Fruit Distortion Mosaic Disease of Okra in India

Okra (Abelmoscus esculentus (L.) Moench) is an important vegetable crop of India and other subropical and tropical countries. In 2000 and 2001, in the states of Karnataka and Tamil Nadu, okra was severely affected by a new disease. Since that time, the disease has spread to other states: Andhra Pradesh, Madhya Pradesh, Haryana, and Maharashtra. Chlorotic spots, chlorotic leaf blotches, distortion of leaves, chlorotic streaking, distortion of fruits, and severe yield losses as much as 63% characterize the disease. The causal virus induces local and systemic chlorotic and necrotic lesions on Vigna unguiculata (L.) Walp. cv. C-152 and Chenopodium amaranticolor Coste & Reyne., chlorotic local lesions and mosaic on Cucumis sativus L., necrotic local lesions on Gossypium hirsutum L. and black gram (Vigna mungo L.), and chlorotic local lesions and systemic necrosis on sunflower (Helianthus annuus L.). Host reactions on these species are similar to those described for the ilarvirus Tobacco streak virus (TSV) (3). Electron microscopic observation of leafdip preparations from field samples and partially purified virus preparations revealed the presence of isometric virus particles measuring 25 to 30 nm in diameter. The virus was purified from mechanically inoculated okra by differential and sucrose density gradient centrifugation, and disease symptoms were reproduced in okra mechanically inoculated with the purified virus. In direct antigen coated enzyme-linked immunosorbent assay and immunosorbent electron microscopy tests, the purified virus and sap extracts reacted positively with polyclonal antibodies to TSV, the ilarvirus associated with sunflower necrosis and peanut stem necrosis diseases (1,2), but did not react positively to Turnip mosaic virus and Okra mosaic virus that are previously reported to infect okra. In reverse transcription-polymerase chain reaction (RT-PCR), using oligonucleotide primers designed to amplify the entire coat protein region of TSV, an approximately 800-bp DNA fragment was obtained from purified virus and okra displaying fruit distortion mosaic disease (OFDM) but not from healthy okra. On the basis of host range, serological relationship, electron microscopy, and RTPCR amplification, the virus causing OFDM is an ilarvirus closely related to TSV. To our knowledge, this is the first report of the occurrence of an ilarvirus in okra, and is the third and most recent report of an ilarvirus related to TSV causing disease in crops on the Indian subcontinent (1,2). References:(1). A. I. Bhat et al. Arch. Virol. 147:651, 2002. (2). A. S. Reddy et al. Plant Dis. 86:173, 2002. (3). S. W. Scott. Tobacco streak virus. No 381 in: Descriptions of Plant Viruses. CMI/AAB, Surrey, U.K., 2001.

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First Report of Parietaria mottle virus on Tomato in Spain

Plant Disease ◽

10.1094/pdis.2001.85.11.1210c ◽

2001 ◽

Vol 85 (11) ◽

pp. 1210-1210 ◽

Cited By ~ 18

Author(s):

J. Aramburu

Keyword(s):

Mosaic Virus ◽

Polyclonal Antiserum ◽

Mottle Virus ◽

Tomato Mosaic Virus ◽

Tobacco Streak Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Streak Virus ◽

Range Data ◽

Local Lesions ◽

Plant Pathol

During spring 2001, plants of different tomato (Lycopersicon esculentum) cultivars grown in several commercial fields in the eastern Catalonia Region of Spain had fruit with brown patches and young leaves with rings and a bright necrotic mosaic that progressed to stem necrosis of the apex, which might die and later develop new symptomless shoots. The symptoms were similar to those of Cucumber mosaic virus (CMV) and Tomato spotted wilt virus (TSWV). Sap of tomato sample R1 (in buffered saline [0.02 M sodium phosphate, 0.15 M NaCl at pH 7.2, containing 0.2% 2-mercaptoethanol]) was infective to Cucumis sativus (local necrosis), tomato cv. Marmande (systemic infection consisting of chlorotic local lesions and necrotic mosaic), Nicotiana clevelandii and N. benthamiana (chlorosis and rosetting), and Chenopodium quinoa (chlorotic local lesions, systemic mottle, and leaf distortion). The sap was not infective to N. glutinosa, N. tabacum cv. Xanthi, Datura stramonium, or Gomphrena globosa. The host range data indicated that the infective agent in sample R1 could be Parietaria mottle virus (PMoV) (1). Symptomatic plants inoculated in a greenhouse with the R1 isolate and symptomatic from tomato plants from the field were analyzed by indirect enzyme-linked immunosorbent assay (ELISA) and had minimum ELISA values at least 10-fold higher than healthy controls, using a polyclonal antiserum (provided by P. Roggero) of a tomato strain of PMoV denoted tomato virus 1 (2). The R1 isolate of PMoV was negative in ELISA when analyzed with commercial antisera to TSWV, CMV, Tomato mosaic virus, Tomato bushy stunt virus, Potato Y virus, Tobacco etch virus, Pelargonium zonate spot virus, and Tobacco streak virus. References: (1) P. Caciagli et al. Plant Pathol. 38:577, 1989. (2) P. Roggero et al. J. Plant Pathol. 82:159, 2000.

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First Report of Tobacco Streak Ilarvirus from Honeysuckle

Plant Disease ◽

10.1094/pdis.1998.82.12.1402b ◽

1998 ◽

Vol 82 (12) ◽

pp. 1402-1402 ◽

Cited By ~ 2

Author(s):

H. E. Waterworth

Keyword(s):

Chenopodium Quinoa ◽

Alfalfa Mosaic Virus ◽

Plant Viruses ◽

Tobacco Streak Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Late Winter ◽

Streak Virus ◽

Local Lesions ◽

Quarantine Station ◽

Young Leaves

A honeysuckle (Lonicera fragrantissima) shrub on the grounds of the former Plant Quarantine Station, Glenn Dale, MD, had chlorotic leaves on some shoot tips and a mild veinal chlorosis. Young leaves were triturated in buffer and rub-inoculated onto a series of potential indicator hosts. The virus incited necrotic local lesions and necrosis of the growing point in Chenopodium quinoa, etched ringspots on inoculated leaves of Nicotiana tabacum Xanthi nc, mosaic in Zinnia violacea, and chlorotic local lesions in Tetragonia tetragonioides. It did not infect any of 46 other herbaceous genera in families Cucurbitaceae, Fabaceae, Asteraceae, Solanaceae, or Brassicaceae. In gel diffusion tests with symptomatic leaves from tobacco, this virus reacted with antiserum to tobacco streak virus (TSV) HR strain, but did not react with antisera to alfalfa mosaic or with antisera to 12 viruses in the NEPO or Sobemovirus groups. Virus in leaves directly from the source shrubs, tested by enzyme-linked immunosorbent assay (ELISA), also reacted with TSV strain HF antiserum. Examination by electron microscopy of leaf dips revealed isometric particles 27 nm in diameter. The now 12-ft tall shrubs were grown from seed imported from China in 1914 (PI 40689). This species is now widely commercially available in the U.S. and grown for its fragrant late winter flowers (2). Viral-infected Lonicera spp. have been reported from Europe, Russia, Japan, and Canada (1). TSV is reported to be seed-borne in several other genera. Among other viruses reported from honeysuckle are Lonicera latent carlavirus, tobacco leaf curl geminivirus, alfalfa mosaic virus, tomato bushy stunt virus, a rhabdovirus, and an aphid transmitted virus. References: (1) R. W. Fulton. CMI/AAB Descriptions of Plant Viruses No. 307, 1985. (2) C. J. Perkin. Plantsman 12:215, 1991.

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Development of a triple antibody sandwich enzyme-linked immunosorbent assay for cassava mosaic disease detection using a monoclonal antibody to Sri Lankan cassava mosaic virus

Virology Journal ◽

10.1186/s12985-021-01572-6 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Saengsoon Charoenvilaisiri ◽

Channarong Seepiban ◽

Mallika Kumpoosiri ◽

Sombat Rukpratanporn ◽

Nuchnard Warin ◽

...

Keyword(s):

Mosaic Virus ◽

Immunosorbent Assay ◽

Mosaic Disease ◽

Cassava Mosaic Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Sri Lankan ◽

Stem Cuttings ◽

Field Samples ◽

Cassava Stem ◽

Cassava Mosaic Virus

Abstract Background Cassava mosaic disease (CMD) is one of the most devastating viral diseases for cassava production in Africa and Asia. Accurate yet affordable diagnostics are one of the fundamental tools supporting successful CMD management, especially in developing countries. This study aimed to develop an antibody-based immunoassay for the detection of Sri Lankan cassava mosaic virus (SLCMV), the only cassava mosaic begomovirus currently causing CMD outbreaks in Southeast Asia (SEA). Methods Monoclonal antibodies (MAbs) against the recombinant coat protein of SLCMV were generated using hybridoma technology. MAbs were characterized and used to develop a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) for SLCMV detection in cassava leaves and stems. Assay specificity, sensitivity and efficiency for SLCMV detection was investigated and compared to those of a commercial ELISA test kit and PCR, the gold standard. Results A TAS-ELISA for SLCMV detection was successfully developed using the newly established MAb 29B3 and an in-house polyclonal antibody (PAb) against begomoviruses, PAb PK. The assay was able to detect SLCMV in leaves, green bark from cassava stem tips, and young leaf sprouts from stem cuttings of SLCMV-infected cassava plants without cross-reactivity to those derived from healthy cassava controls. Sensitivity comparison using serial dilutions of SLCMV-infected cassava sap extracts revealed that the assay was 256-fold more sensitive than a commercial TAS-ELISA kit and 64-fold less sensitive than PCR using previously published SLCMV-specific primers. In terms of DNA content, our assay demonstrated a limit of detection of 2.21 to 4.08 × 106 virus copies as determined by quantitative real-time PCR (qPCR). When applied to field samples (n = 490), the TAS-ELISA showed high accuracy (99.6%), specificity (100%), and sensitivity (98.2%) relative to the results obtained by the reference PCR. SLCMV infecting chaya (Cnidoscolus aconitifolius) and coral plant (Jatropha multifida) was also reported for the first time in SEA. Conclusions Our findings suggest that the TAS-ELISA for SLCMV detection developed in this study can serve as an attractive tool for efficient, inexpensive and high-throughput detection of SLCMV and can be applied to CMD screening of cassava stem cuttings, large-scale surveillance, and screening for resistance.

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Assessment of Common Soybean-Infecting Viruses in Ohio, USA, Through Multi-site Sampling and High-Throughput Sequencing

Plant Health Progress ◽

10.1094/php-rs-16-0018 ◽

2016 ◽

Vol 17 (2) ◽

pp. 133-140 ◽

Cited By ~ 1

Author(s):

Junping Han ◽

Leslie L. Domier ◽

Bryan J. Cassone ◽

Anne Dorrance ◽

Feng Qu

Keyword(s):

Mosaic Virus ◽

High Throughput ◽

High Throughput Sequencing ◽

Virus Disease ◽

Soybean Mosaic Virus ◽

Alfalfa Mosaic Virus ◽

Plant Viruses ◽

Yellow Mosaic Virus ◽

Tobacco Streak Virus ◽

Streak Virus

Multi-site sampling was conducted during 2011 and 2012 to assess the scope of virus disease problems of soybean in Ohio, USA. A total of 259 samples were collected from 80 soybean fields distributed in 42 Ohio counties, accounting for more than 90% of major soybean-growing counties in Ohio. A high-throughput RNA-Seq approach was adopted to identify all viruses in the samples that share sufficient sequence similarities with known plant viruses. To minimize sequencing costs, total RNA extracted from up to 20 samples were first pooled to make up regional pools, resulting in eight regional pools per year in both 2011 and 2012. These regional pools were further pooled into two yearly master pools of RNA, and sequenced using the Illumina's HiSeq2000 platform. Bioinformatic analyses of sequence reads led to the identification of signature sequences of nine different viruses. The originating locations of these viruses were then mapped with PCR or RT-PCR. This study confirmed the widespread distribution of Bean pod mottle virus, Soybean vein necrosis virus, Tobacco ringspot virus, and Tobacco streak virus in Ohio. It additionally revealed occasional association of Alfalfa mosaic virus, Bean yellow mosaic virus, Clover yellow vein virus, Soybean mosaic virus, and Soybean Putnam virus with Ohio soybean. This is the first statewide survey of soybean viruses in Ohio, and provides the much-needed baseline information for management of virus diseases of soybean. Accepted for publication 20 May 2016. Published 10 June 2016.

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A New Ilarvirus Isolated from Grapevine in Greece

Plant Disease ◽

10.1094/pdis.2000.84.12.1345c ◽

2000 ◽

Vol 84 (12) ◽

pp. 1345-1345 ◽

Cited By ~ 2

Author(s):

S. M. Girgis ◽

F. Bem ◽

P. E. Kyriakopoulou ◽

C. I. Dovas ◽

A. P. Sklavounos ◽

...

Keyword(s):

Sequence Data ◽

Sequence Similarity ◽

Infected Plant ◽

Chenopodium Quinoa ◽

Tobacco Streak Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Streak Virus ◽

Degenerate Primers ◽

Severe Stunting ◽

Local Lesions

In 1994, characteristic viruslike symptoms on grapevine were reported in the collection of the Grapevine Institute in Athens, Greece, on the hybrid Baresana × Baresana. The symptoms were sharp angular mosaic, leaf crinkle, and little leaf. The affected vines showed gradual decline and severe stunting or death. Such vines produced abortive flowers or very few berries with smaller, wrinkled, and nongerminating seeds. Serological testing, by enzyme-linked immunosorbent assay (ELISA), of the affected vines against the most common grapevine viruses Alfalfa mosaic, Arabis mosaic, Grapevine fanleaf, Grapevine fleck, Grapevine A, Rasberry ringspot, and grapevine leafroll-associated viruses gave negative results. A virus was isolated from affected grapevine young leaves by mechanical inoculation of Gomphrena globosa and single lesioned. The virus host range included G. globosa (local and systemic dark red or necrotic lesions), Chenopodium quinoa (necrotic local lesions and systemic mottle), and three tobacco cultivars (sharp necrotic local lesions, 1 to 3 mm in diameter). Pollination of C. quinoa with pollen from infected plant gave about 30% infected seedlings. The virus was purified from C. quinoa by differential centrifugation using 0.02 M phosphate buffer pH 8.0, containing 0.01 M DIECA and 0.01 M sodium thioglycolate as extraction buffers. In a purified preparation, quasisphaerical virus particles of about 29 nm were observed. Electrophoretic mobility of the viral coat protein showed a molecular weight of 30 kDa. Using purified preparations, an antiserum was obtained with a titer of 1:1024 in microprecipitin test and an optimum IgG dilution in ELISA of 1:10,000 for maximum absorption at OD405 nm Using degenerate primers designed from homologous regions in RNA-2 corresponding to a fragment of the polymerase gene of Ilarviruses, the expected 381-bp polymerase chain reaction product was obtained. This product was cloned and sequenced. Comparisons with sequence data from the homologous regions of RNA-2 of other known Ilarviruses, showed that the sequence of the above 381-bp amplicon shared 72% sequence similarity with Tobacco streak virus, 67% of Citrus variegation virus and Spinach latent virus, 66% of Asparagus virus 2 and Elm mottle virus, and 65% of Citrus leaf rugose virus. Based on the above data, it is concluded that the isolated virus is an Ilarvirus with closest similarity to Tobacco streak virus. From the relative bibliography (1–3) it appears that the virus reported here is different from Grapevine line pattern virus, a possible Ilarvirus, previously reported from Hungary. References: (1) J. Lehoczky et al. Kertgazdasag 19:61, 1987. (2) J. Lehoczky et al. Phytoparasitica 17:59, 1989. (3) J. Lehoczky et al. Phytopathol. Medit. 31:115, 1992.

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Occurrence and Relative Incidence of Viruses Infecting Soybeans in Iran

Plant Disease ◽

10.1094/pdis.2004.88.10.1069 ◽

2004 ◽

Vol 88 (10) ◽

pp. 1069-1074 ◽

Cited By ~ 28

Author(s):

A. R. Golnaraghi ◽

N. Shahraeen ◽

R. Pourrahim ◽

Sh. Farzadfar ◽

A. Ghasemi

Keyword(s):

Mosaic Virus ◽

Soybean Mosaic Virus ◽

Alfalfa Mosaic Virus ◽

Soybean Seed ◽

Ringspot Virus ◽

Yellow Mosaic Virus ◽

Tobacco Streak Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Streak Virus ◽

Natural Occurrence

A survey was conducted to determine the incidence of Alfalfa mosaic virus (AlMV), Bean common mosaic virus (BCMV), Bean yellow mosaic virus (BYMV), Blackeye cowpea mosaic virus (BlCMV), Cucumber mosaic virus (CMV), Pea enation mosaic virus (PEMV), Peanut mottle virus (PeMoV), Soybean mosaic virus (SMV), Tobacco mosaic virus (TMV), Tobacco ringspot virus (TRSV), Tobacco streak virus (TSV), Tomato ringspot virus (ToRSV), and Tomato spotted wilt virus (TSWV) on soybean (Glycine max) in Iran. Totals of 3,110 random and 1,225 symptomatic leaf samples were collected during the summers of 1999 and 2000 in five provinces of Iran, where commercial soybean is grown, and tested by enzyme-linked immunosorbent assay (ELISA) using specific polyclonal antibodies. Serological diagnoses were confirmed by electron microscopy and host range studies. The highest virus incidence among the surveyed provinces was recorded in Mazandaran (18.6%), followed by Golestan (15.7%), Khuzestan (14.2%), Ardabil (13.9%), and Lorestan (13.5%). Incidence of viruses in decreasing order was SMV (13.3%), TSWV (5.4%), TRSV (4.2%), TSV (4.1%), PEMV (2.9%), BYMV (2.2%), ToRSV (2.1%), AlMV (1.3%), BCMV (0.8%), and CMV (0.6%). Additionally, 1.5% of collected leaf samples had positive reactions in ELISA with antiserum to TMV, indicating the possible infection of soybeans in Iran with a Tobamovirus that is related serologically to TMV. Of 195 leaves from plants showing soybean pod set failure syndrome (PSF) in Mazandaran and Lorestan, only 14 (7.2%) samples had viral infection. No correlation was observed between PSF and presence of the 13 viruses tested, suggesting the involvement of other viruses or factors in this syndrome. To investigate the presence of seed-borne viruses, including SMV, TRSV, ToRSV, and TSV, 7,830 soybean seeds were collected randomly at harvesting time from the major sites of soybean seed production located in Mazandaran and Golestan provinces. According to ELISA analyses of germinated seedlings, 7.1 and 8.9% of the seed samples from Golestan and Mazandaran provinces, respectively, transmitted either SMV, TRSV, ToRSV, or TSV through seed. We also showed that SMV and other seed transmissible viruses, as well as TSWV, usually are the most prevalent viruses in soybean fields in Iran. In this survey, natural occurrence of AlMV, BCMV, BlCMV, BYMV, CMV, PEMV, PeMoV, and TSWV was reported for the first time on soybeans in Iran.

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Occurrence of Radish mosaic virus on Cauliflower and Turnip Crops in Iran

Plant Disease ◽

10.1094/pdis.2004.88.8.909a ◽

2004 ◽

Vol 88 (8) ◽

pp. 909-909 ◽

Cited By ~ 5

Author(s):

S. Farzadfar ◽

R. Pourrahim ◽

A. R. Golnaraghi ◽

S. Jalali ◽

A. Ahoonmanesh

Keyword(s):

Mosaic Virus ◽

Brassica Rapa ◽

Polyclonal Antibodies ◽

The United States ◽

Plant Viruses ◽

Enzyme Linked Immunosorbent Assay ◽

Leaf Extracts ◽

Chenopodium Amaranticolor ◽

Local Lesions ◽

Ring Spot

During the spring and summer of 2003, symptoms of mosaic, mottle, and crinkle were observed in cauliflower (Brassica oleracea) and turnip (Brassica rapa) fields in the Qazvin and Esfahan provinces of Iran, respectively. Leaf extracts of these plants, made infective by mechanical inoculation, caused necrotic local lesions on Chenopodium amaranticolor, chlorotic ring spot on Nicotiana tabacum cv. Samsun, and chlorotic local lesions followed by systemic mosaic on Brassica rapa (1). Using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and specific polyclonal antibodies (As-0120 and PV-0355) that were kindly prepared by S. Winter (DSMZ, Braunschweig, Germany), the samples were tested for the presence of Radish mosaic virus (RaMV) (family Comoviridae, genus Comovirus). ELISA results showed that the original leaf samples and inoculated indicator plants reacted positively to RaMV antibodies. RaMV has been reported in the United States, Japan, and Europe on turnip and other crucifers (1,2). To our knowledge, this is the first report of RaMV occurring in Iran. References: (1) R. N. Campbell. Radish mosaic virus. No. 121 in: Descriptions of Plant Viruses. CMI/AAB, Surrey, England, 1973. (2) D. D. Sutic et al. Handb. Plant Virus Diseases. CRC Press, Boca Raton, FL, 1999.

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Incidence of Viruses Infecting Tomato and Their Natural Hosts in the Southeast and Central Regions of Iran

Plant Disease ◽

10.1094/pdis-93-1-0067 ◽

2009 ◽

Vol 93 (1) ◽

pp. 67-72 ◽

Cited By ~ 12

Author(s):

Hossain Massumi ◽

Mehdi Shaabanian ◽

Akbar Hosseini Pour ◽

Jahangir Heydarnejad ◽

Heshmetollah Rahimian

Keyword(s):

Mosaic Virus ◽

Potato Virus ◽

Tomato Mosaic Virus ◽

Tobacco Streak Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Streak Virus ◽

Arabis Mosaic Virus ◽

Potato Virus S ◽

Chlorotic Spot ◽

Central Regions

A survey was conducted to determine the incidence of Cucumber mosaic virus (CMV), Beet curly top virus (BCTV), Tomato yellow leaf curl virus (TYLCV), Tomato chlorotic spot virus (TcSV), Potato virus Y (PVY), Potato virus S (PVS), Tomato spotted wilt virus (TSWV), Tomato ringspot virus (TRSV), Tomato aspermy virus (TAV), Arabis mosaic virus (ArMV), Tobacco streak virus (TSV), Tomato bushy stunt virus (TBSV), Tobacco mosaic virus (TMV), and Tomato mosaic virus (ToMV) on tomato (Solanum lycopersicum) in the major horticultural crop growing areas in the southeast and central regions of Iran. A total of 1,307 symptomatic leaf samples from fields and 603 samples from greenhouses were collected from January 2003 to July 2005 in five southeastern and central provinces of Iran. Samples of symptomatic plants were analyzed for virus infection by enzyme-linked immunosorbent assay (ELISA) using specific polyclonal antibodies. ArMV and CMV were the most frequently found viruses, accounting for 25.6 and 23.4%, respectively, of the collected samples. BCTV, TSWV, TMV, PVY, ToMV, and TYLCV were detected in 6.1, 5.8, 5.6, 5, 4.8, and 1.6% of the samples, respectively. TBSV, TAV, TSV, PVS, and TRSV were not detected in any of the samples tested. Double and triple infections involving different combination of viruses were found in 13.9 and 1.7% of samples, respectively. This is the first report of PVY and ArMV as viruses naturally infecting tomato in Iran. Infection of tomato plants with PVY and ArMV was confirmed. Six out of 20 plant species belonging to six genera, growing in tomato fields or in the nearby areas, were found infected with TSWV, TMV, PVY, and CMV.

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Outbreak of Tobacco streak virus Causing Necrosis of Cucumber (Cucumis sativus) and Gherkin (Cucumis anguria) in India

Plant Disease ◽

10.1094/pdis.2003.87.10.1264b ◽

2003 ◽

Vol 87 (10) ◽

pp. 1264-1264 ◽

Cited By ~ 18

Author(s):

M. Krishnareddy ◽

Devaraj ◽

Lakshmi Raman ◽

Salil Jalali ◽

D. K. Samuel

Keyword(s):

Electron Microscopy ◽

Sequence Analysis ◽

Mosaic Virus ◽

Cucumis Sativus ◽

Yellow Mosaic Virus ◽

Tobacco Streak Virus ◽

Streak Virus ◽

Natural Occurrence ◽

Thin Sections ◽

Indicator Plants

Cucumber (Cucumis sativus L.) and Gherkin (Cucumis anguria L.) are important cucurbitaceous vegetables grown in India for slicing and pickling. During the 2000 to 2002 rainy season and summer, a new virus disease, causing yield losses of 31 to 75% in Bangalore, Bellary, Davanagiree, and Tumkur districts of Karnataka State, infected cucumber and gherkin. Symptoms were tip necrosis characterized by necrotic lesions on leaves, and a general leaf and stem necrosis extending to mid veins, petioles, flower buds and tip, eventually resulting in dieback of vines. Tissue extracts from symptomatic leaves of cucumber and gherkin were mechanically inoculated on several herbaceous indicator plants (cowpea, cucumber, pepper, Zinnia, watermelon, Chenopodium amaranticolor, sunflower, Nicotiana glutinosa, N. tabacum, and Gomphrena globosa). On most hosts, symptoms of chlorotic or necrotic lesions followed by mottle or systemic necrosis were observed. Back-inoculation from the symptomatic indicator plants onto cucumber and gherkin resulted in symptoms typical of those observed in the field. Electron microscopic examination of leaf-dip preparation and ultra thin sections of virus infected plant samples showed the presence of isometric particles 25 to 28 nm in diameter. Similar types of particles were observed when infected samples were trapped in immunosorbent electron microscopy with polyclonal antibodies specific to Tobacco Streak virus (TSV) but not to Watermelon silver mottle virus (WSMV). Enzymelinked immunosorbent assay tests using leaf extracts of field-collected samples and sap-inoculated plants showed positive reaction to antibodies of TSV (1) but not to antibodies of Cucumber mosaic virus, WSMV, Watermelon bud necrosis virus, Papaya ring spot virus W strain, and Zucchini yellow mosaic virus. Reverse transcription-polymerase chain reaction (RT-PCR) of RNA extracts of infected samples of field and inoculated symptomatic plants was done by using primers derived from TSV RNA3 specific for the coat protein (CP) region of TSV (2). A 800-bp specific DNA fragment was amplified from infected cucumber and gherkin but not from healthy control plants. Sequence analysis of cloned PCR fragments revealed nucleotide identities of 99% with TSV isolates from cotton, mungbean, sunnhemp, and sunflower (GenBank Accessions Nos. AF515824, AF515823, AF515825, and AY061929) and 88% with TSV-WC (GenBank Accession No. X00435). On the basis of host range, serological relationship, electron microscopy, and sequence analysis of the CP region, the virus was identified as a strain of TSV. To our knowledge, this is the first report of natural occurrence of TSV on cucumber and gherkin in India. References: (1). A. I. Bhat et al. Arch. Virol. 147:651, 2002. (2). B. J. C. Cornelissen et al. Nucleic Acids Res.12:2427, 1984.

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Ilarviruses of Prunus spp.: A Continued Concern for Fruit Trees

Phytopathology ◽

10.1094/phyto-02-12-0023-rvw ◽

2012 ◽

Vol 102 (12) ◽

pp. 1108-1120 ◽

Cited By ~ 52

Author(s):

V. Pallas ◽

F. Aparicio ◽

M. C. Herranz ◽

K. Amari ◽

M. A. Sanchez-Pina ◽

...

Keyword(s):

Mosaic Virus ◽

Genome Organization ◽

Alfalfa Mosaic Virus ◽

Fruit Trees ◽

Plant Viruses ◽

International Committee ◽

Economic Losses ◽

Tobacco Streak Virus ◽

Streak Virus ◽

Prunus Spp

Prunus spp. are affected by a large number of viruses, causing significant economic losses through either direct or indirect damage, which results in reduced yield and fruit quality. Among these viruses, members of the genus Ilarvirus (isometric labile ringspot viruses) occupy a significant position due to their distribution worldwide. Although symptoms caused by these types of viruses were reported early in the last century, their molecular characterization was not achieved until the 1990s, much later than for other agronomically relevant viruses. This was mainly due to the characteristic liability of virus particles in tissue extracts. In addition, ilarviruses, together with Alfalfa mosaic virus, are unique among plant viruses in that they require a few molecules of the coat protein in the inoculum in order to be infectious, a phenomenon known as genome activation. Another factor that has made the study of this group of viruses difficult is that infectious clones have been obtained only for the type member of the genus, Tobacco streak virus. Four ilarviruses, Prunus necrotic ringspot virus, Prune dwarf virus, Apple mosaic virus, and American plum line pattern virus, are pathogens of the main cultivated fruit trees. As stated in the 9th Report of the International Committee on Taxonomy of Viruses, virions of this genus are “unpromising subjects for the raising of good antisera.” With the advent of molecular approaches for their detection and characterization, it has been possible to get a more precise view of their prevalence and genome organization. This review updates our knowledge on the incidence, genome organization and expression, genetic diversity, modes of transmission, and diagnosis, as well as control of this peculiar group of viruses affecting fruit trees.

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