

Nine tobacco fields of small- and large-scale farmers in Central, Lusaka and Southern provinces of Zambia with an experimental area in the range of 4–52 ha were surveyed for the incidence, prevalence and identification of virus diseases during the growing season of 1997. Samples were collected from three tobacco fields in each of the three provinces, and a total of 72 samples was analysed. Virus identification was based on field disease syndrome, host range studies, DAS-ELISA and electron microscopy of virus particles in some cases. The study demonstrated the occurrence of Tobacco mosaic virus (TMV), Potato virus Y (PVY), Alfalfa mosaic virus (AMV) and Tobacco ringspot virus (TRSV). TMV and PVY occurred widely and were common in all three provinces, while AMV and TRSV were relatively less common. The prevalence of the four viruses was TMV 78%, PVY 67%, AMV 33% and TRSV 22%. Serological tests for Tomato spotted wilt virus (TSWV) and Cucumber mosaic virus (CMV) showed that these viruses were not present in the tobacco samples analysed.     

Evaluation of the status of capsicum viruses in the main growing regions of Turkey

The incidence, severity and distribution of six viruses infecting capsicum were determined in the main growing areas of Turkey during the 2004 growing season. The surveys covered 50 randomly selected capsicum fields from four different areas in south-east Anatolia and the eastern Mediterranean region. 515 samples were individually collected and tested by DAS-ELISA for Cucumber mosaic cucumovirus (CMV), Alfalfa mosaic alfamovirus (AMV), Potato X potexvirus (PVX), Potato Y potyvirus (PVY), Pepper mild mottle tobamovirus (PMMoV) and Tobacco etch potyvirus (TEV). 64.8% of ELISA-tested capsicum samples (334 out of 515) were infected by one (41.7%) or more (23.1%) viruses. PVY was the most widespread (26.4%), followed by PVX (25.8%), AMV (25.2%), TEV (23%), PMMoV (9.1%) and CMV (8.3%). Surprisingly high AMV infection was found in three areas (Kahramanmaraş, Şanlıurfa and Gaziantep) where AMV is reported for the first time in this study. However, AMV was not detected in Hatay. PMMoV is another new virus, in all the tested areas.     

Identification of the principal viruses infecting tomato crops in Tunisia

Serological tests have been used to detect viruses associated with tomato in 257 samples collected in different regions in Tunisia, Cap-Bon, Sahel and South during successive seasons. The viruses detected were cucumber mosaic cucumovirus (CMV) and tomato aspermy cucumovirus (TAV), potato Y potyvirus (PVY), tobacco etch potyvirus (TEV) and pepper veinal mottle potyvirus (PVMV), tomato mosaic tobamovirus (ToMV) and tobacco mosaic tobamovirus (TMV), tobacco rattle tobravirus (TRV), alfalfa mosaic alfamovirus (AMV), tomato spotted wilt tospovirus (TSWV), tomato ringspot nepovirus (TomRSV) and potato X potexvirus (PVX). Some were detected in all three regions surveyed, at variable frequencies: TMV, CMV, TEV, PVY, ToMV, AMV, TAV, TSWV and TRV. Others were only detected in two regions (PVMV in Cap-Bon and Sahel and PVX in Sahel and in the south) or one region (TomRSV in Cap-Bon). Movement of individual viruses from one region to another may be due to movement of specific vectors, as in the case of the thrips-transmitted TSWV moving from the south to the north. Some of these viruses were found for the first time in Tunisia.     

Occurrence of viruses in field-grown pepper crops and some of their reservoir weed hosts in Samsun, Turkey

Pepper production is affected by several viral diseases in Samsun, Turkey. To determine the identity of these viruses, a total of 313 samples from field-grown peppers were collected during surveys in 1998 and 1999, and tested by enzyme linked immunosorbent assay (ELISA). Six viruses,Alfalfa mosaic virus (AMV),Cucumber mosaic virus (CMV),Potato virus Y (PVY),Tomato mosaic virus (ToMV),Tobacco mosaic virus (TMV) andTomato spotted wilt virus (TSWV) were detected in the samples. Of 313 plants tested, 42 were doubly infected, and TMV+PVY (15.4%) was the most common double infection. This is also the first report of AMV in pepper fields in Turkey. The effect of some weed species that may act as reservoir of these viruses was also investigated in the region and of 24 weed species belonging to 15 families tested, 16 were found to be infected with at least one virus.Amaranthus retroflexus (Redroot pigweed) appeared to be a common host of CMV, PVY, ToMV, TMV and TSWV, whereasHibiscus trionum (Venice mallow) was recorded as a new weed host of PVY and TSWV. The majority of weed species found to be virus infected were very common in the pepper growing areas of the region. This indicates that pepper fields contaminated with these weeds are under risk of viral infections. http://www.phytoparasitica.org posting July 21, 2005.     

甘肃省18种药用植物病毒病调查及2种病毒病的鉴定

2012年6月至2013年9月对甘肃省宕昌县、漳县、岷县、渭源县、陇西县、临洮县等地区种植的具有疑似病毒病症状的半夏等18种药用植物进行调查及采样。采用黄瓜花叶病毒(CMV)、苜蓿花叶病毒(AMV)、烟草花叶病毒(TMV)、番茄花叶病毒(ToMV)、马铃薯Y病毒(PVY)、马铃薯X病毒(PVX)、芜菁花叶病毒(TuMV)等7种双抗体夹心免疫酶联检测(DAS-ELISA)试剂盒初检, 并对CMV和ToMV采用反转录PCR(RT-PCR)方法复检, 结果表明, 半夏、掌叶大黄和红花3种药用植物受到黄瓜花叶病毒(CMV)侵染; 马兜铃、土贝母及当归3种植物受到番茄花叶病毒(ToMV)侵染; 样品中未检测到上述其他病毒种类, 其余12种病毒样品的病原尚未确定。本研究为国内首次报道CMV病毒侵染掌叶大黄、红花, ToMV病毒侵染马兜铃、当归和土贝母。此研究为防治上述病毒病提供了依据。     

Viruses of vegetable crops in Albania

Field surveys were carried out in the main vegetable-growing areas of Western and Central Albania to evaluate the sanitary status of open-field and protected cultivations of capsicum, tomato, potato, watermelon, cucumber, courgette, aubergine, lettuce, cabbage, chicory, leek and celery. The following viruses were detected: Alfalfa mosaic alfamovirus (AMV), Cucumber mosaic cucumovirus (CMV), Potato Y potyvirus (PVY), Tomato spotted wilt tospovirus (TSWV) and Watermelon mosaic potyvirus 2 (WMV-2). The virus found most frequently was CMV and all the isolates identified were of subgroup IA. AMV was also detected in several areas and all isolates were of subgroup II, suggesting a French origin. Finally, at the time of this survey, TSWV infections appeared to be moderately relevant and absent in protected crops. This is the first documented record of AMV, CMV, PVY, TSWV and WMV-2 in Albania. No infection by Tomato yellow leaf curl begomovirus (TYLCV) or Zucchini yellow mosaic potyvirus (ZYMV) was detected during this survey.     

Yellow leaf curl and other virus diseases of tomato in Cyprus

Outdoor and greenhouse tomato plantings in the main production centres of Cyprus were surveyed for virus diseases during 1978–1982. A disease characterized by prominent leaf yellowing and curling was the most prevalent and damaging. The causal agent was identified as tomato yellow leaf curl virus (TYLCV) because it infected Datura stramonium but not the tobacco cultivars Havana 423 or Virginia, was graft-transmissible but not mechanically or seed-transmissible, and was transmitted persistently by the tobacco whitefly, Bemisia tabaci. Minimum acquisition and inoculation feeding periods were 20–30 and 10–20 min. respectively; the latent period was 21–24 h. The vector was infective for about 12 days, but there was no transovarial transmission to progeny.
Four other, mechanically transmissible, viruses were also isolated from tomato and identified on the basis of symptomatology, indicator host reactions and serology; tobacco mosaic virus (TMV), potato virus Y (PVY). potato virus X (PVX), and cucumber mosaic virus (CMV). These viruses, especially TMV, were commonly associated with mosaic symptoms and occasionally with other leaf or fruit disorders; coinfection with TYLCV occurred frequently.     

Survey of chickpea for viruses in Morocco

Chickpea was surveyed for viruses in the main growing areas of the crop in Morocco. A total of 36 fields was examined and 167 samples with symptoms suggestive of virus infection were collected. Serological testing using polyclonal antisera and monoclonal antibodies revealed the presence of the following viruses: alfalfa mosaic alfamovirus (AMV), broad bean mottle bromovirus (BBMV), broad bean stain comovirus (BBSV), bean yellow mosaic potyvirus, cucumber mosaic cucumovirus (CMV), faba bean necrotic yellows nanavirus (FBNYV), lettuce mosaic potyvirus, pea seed-borne mosaic potyvirus (PSbMV), and luteoviruses. Field symptoms of these viruses in chickpea comprised mosaics, yellowing, stunting, narrowing of leaflets and bushy growth. AMV, luteoviruses and potyviruses were found spread over the chickpea-growing regions, while BBSV, BBMV, and FBNYV were confined to some areas. Virus incidence per field varied from 1 to 40% for luteoviruses and from 1 to 20% for mosaic-inducing viruses. AMV, luteoviruses, potyviruses and CMV were detected in 89, 83, 75 and 42%, respectively, of the surveyed fields. BBMV, BBSV and FBNYV were less widespread at the national level. This is the first report of the occurrence of viruses other than CMV and BBMV in chickpea in Morocco, and the first record of the natural occurrence of BBSV and PSbMV in chickpea.     

云南、福建、湖南烟区烟草花叶病主要病毒种类检测及黄瓜花叶病毒亚组鉴定

 采用抗原直接包被和双抗体夹心酶联免疫吸附测定法(ELISA)对采自云南、福建、湖南烟区烟草花叶病样品进行了病毒种类检测,利用三抗体夹心ELISA对黄瓜花叶病毒(Cucumber mosaic virus,CMV)的亚组类型进行了鉴定。在云南采集的520个花叶病样品中,烟草花叶病毒(Tobacco mosaic virus,TMV)、CMV和马铃薯Y病毒(Potato virus Y,PVY)总检出率分别为71.74%、55.01%和6.35%;在福建采集的150个花叶病样品中,TMV、CMV和PVY的总检出率分别为94%、24.66%和8.00%;在湖南采集的74个花叶病样品中,TMV、CMV和PVY的总检出率分别为58.11%、51.35%和2.70%。部分样品为2种以上病毒复合侵染。云南、福建和湖南采集的64个CMV阳性样品中,属亚组Ⅰ的样品为57个,占89.1%;属亚组Ⅱ的样品为10个,占15.6%;其中3个样品为亚组Ⅰ和亚组Ⅱ的复合侵染。     

中国北方番茄主要病毒种类普查及TMV、CMV株系鉴定

1990—1994年,对中国北方15省(市)番茄4种主要病毒种类进行了普查,在3761份样本中,烟草花叶病毒(TMV)和黄瓜花叶病毒(CMV)的检出率分别为34.5％—65.7％和11.6％—62.6％,马铃薯X病毒(PVX)和马铃薯Y病毒(PVY)的检出率一般为10％—20％。与此同时,也对番茄上的TMV和CMV进行了与抗病毒育种紧密相关的株系分化研究,在333个TMV分离物中鉴定出0、1、2和1.2株系,以0和1株系为主,在绝大多数省(市)中分别占分离物的50％和30％以上;在232个CMV分离物中鉴定出轻花叶、重花叶、坏死和黄化株系,以轻花叶和重花叶株系为主,在绝大多数省(市)中分别占分离物的30％和50％以上,这一研究结果为番茄病毒病的综合防治和抗病毒育种提供了科学依据。     

First report of cucumber mosaic cucumovirus in banana from Pakistan

During regular surveys of banana plantations in the Sindh province of Pakistan for banana bunchy top nanavirus (BBTV), sporadic plants showing mosaic, chlorotic spots intermingled with a dark green area were observed at a few places in the districts of Thatta, Hyderabad and Nawabshah. The infected young plants were uprooted and grown in pots for 2 years to ascertain the cause of the disease. Apart from studying the development of symptoms, the infected plants were tested for the presence of BBTV, cucumber mosaic cucumovirus (CMV), chilli veinal mottle potyvirus (CVMV), tomato mosaic tobamovirus (TMV), potato X potexvirus (PVX) and potato Y potyvirus (PVY) by DAS-ELISA. Virions were also partially purified. The infected plants developed typical symptoms of CMV. All tested plants were ELISA-positive only for CMV, and a partially purified preparation revealed virus particles measuring 25–28 nm in diameter. Based on the characteristic field symptoms, serology and particle morphology, the presence of CMV in banana in Pakistan was established.     

河南省烟草病毒的小RNA测序检测

To identify viruses in Henan tobacco-planting areas, from 2015 to 2017 and 2019, 288 symptomatic tobacco samples were collected and then subjected to small RNA sequencing. Results showed that at least 7 viruses were detected from these samples which including four previously reported viruses, cucumber mosaic virus (CMV), tobacco mosaic virus (TMV), potato virus Y (PVY) and tobacco vein banding mosaic virus (TVBMV). Other three viruses, wild tomato mosaic virus (WTMV), brassica yellows virus (BrYV), and cycas necrotic stunt virus (CNSV) were firstly detected in Henan province. However, tobacco etch virus (TEV) and tobacco ringspot virus (TRSV) were not detected from these samples. In addition, CMV, TMV, PVY, TVBMV, and BrYV were the dominant viruses infecting tobacco in Henan Province.     

Viruses affecting tomato crops in Serbia

In a two-year survey (2011–2012), 3220 samples were collected and analyzed in order to determine the presence and distribution of viruses in tomato crops at 56 localities of 18 districts in Serbia. Out of 12 viruses tested, Cucumber mosaic virus (CMV), Potato virus Y (PVY), Alfalfa mosaic virus (AMV), Tomato spotted wilt virus (TSWV), Tomato mosaic virus (ToMV) and Tobacco mosaic virus (TMV) were detected in 42.1, 40, 11, 8.6, 2.3 and 1.3% of the total tested samples, respectively. The results revealed that CMV was prevalent in 2011 and PVY in 2012. CMV and PVY, apart from being predominant, were also the most widespread viruses. In general, single infections were the most frequent type of infection. Additionally, the most common mixed infections were double infections and the most prevalent combination was CMV and PVY. In 2011, the incidence of diseases and the percentage of all infection types were significantly higher than in 2012. Furthermore, in 2011, regardless of total single infections being prevalent compared to mixed infections, two prevailing viruses were commonly detected in mixed infections. The additional molecular testing of ELISA-negative samples using virus specific primers did not reveal the presence of Pepino mosaic virus (PepMV), Tomato yellow leaf curl virus (TYLC), Tomato infections chlorosis virus (TICV) and Tomato chlorosis virus (ToCV).     

Pepper mild mottle tobamovirus found infecting cultivars of Capsicum annuum in Zambia

A virus disease of Capsicum annuum was noticed on some sweet pepper cultivars grown in Lusaka Province (ZM) during the cropping season 1995/1996. Using differential indicator plants and serological tests, the virus was identified as pepper mild mottle tobamovirus (PMMV). Farms surveyed south and east of Lusaka showed plant infections ranging between 20 and 30% and 20 and 40%, respectively. This is the first report on the occurrence of PMMV on capsicum cultivars in Zambia.     

五种烟草病毒TMV、CMV、TEV、PVY及TVBMV的多重RT-PCR同步检测

 我国烟草病毒主要有烟草花叶病毒(TMV)、黄瓜花叶病毒(CMV)、烟草蚀纹病毒(TEV)、马铃薯Y病毒(PVY)和烟草脉带花叶病毒(TVBMV),通常发生复合侵染。本研究对我国5种烟草病毒的外壳蛋白基因部分序列设计引物,通过优化引物和模板浓度,摸索扩增参数,在一个体系中成功对5种病毒复合侵染的烟草材料进行多重RT-PCR扩增,得到237、273、347、456和547 bp共5条特异性条带,建立了能同时检测TMV、CMV、TEV、PVY和TVBMV的多重RT-PCR检测体系。对田间样品检测结果证明,多重RT-PCR体系能够同时检测5种病毒,并且灵敏度高。     

北京地区花生病毒病及流行规律研究

1985—1987年研究表明北京地区花生上流行的病害主要有黄瓜花叶病毒CA株系(CMV-CA)引起的黄花叶病害和花生轻斑驳病毒(PMMV)引起的轻斑驳病害。血清鉴定451份花生病害样品,黄花叶病害样品受CMV-CA侵染占95.7％,轻斑驳病害样品受PMMV侵染占91.3％,中后期病害样品受CMV-CA和PMMV复合感染较普遍。CMV种传率2％左右,种传病苗在花生出苗后开始出现,6月病害进入高峰。三年CMV-CA流行程度明显不同,主要取决于苗期蚜虫发生早晚、发生量及苗期降雨量。PMMV种传率低于1％,病苗出现稍晚,但病害扩散快,6月上旬进入高峰,7月上、中旬发病率达100％。三年流行程度差异不明显。     

从葎草中检出复合侵染的多种病毒

采用抗原直接包被酶联免疫吸附测定法（ELISA）对采自重庆近郊的34个葎草样品进行了主要病毒种类的检测。其中马铃薯Y病毒(Potato virus Y, PVY)的侵染最普遍,其阳性检出率达44.12%;马铃薯X病毒(Potato virus X, PVX)的阳性检出率最低,仅为26.47%,其余5种病毒,烟草花叶病毒(Tobacco mosaic virus, TMV)、黄瓜花叶病毒(Cucumber mosaic virus, CMV)、番茄花叶病毒(Tomato mosaic virus, ToMV)、芜菁花叶病毒(Turnip mosaic virus, TuMV)及蚕豆萎蔫病毒2号(Broad bean wilt virus 2, BBWV-2)的阳性检出率均为35.29%。葎草样品受多种病毒的复合侵染现象非常严重,15个阳性样品中病毒复合侵染率为80%,其中75%的样品检测到7种病毒复合侵染。     

Viruses in the northern potato-producing regions of Saudi Arabia

Agar double diffusion tests and, later, ELISAs were used to detect viruses associated with potato in 242 samples collected in 16 trips to Tabuk and Hail, northern regions of Saudi Arabia, in four consecutive growing seasons (autumn 1989, spring and autumn 1990 and spring 1991). Eleven different viruses were detected in Tabuk and 12 in Hail. The viruses detected in Tabuk were alfalfa mosaic (AMV), cucumber mosaic (CMV), tobacco mosaic (TMV), potato leaf roll (PLRV), tomato spotted wilt (TSWV), tobacco ringspot (TRSV) and potato A, M, S, X and Y. The same viruses, plus potato yellow dwarf (PYDV), were detected in Hail. AMV was most frequently and CMV least frequently detected in Tabuk, whereas in Hail the most and least common were PVA and PLRV respectively.     

A survey of tobacco viruses in tobacco crops and native flora in Greece

The most important tobacco producing areas in Greece were surveyed for virus presence, from 1997 to 2000. Tobacco seedlings or plants showing virus-like symptoms were randomly collected from seedbeds or fields, respectively, and tested by ELISA, and/or mechanical inoculation onto indicator plants. Potato virus Y (PVY), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV) were detected in all sampling areas, with TMV mainly found in oriental varieties. Tomato spotted wilt virus (TSWV) consisted a serious endemic virus in Northern Greece (Thrace, Central and Eastern Macedonia), whereas Alfalfa mosaic virus (AMV) was mainly found in regions, where alfalfa was cultivated in the vicinity of tobacco crops. Eggplant mottled dwarf virus (EMDV) was detected in several areas but always in very low incidence (<0.01%). Surveys were also conducted to assess the potential reservoir hosts of PVY, CMV and AMV among weeds collected from highly infected tobacco fields from 1998 to 2000. Among 3450 samples tested for PVY, plants from 17 species in 10 families were found infected. For CMV, 2891 weed samples were tested and 19 species in 12 families were positive. Assays for AMV infection were made on 961 samples and 12 species in 9 families were identified as hosts of this virus.     

Leonotis nepetaefolia: An important plant virus reservoir in central Mexico

The presence of viruses in the weedLeonotis nepetaefolia in central México is reported from two field surveys.L. nepetaefolia, with viral-like symptoms such as mosaic, leaf deformation and calico, was observed growing next to cultivated fields in the Valley of Atlixco, Puebla, an important agricultural region in Mexico. The viruses harbored by this plant were characterized biologically, serologically and by molecular methods. The viruses detected wereAlfalfa mosaic virus (AMV),Cucumber mosaic virus (CMV), a satellite RNA of CMV (CMV satRNA) andTobacco mosaic virus (TMV). This last one was detected only during the first survey. CMV was the predominant virus found in both surveys, and was associated mostly to mosaic symptom. Phylogenetic analysis based on the coat protein gene sequence of CMV indicated that this isolate belongs to subgroup IA and confirmed that it is a mosaic-inducing isolate, whereas AMV belongs to subgroup II. Finally, CMV satRNA was found to be a non-necrogenic ameliorative variant, both by symptomatology and by phylogenetic analysis. Our results suggest thatL. nepetaefolia is a reservoir for several viruses in central Mexico, and given its wide distribution in several parts of the world, its role as a virus reservoir could be more general. http://www.phytoparasitica.org posting Aug. 31, 2005.