First Report of Xylella fastidiosa Infecting Citrus in Costa Rica

Citrus variegated chlorosis (CVC) is an important disease mainly of sweet orange (Citrus sinensis (L.) Osbeck) cultivars. It was first described in Brazil in the state of Sā Paulo in 1987 (4). The disease has spread to all Brazilian states that grow citrus and is affecting more than one-third of the orange trees grown in Brazil. CVC is caused by Xylella fastidiousa, a xylem-limited, gram-negative bacterium. During the last 4 years, symptoms including leaf interveinal chlorosis, stunting, canopy dieback, and hard and undersized fruits, similar to those caused by CVC (3), appeared in sweet orange trees used as shade plants for coffee plantations and as fence posts in Costa Rica. Necrotic lesions on the abaxial side of the leaves as reported in Brazil were rarely observed. Leaf petiole samples from 25 symptomatic sweet orange trees reacted positively with a X fastidiosa-specific antiserum (AGDIA Inc., Elkart, IN) in a double-sandwich antibody enzyme-linked immunosorbent assay (DAS-ELISA). A fastidious, gram-negative bacterium identified as X. fastidiosa using DAS-ELISA was isolated on perwinkle wilt (PW) medium plates (1) from citrus stems showing CVC symptoms, but not from asymptomatic trees. The isolated colonies were circular and opalescent with diameters of 2 to 3 mm and were clearly visible within 6 to 7 days after streaking. Petiole sections from symptomatic plants observed with scanning electron microscopy showed rod-shaped bacteria with rippled cell walls tightly packed in xylem vessels, as described for X. fastidiosa previously (2), and with transmission electron microscopy, the bacteria were morphologically similar to those reported previously for CVC (2). To our knowledge, this is the first report of X. fastidiosa associated with citrus in Costa Rica. References: (1) M. J. Davis et al. Curr. Microbiol. 6:309, 1981. (2) J. S. Hartung et al. Phytopathology 84:591, 1994. (3) R. F. Lee et al. Summa Phytopathol. 19:123, 1993. (4) V. Rossetti et al. 1990, C.R. Acad. Sci. (Paris) 310:345–349.

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First Report of Xylella fastidiosa Associated with Leaf Scorch in Black Oak in Washington, D.C.

Plant Disease ◽

10.1094/pdis.2004.88.2.224c ◽

2004 ◽

Vol 88 (2) ◽

pp. 224-224 ◽

Cited By ~ 2

Author(s):

Q. Huang

Keyword(s):

Xylella Fastidiosa ◽

The United States ◽

Enzyme Linked Immunosorbent Assay ◽

Bacterial Suspension ◽

White Oak ◽

First Report ◽

Leaf Petiole ◽

Leaf Scorch ◽

Pcr Product ◽

Black Oak

Bacterial leaf scorch caused by Xylella fastidiosa has been reported in 17 species of oak including bur, pin, red, scarlet, shingle, and white oaks (3). In September 2002, a leaf scorch symptom characterized by marginal necrosis of leaves bordered by a darker brown band was observed in a mature black oak (Quercus velutina Lam.) at the U.S. National Arboretum in Washington, D.C. The leaf petiole of the black oak was processed in general extraction buffer (Agdia, Inc., Elkhart, IN) contained in a FastDNA lysing matrix tube using the FastPrep FP120 instrument (Qbiogene, Inc., Carlsbad, CA) (1). The leaf petiole extract reacted with an antiserum specific for X. fastidiosa (Agadia, Inc.) in an enzyme-linked immunosorbent assay (ELISA). A slow-growing bacterium was cultured from leaf petioles of the affected black oak tree by soaking the surface-sterilized, finely cut leaf petioles in sterile water for 30 min, followed by spreading the bacterial suspension on periwinkle wilt plates (1). When the cultured bacterium was subjected to polymerase chain reaction (PCR) with primers specific for X. fastidiosa (2), a 472-bp PCR product was detected. The PCR product was confirmed to be the predicted X. fastidiosa product by sequencing and sequence comparison with the reported genomic sequence of X. fastidiosa. ELISA and bacterial isolation from leaf petioles of a nearby symptomless white oak (Q. alba L.) tree were negative. To our knowledge, this is the first report of X. fastidiosa associated with leaf scorch in black oak in the United States, expanding the host range of the bacterium in economically important landscape tree species. References: (1) Q. Huang and J. L. Sherald. Curr. Microbiol. 48:73, 2004. (2) M. R. Pooler and J. S. Hartung. Curr. Microbiol. 31:377, 1995. (3) J. L. Sherald. Xylella fastidiosa, A bacterial pathogen of landscape trees. Page 191 in: Shade Tree Wilt Diseases, C. L. Ash, ed. The American Phytopathological Society, 2001.

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First Report of Cucurbit aphid-borne yellows virus in Iran Causing Yellows on Four Cucurbit Crops

Plant Disease ◽

10.1094/pd-90-0526a ◽

2006 ◽

Vol 90 (4) ◽

pp. 526-526 ◽

Cited By ~ 7

Author(s):

K. Bananej ◽

C. Desbiez ◽

C. Wipf-Scheibel ◽

I. Vahdat ◽

A. Kheyr-Pour ◽

...

Keyword(s):

Citrullus Lanatus ◽

Healthy Plant ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

First Report ◽

Chain Reactions ◽

Reference Isolate ◽

Sigma Chemical ◽

International Mycological Institute ◽

Das Elisa

A survey was conducted from 2001 to 2004 in the major cucurbit-growing areas in Iran to reassess the relative incidence of cucurbit viruses. Severe yellowing symptoms were observed frequently on older leaves of cucurbit plants in various regions in outdoor crops, suggesting the presence of Cucurbit aphid-borne yellows virus (CABYV, genus Polerovirus, family Luteoviridae) (1,2). Leaf samples (n = 1019) were collected from plants of melon (Cucumis melo L.), cucumber (C. sativus L.), squash (Cucurbita sp.), and watermelon (Citrullus lanatus L.) showing various virus-like symptoms (mosaic, leaf deformation, yellowing). All samples, collected from 15 provinces, were screened for the presence of CABYV by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with IgGs and alkaline phosphatase-conjugated IgGs against a CABYV reference isolate (1). Of the 1,019 samples tested, 471 were positive for CABYV using DAS-ELISA. Some of the positive samples had typical severe yellowing symptoms while symptoms in other samples were masked by mosaic or leaf deformations caused by other viruses frequently found in mixed infections (data not shown). During the entire survey, CABYV was detected by DAS-ELISA in 201 of 503 melon samples, 72 of 129 cucumber samples, 158 of 249 squash samples, and 40 of 138 watermelon samples. These results indicate that CABYV is widely distributed on four cucurbit species in the major growing areas of Iran. In order to confirm CABYV identification, total RNA extracts (TRI-Reagent, Sigma Chemical, St Louis, MO) were obtained from 25 samples that were positive using DAS-ELISA originating from Khorasan (n = 4), Esfahan (n = 6), Teheran (n = 3), Hormozgan (n = 4), Azerbaiejan-E-Sharqi (n = 4), and Kerman (n = 4). Reverse transcription-polymerase chain reactions (RT-PCR) were carried out using forward (5′-CGCGTGGTTGTGG-TCAACCC-3′) and reverse (5′-CCYGCAACCGAGGAAGATCC-3′) primers designed in conserved regions of the coat protein gene according to the sequence of a CABYV reference isolate (3) and three other unpublished CABYV sequences. RT-PCR experiments yielded an expected 479-bp product similar to the fragment amplified with extracts from the reference isolate. No amplification of the product occurred from healthy plant extracts. To our knowledge, this is the first report of the occurrence of CABYV in Iran on various cucurbit species. The high frequency (46.2%) with which CABYV was detected in the samples assayed indicates that this virus is one of the most common virus infecting cucurbits in Iran. References: (1) H. Lecoq et al. Plant Pathol. 41:749, 1992 (2) M. A. Mayo and C. J. D'Arcy. Page 15 in: The Luteoviridae. H. G. Smith and H. Barker, eds. CAB International Mycological Institute, Wallingford, UK, 1999. (3) H. Guilley et al. Virology 202:1012, 1994.

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Endotoxin Activity of Moraxella osloensis against the Grey Garden Slug, Deroceras reticulatum

Applied and Environmental Microbiology ◽

10.1128/aem.68.8.3943-3947.2002 ◽

2002 ◽

Vol 68 (8) ◽

pp. 3943-3947 ◽

Cited By ~ 24

Author(s):

Li Tan ◽

Parwinder S. Grewal

Keyword(s):

Biological Control ◽

Parasitic Nematode ◽

Lethal Dose ◽

Bacterial Cells ◽

Negative Bacterium ◽

Deroceras Reticulatum ◽

Gram Negative ◽

First Report ◽

Moraxella Osloensis ◽

Endotoxin Activity

ABSTRACT Moraxella osloensis is a gram-negative bacterium associated with Phasmarhabditis hermaphrodita, a slug-parasitic nematode that has prospects for biological control of mollusk pests, especially the grey garden slug, Deroceras reticulatum. This bacterium-feeding nematode acts as a vector that transports M. osloensis into the shell cavity of the slug, and the bacterium is the killing agent in the nematode-bacterium complex. We discovered that M. osloensis produces an endotoxin(s), which is tolerant to heat and protease treatments and kills the slug after injection into the shell cavity. Washed or broken cells treated with penicillin and streptomycin from 3-day M. osloensis cultures were more pathogenic than similar cells from 2-day M. osloensis cultures. However, heat and protease treatments and 2 days of storage at 22°C increased the endotoxin activity of the young broken cells but not the endotoxin activity of the young washed cells treated with the antibiotics. This suggests that there may be a proteinaceous substance(s) that is structurally associated with the endotoxin(s) and masks its toxicity in the young bacterial cells. Moreover, 2 days of storage of the young washed bacterial cells at 22°C enhanced their endotoxin activity if they were not treated with the antibiotics. Furthermore, purified lipopolysaccharide (LPS) from the 3-day M. osloensis cultures was toxic to slugs, with an estimated 50% lethal dose of 48 μg per slug, thus demonstrating that the LPS of M. osloensis is an endotoxin that is active against D. reticulatum. This appears to be the first report of a biological toxin that is active against mollusks.

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First Report of Sharka Disease Caused by Plum Pox Virus in Lithuania

Plant Disease ◽

10.1094/pdis.1998.82.12.1405c ◽

1998 ◽

Vol 82 (12) ◽

pp. 1405-1405 ◽

Cited By ~ 1

Author(s):

J. Staniulis ◽

J. Stankiene ◽

K. Sasnauskas ◽

A. Dargeviciute

Keyword(s):

Coat Protein ◽

Plant Protection ◽

Virus Disease ◽

Pcr Amplification ◽

Enzyme Linked Immunosorbent Assay ◽

Plum Pox Virus ◽

Rt Pcr ◽

First Report ◽

Das Elisa ◽

Sharka Disease

Plum pox (sharka) disease caused by plum pox potyvirus (PPV) is considered the most important virus disease of stone fruit trees in Europe and the Mediterranean region. Nearly all those countries that produce stone fruits are affected (3). The causal virus of the disease is a European Plant Protection Organization A2 quarantine pathogen. Symptoms of leaf mottling, diffuse chlorotic spots, rings, and vein banding of varied intensity characteristic for plum pox virus infection were observed in the plum (Prunus domestica) orchard tree collection of the Lithuanian Institute of Horticulture in Babtai in 1996. Presence of this virus in the diseased trees was confirmed by double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) with kits from BIOREBA (Reinach, Switzerland) and by polyclonal antibodies raised against a Moldavian isolate of PPV courtesy of T. D. Verderevskaya (Institute of Horticulture, Kishinev, Moldova). ELISAs with both sources of antiserum were positive for presence of PPV. Electron microscopy revealed the presence of potyvirus-like particles averaging 770 nm in extracts of mechanically inoculated plants of Chenopodium foetidum (chlorotic LL [local lesions]) and Pisum sativum cvs. Rainiai and Citron (mottling). For molecular diagnosis and characterization of this isolate, PPV-971, reverse transcription-polymerase chain reaction (RT-PCR) was employed. Total RNA from the leaves of infected pea was isolated as described (2). High molecular weight RNA selectively precipitated with 2 M lithium chloride was used for RT-PCR amplification of the coat protein encoding sequence by use of specific primers complementary to 5′ and 3′ parts of PPV coat protein L1 (GenBank accession no. X81081). Amino acid sequence comparison with GenBank data indicated 98.2% similarity with coat protein of PPV potyvirus isolated by E. Mais et al. (accession no. X81083) and 97.3% with PPV strain Rankovic (1).The specific DNA fragment, corresponding to predicted coat protein sequence size, was cloned into Escherichia coli pUC57 for DNA sequencing. Expression of the cloned sequence in bacteria and yeast expression systems is under investigation. The presence of PPV in plum trees in the 9-year-old collection at Babtai was confirmed by DAS-ELISA in 1997 and again in 1998. PPV was then detected in 20% of symptomatic trees of three cultivars. The Lithuanian PPV isolate reacted positively with “universal” Mab.5b and with a Mab (Mab.4DG5) specific for PPV-D. No reaction was observed with Mabs specific for PPV-M (Mab.AL), PPV-C (Mab.AC and Mab.TUV), and PPV-El Amar (Mab.EA24). PPV-971 seems to be a typical member of the less aggressive Dideron strain cluster of PPV (D. Boscia, personal communication). This is the first report of PPV in Lithuania and confirms the necessity for continuing the precautionary measures established in this country for indexing of nursery plum trees used for graft propagation. References: (1) S. Lain et al. Virus Res. 13:157, 1989. (2) J. Logemann et al. Anal. Biochem. 163:16, 1987. (3) M. Nemeth. OEPP/EPPO Bull. 24:525, 1994.

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First Report of Southern bean mosaic virus Infecting French Bean in Morocco

Plant Disease ◽

10.1094/pdis.2004.88.10.1162b ◽

2004 ◽

Vol 88 (10) ◽

pp. 1162-1162 ◽

Cited By ~ 5

Author(s):

E. Segundo ◽

F. M. Gil-Salas ◽

D. Janssen ◽

G. Martin ◽

I. M. Cuadrado ◽

...

Keyword(s):

Mosaic Virus ◽

Sodium Dodecyl ◽

Plant Viruses ◽

Enzyme Linked Immunosorbent Assay ◽

First Report ◽

Sequence Identity ◽

Southern Bean Mosaic Virus ◽

Bean Plants ◽

Symptomatic Leaf ◽

Das Elisa

Common bean (Phaseolus vulgaris L.) is grown on approximately 1,500 ha in commercial greenhouses and is of major economic importance in the Souss-Massa Region, Agadir, Morocco. Since October 2003, symptoms resembling a viral disease, consisting of pod mosaic and distortion and mild to severe mosaic in leaves, have been observed on bean plants in several greenhouses. Mechanical inoculation with symptomatic leaf extracts produced necrotic local lesions on P. vulgaris ‘Pinto’ and systemic symptoms similar to those observed in the naturally infected bean plants P. vulgaris ‘Donna’ (five plants per cultivar). Inoculated and naturally infected samples reacted positively using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to Southern bean mosaic virus (SBMV) (DSMZ, Braunschweig, Germany), a member of the Sobemovirus genus that is transmitted by contact, soil, beetles, and seeds (1). Virions purified from a naturally infected ‘Donna’ plant contained a 30-kDa polypeptide that reacted positively using sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis with SBMV antiserum (DSMZ). Reverse transcription-polymerase chain reaction amplification with SMBV primers as described by Verhoeven et al. (2) produced an expected 870-bp band. The amplicon was cloned, sequenced (GenBank Accession No. AJ748276), and compared to those isolates available in GenBank and had a nucleotide sequence identity of 87% and a derived amino acid sequence identity of 95% with an SBMV isolate from Spain (2). During a survey in different areas of the Souss-Massa Region, 20 symptomatic leaf and pod samples were randomly collected from 12 greenhouses (50 ha) where significant commercial losses were suffered because of this virus disease, and all samples were positive using DAS-ELISA for SBMV. To our knowledge, this is the first report of SBMV in Morocco. References: (1) J. H. Tremaine and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983. (2) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 109:935, 2003.

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First Report of Citrus tristeza virus in Greece

Plant Disease ◽

10.1094/pdis.2002.86.3.329b ◽

2002 ◽

Vol 86 (3) ◽

pp. 329-329 ◽

Cited By ~ 4

Author(s):

D. Dimou ◽

J. Drossopoulou ◽

E. Moschos ◽

C. Varveri ◽

F. Bem

Keyword(s):

Citrus Tristeza Virus ◽

Sweet Orange ◽

Enzyme Linked Immunosorbent Assay ◽

First Report ◽

Vein Clearing ◽

Carrizo Citrange ◽

Sweet Lime ◽

Tristeza Virus ◽

Propagation Material ◽

Citrus Tristeza

Large-scale surveys of Citrus spp. for the presence of Citrus tristeza virus (CTV) by the Ministry of Agriculture in Greece began in 1995. Over 26,000 trees have been tested by enzyme-linked immunosorbent assay and immunoprinting (2). In summer 2000, the first CTV-infected sweet orange cv. Lane Late tree grafted on CTV-tolerant Carrizo citrange was found in Argolis County, Peloponnese. This tree belonged to a batch of CAC propagation material (20 trees) illegally introduced from Spain in 1994, which was subsequently traced and found to be infected (45%). A follow-up search of trees grafted with the above material was undertaken in the two concerned regions (Argolis and Chania-Crete), and more than 3,500 trees have been removed. Extensive surveys continue to identify and destroy new infections. Few cases (15 of 16,800) of natural transmission to cultivars other than cv. Lane Late have been found. All of these have been close to the initially infected trees in the Argolis area. Surveys in spring 2001 were extended to certified propagation material of Clemenpons mandarin on Carrizo citrange imported from Spain, and 7 of 1,038 plants were infected (0.64%). The virus was successfully graft-transmitted to sweet orange cv. Madame Vinous and sweet lime seedlings, where it was identified by immunoprinting and reverse transcription-polymerase chain reaction (1). Mild vein clearing symptoms appeared on both indicators. Vein clearing on sweet lime was also accompanied by leaf cupping. To our knowledge, this is the first report of CTV in Greece. References: (1) A. Sambade et al. J. Virol. Methods 87:25, 2000. (2) C. Vela et al. J. Gen. Virol. 67:91, 1986.

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First Report of Bean pod mottle virus in Soybean in Iran

Plant Disease ◽

10.1094/pd-89-0775c ◽

2005 ◽

Vol 89 (7) ◽

pp. 775-775 ◽

Cited By ~ 4

Author(s):

N. Shahraeen ◽

T. Ghotbi ◽

M. Salati ◽

A. Sahandi

Keyword(s):

Visual Assessment ◽

Leaf Beetle ◽

Mottle Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Minor Importance ◽

Bean Pod Mottle Virus ◽

Trifoliate Leaf ◽

First Report ◽

Das Elisa ◽

Green Stem

Soybean (Glycine max (L.) Merr.) has been increasing in importance and acreage for the past 5 years in Iran and is now planted on approximately 108,000 ha. Previous surveys in Iran of viruses infecting soybean failed to identify Bean pod mottle virus (BPMV), but the incidence of other common viruses of soybean in the field has been reported (1). During October 2004, symptoms characteristic of those caused by BPMV including mosaic, puckering of trifoliate leaves, and delayed maturity of stems or green stems were observed in soybean fields in the Takhti Mahaleh, Versen, and Hashemabad areas located in the Gorgan Province. Sporadic incidence of plants infected with BPMV has been usually of minor importance to growers. Symptoms were often overlooked or considered to be physiological disorders. A visual assessment was made to determine incidence of green stem in the commonly grown soybean cv. Sahar. Forty soybean plants showing symptoms of crinkling, mottling, green stem, and retaining green leaves were sampled by collecting one trifoliate leaf near the top of the plant. All samples were tested in parallel for BPMV using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). BPMV was detected in 40% of the samples. Seven of the samples shown to be infected with BPMV using DAS-ELISA were mechanically (2) transferred to soybean seedlings in the greenhouse. These plants developed systemic mottle symptoms typical of those caused by BPMV and tested positive for BPMV using DAS-ELISA. The distribution of BPMV within soybean-growing regions, exploration of potential virus reservoirs, and economic impact of this virus have yet to be determined. There is no published report on the presence of potential BPMV vectors including the bean leaf beetle (Cerotoma trifurcata) from soybean fields in Iran. To our knowledge, this is the first report of BPMV in Iran. References: (1) A. R. Golnaraghi et al. Plant Dis.88:1069, 2004. (2) R. Louie et al. Plant Dis.84:1133, 2000.

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Pierce's disease bacterium in petiolar xylem of grape leaves

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113275 ◽

1984 ◽

Vol 42 ◽

pp. 678-679

Author(s):

G. E. Tyson ◽

B. J. Stojanovic ◽

R. Kuklinski ◽

T. DiVittorio ◽

M. Sullivan

Keyword(s):

Electron Microscopy ◽

Old French ◽

Pierce's Disease ◽

Negative Bacterium ◽

Gram Negative ◽

Bacterial Surface ◽

Pierce’S Disease ◽

Transmission Electron ◽

Bacterial Aggregates ◽

Hybrid Cultivar

Pierce's disease (PD) of grapevines is caused by a rod-shaped, gram-negative bacterium that is transmitted by xylem-feeding suctorial insects. Petioles from a grapevine (four-year old French-American hybrid, cultivar DeChaunac) with overt symptoms typical of PD were examined by conventional scanning and transmission electron microscopy in order to describe the external morphology of intraxylar bacterial aggregates and to verify the presence of features known from previous studies to be characteristic of PD bacteria. These features included the size and rod-shape of the bacterium (1.0-2.2 μm long, 0.39-0.53 μm wide), the ridged nature of the bacterial surface (Fig. 1), the membrane-like ultrastructure of the cell wall typical of gram-negative cells, and the xylem-limited occurrence within the host plant.

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Dicentra, Epimedium, and Heuchera: New Perennial Ornamental Hosts of Tobacco rattle virus in the United States

Plant Disease ◽

10.1094/pdis.2000.84.12.1344a ◽

2000 ◽

Vol 84 (12) ◽

pp. 1344-1344 ◽

Cited By ~ 7

Author(s):

B. E. L. Lockhart

Keyword(s):

Electron Microscopy ◽

United States ◽

Tobacco Rattle Virus ◽

Leaf Tissue ◽

Particle Morphology ◽

The United States ◽

Enzyme Linked Immunosorbent Assay ◽

Infected Leaf ◽

Natural Occurrence ◽

First Report

Yellow ringspotting and concentric line patterns in plants of Dicentra (bleeding heart), Epimedium (barrenwort), and Heuchera (coral bells) from commercial nurseries and home gardens in Minnesota, Michigan, and Massachusetts were associated with infection by Tobacco rattle virus (TRV), which was identified by particle morphology, enzyme-linked immunosorbent assay and immunosorbent electron microscopy. No other viruslike particles were observed by electron microscopy in partially purified preparations of TRV-infected leaf tissue, and TRV was not detected in asymptomatic plants. This is the first report of TRV occurrence in Dicentra in the United States and the first report of TRV occurrence in Epimedium and Heuchera. In previous reports (1,2) we have called attention to the increasing incidence of TRV in vegetatively propagated perennial ornamental plant species in the United States and to the potential for virus spread to crops such as potato, in which TRV has not been reported in the midwestern United States. It is possible that increased international trade in vegetatively propagated ornamental plants may be resulting in the introduction of TRV and other exotic viruses into the United States and elsewhere. It is also possible that the natural occurrence of TRV in North America may be actually more widespread than has been reported. References: (1) B. E. Lockhart et al. Plant Dis. 79:1249, 1995. (2) B. E. Lockhart and J. A. Westendorp. Plant Dis. 82:712, 1998.

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First Report of Raspberry bushy dwarf virus on Red Raspberry and Grapevine in Slovenia

Plant Disease ◽

10.1094/pdis.2003.87.9.1148d ◽

2003 ◽

Vol 87 (9) ◽

pp. 1148-1148 ◽

Cited By ~ 12

Author(s):

I. Mavrič ◽

M. Viršček Marn ◽

D. Koron ◽

I. Žežlina

Keyword(s):

Polyclonal Antiserum ◽

Rubus Idaeus ◽

Dwarf Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Natural Occurrence ◽

Red Raspberry ◽

Rt Pcr ◽

First Report ◽

Raspberry Bushy Dwarf Virus ◽

Das Elisa

In 2002, severe vein yellowing and partial or complete yellowing of leaves was observed on some shoots of red raspberry (Rubus idaeus) cvs. Golden Bliss and Autumn Bliss. Sap of infected plants of cv. Golden Bliss was inoculated onto Chenopodium quinoa and Nicotiana benthamiana. Faint chlorotic spots were observed on inoculated leaves of C. quinoa approximately 14 days after inoculation but no systemic symptoms appeared. No symptoms were observed on N. benthamiana. Raspberry bushy dwarf virus (RBDV) was detected in the original raspberry plant using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with polyclonal antiserum (Loewe Biochemica, Sauerlach, Germany). Systemic infections of inoculated C. quinoa and N. benthaminana were confirmed using DAS-ELISA. In 2001 and 2002, unusual virus symptoms were observed on grapevine grafts (Vitis vinifera) of cv. Laški Rizling. Symptoms appeared as curved line patterns and yellowing of the leaves. No nepoviruses were found in symptomatic plants, but RBDV was confirmed using DAS-ELISA. RBDV infection was later confirmed in grapevine cv. Štajerska Belina with similar symptoms. RBDV was transmitted mechanically from grapevine to C. quinoa where it was detected by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR). IC-RT-PCR was used to amplify a part of the coat protein gene of the virus from raspberry and grapevine, and the amplification products were sequenced (1). The obtained sequence shared at least 93% nucleotide sequence identity with other known RBDV sequences, which confirmed the serological results. To our knowledge, this is the first report of the natural occurrence of RBDV in grapevine and also of RBDV infection of red raspberry in Slovenia. Reference: (1) H. I. Kokko et al. Biotechniques 20:842, 1996.

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