First Ocurrence of a Rhabdovirus Infecting Maize in Argentina

Maize (Zea mays) plants showing symptoms of shortened internodes, dwarfism, panicle sterility, and a mosaic of coarse and fine yellow stripes on leaf blades and sheaths, were found from December to March in experimental maize plantings in every crop year since 2000-01. Although the disease appeared at a very low incidence (estimates less than 1%), it was found in several locations such as Santa Isabel and Venado Tuerto, Santa Fe Province; Río Cuarto, Colonia Caroya, Río Segundo, and Sampacho, Córdoba Province; and Pedro Luro, Buenos Aires Province. Leaf tissue from eight symptomatic plants collected in Colonia Caroya in December 2011 was used to perform “leaf dips” and ultrathin sections. Electron microscopy of these preparations revealed membrane-bound bullet-shaped particles characteristic of the Rhabdoviridae family in mesophyll cytoplasm and vascular bundle parenchyma. The virus was experimentally transmitted to healthy 9-day-old corn plants, with Peregrinus maidis (order Hemiptera, family Delphacidae) raised under laboratory conditions using acquisition, latency, and inoculation vector periods of 7, 21, and 7 days, respectively. The field observed symptoms were replicated in the transmitted plants. Total RNA was extracted from symptomatic and asymptomatic plants with the RNeasy Plant Mini Kit (Qiagen, Germany), and one step RT-PCR (Access RT-PCR Kit, Promega, Madison, WI) was performed, using two sets of degenerate primers targeting conserved regions of rhabdovirus L polymerase gene, primers PVO (1) and Rhab (2). The agarose gel bands shown only in symptomatic samples were 450 bp (1) and 1,000 bp (2), as expected. The approximately 1 kb amplicon, which includes that of 450 bp, was cloned into pGEM-T Easy Vector System (Promega). Five independent clones were sequenced in both directions with M13 F/R universal primers to generate a consensus sequence (GenBank Accession No. JQ715419), which was compared to similar plant rhabdovirus sequences available on GenBank. The partial L polymerase gene sequence of the corn rhabdovirus, Maize yellow striate virus had 73% and 71% sequence identity with the members of the Cytorhabdovirus genus Barley yellow striate mosaic virus isolate Zanjan-1 (BYSMV; GenBank Accession No. FJ665628) and Northern cereal mosaic virus (NCMV; GenBank Accession No. NC002251), respectively. A phylogenetic tree from the partial nucleotide L polymerase sequence indicates that the rhabdovirus infecting maize in Argentina is closely related to the cytorhabdovirus members and is separated from the nucleorhabdovirus group. To our knowledge, this is the first mention of a Rhabdoviridae family virus infecting maize detected in Argentina. References: (1) H. Bourhy et al. J. Gen. Virol. 86:2849, 2005. (2) R. L. Lamprecht et al. Eur. J. Plant Pathol. 123:105, 2009.

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First Report of Lettuce big-vein associated virus (Varicosavirus) Infecting Lettuce in Mexico

Plant Disease ◽

10.1094/pdis-07-13-0761-pdn ◽

2014 ◽

Vol 98 (4) ◽

pp. 573-573 ◽

Cited By ~ 3

Author(s):

D. L. Ochoa-Martínez ◽

J. Alfonsina-Hernández ◽

J. Sánchez-Escudero ◽

D. Rodríguez-Martínez ◽

J. Vera-Graziano

Keyword(s):

Mosaic Virus ◽

Consensus Sequence ◽

Leaf Tissue ◽

Plant Viruses ◽

Australian Isolate ◽

Healthy Plant ◽

Rt Pcr ◽

First Report ◽

Chlorotic Spot ◽

Spanish Isolate

Lettuce (Lactuca sativa) is a common consumed vegetable and a major source of income and nutrition for small farmers in Mexico. This crop is infected with at least nine viruses: Mirafiori lettuce big-vein virus (MiLBVV), Lettuce big-vein associated virus (LBVaV), both transmitted by the soil-borne fungus Olpidium brassicae; Tomato spotted wilt virus (TSWV), Tomato chlorotic spot virus (TCSV), Groundnut ringspot virus (GRSV), Lettuce mottle virus (LMoV), Cucumber mosaic virus (CMV), Bidens mosaic virus (BiMV), and Lettuce mosaic virus (LMV) (1). From March to May 2012, a disease on lettuce was observed in the south region of Mexico City displaying mild to severe mosaic, leaf deformation, reduced growth, slight thickening of the main vein, and plant death. At the beginning of the epidemic there were just a few plants with visible symptoms and 7 days later the entire crop was affected, causing a loss of 93% of the plants. It was estimated by counting the number of severely affected or dead plants in three plots. No thrips, aphids, or whiteflies were observed in the crop during this time. Twenty plants with similar symptoms were collected and tested by RT-PCR using the primers LBVaVF 5′-AACACTATGGGCATCCACAT-3′ and LBVaVR 5′-GCATGTCAGCAATCAGAGGA-3′ specific for the coat protein gene of LBVaV, amplifying a 322-bp fragment. Primers CP829F 5′-CCWACTTCATCAGTTGAGCGCTG-3′ and CP1418R 5′-TATCAGCTCCCTACACTATCCTCGC-3′ were used to detect MiLBVV (2). No amplification was obtained for MiLBVaV in any plants tested. PCR products of approximately 300 bp were obtained from four out of 20 symptomatic lettuce samples tested for LBVaV, but not from healthy plant and water controls. These results suggest the presence of another virus in symptomatic lettuce plants. Amplicons were gel-purified and sequenced using LBVaVF and LBVaVR primers. A consensus sequence was generated using the Bioedit v. 5 program. Both sequences of these Mexican lettuce isolates were 100% identical (Accession Nos. KC776266.1 and KC776267.1) and had identities between 94 and 99% to all sequences of LBVaV available in GenBank. Additionally, when alignments were made using ClustalW, these sequences showed identities of 99.7% to Almeria-Spanish isolate (Accession No. AY581686.1); 99.4% to Granada-Spanish isolate (AY581689.1); 99.1% to Dutch isolate (JN710441.1), Iranian isolate (JN400921.1), Australian isolate (GU220725.1), Brazilian isolate (DQ530354.1), England isolate (AY581690.1), and American isolate (AY496053.1); 96.2% to Australian isolate (GU220722.1); 96.3% to Japanese isolate (AB190527.1); and 92.8% to Murcia-Spanish isolate (AY581691.1). Twenty lettuce plants were mechanically inoculated with leaf tissue taken from the four plants collected in the field and tested positive for LBVaV by RT-PCR; 12 days after inoculation, mosaic symptoms were observed in all inoculated plants and six of them were analyzed individually by RT-PCR obtaining a fragment of the expected size. To our knowledge, this is the first report of LBVaV infecting lettuce in Mexico. Further surveys and monitoring of LBVaV incidence and distribution in the region, vector competence of olpidium species, and impact on the crop quality are in progress. References: (1) P. M. Agenor et al. Plant Viruses 2:35, 2008. (2) R. J. Hayes et al. Plant Dis. 90:233, 2006.

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First Report of Catharanthus mosaic virus in Mandevilla in the United States

Plant Disease ◽

10.1094/pdis-09-14-0913-pdn ◽

2015 ◽

Vol 99 (1) ◽

pp. 165-165 ◽

Cited By ~ 4

Author(s):

D. Mollov ◽

M. A. Guaragna ◽

B. Lockhart ◽

J. A. M. Rezende ◽

R. Jordan

Keyword(s):

United States ◽

Amino Acid ◽

Mosaic Virus ◽

Consensus Sequence ◽

The United States ◽

Amino Acid Sequences ◽

Universal Primers ◽

Rt Pcr ◽

First Report ◽

Virus Particles

Mandevilla (Apocynaceae) is an ornamental tropical vine popular for its bright and attractive flowers. During 2012 to 2013, 12 Mandevilla sp. samples from Minnesota and Florida nurseries were submitted for analysis at the University of Minnesota Plant Disease Clinic. Plants showed mosaic symptoms, leaf deformation, premature leaf senescence, and vine dieback. Filamentous virus particles with modal lengths 700 to 900 nm were observed by transmission electron microscopy (TEM) in partially purified preparations from symptomatic leaves. Partially purified virions were obtained using 30% sucrose cushion centrifuged at 109,000 gmax for 2 h at 10°C (5). No other virus particles were observed in these samples, nor were any observed in non-symptomatic samples. One sample was submitted as potted plant (Mandevilla ‘Sunmandeho’ Sun Parasol Giant White) and was kept under greenhouse conditions for subsequent analyses. Total RNA (Qiagen) was extracted from this sample, and Potyvirus was detected using the universal primers Poty S (5′-GGN AAY AAY AGY GGN CAR CC-3′) and PV1 (5′-20(T)V-3′) (1) by reverse transcription (RT)-PCR (3). The amplified product was the expected ~1.7-kb, corresponding to the partial nuclear inclusion body gene, the coat protein (CP) gene, and the 3′ end untranslated region. The RT-PCR amplicon was cloned (NEB) and sequenced, and the 1,720-bp consensus sequence was deposited in GenBank (Accession No. KM243928). NCBI BLAST analysis at the nucleotide level revealed highest identity (83%) with an isolate of Catharanthus mosaic virus (CatMV) from Brazil (Accession No. DQ365928). Pairwise analysis of the predicted 256 amino acid CP revealed 91% identity with the CatMV Brazilian isolate (ABI94824) and 68% or less identity with other potyviruses. Two potyviruses are usually considered the same species if their CP amino acid sequences are greater than 80% identical (2). Serological analysis of the infected sample Mandevilla ‘Sunmandeho’ Sun Parasol Giant White using a CatMV specific antiserum (4) resulted in positive indirect ELISA reactions. CatMV has been previously reported in periwinkle (Catharanthus roseus) in Brazil (4). Based on the analyses by TEM, RT-PCR, nucleotide and amino acid sequence identities, and serological reactivity, we identify this virus as a U.S. Mandevilla isolate of CatMV. To our knowledge, this is the first report of Catharanthus mosaic virus both in the United States and in Mandevilla. References: (1) J. Chen et al. Arch Virol. 146:757, 2001. (2) A. Gibbs and K. Ohshima. Ann. Rev. Phytopathol. 48:205, 2010. (3) R. L. Jordan et al. Acta Hortic. 901:159, 2011. (4) S. C. Maciell et al. Sci. Agric. Piracicaba, Brazil. 68:687, 2011. (5) D. Mollov et al. Arch Virol. 158:1917, 2013.

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First Report of a Rhabdovirus Infecting Alfalfa in Argentina

Plant Disease ◽

10.1094/pdis-10-10-0764 ◽

2011 ◽

Vol 95 (6) ◽

pp. 771-771 ◽

Cited By ~ 18

Author(s):

N. Bejerman ◽

C. Nome ◽

F. Giolitti ◽

E. Kitajima ◽

S. de Breuil ◽

...

Keyword(s):

Amino Acid ◽

Consensus Sequence ◽

Amino Acid Sequences ◽

Vector System ◽

Rt Pcr ◽

Degenerate Primers ◽

Production Chain ◽

First Report ◽

Pcr Assays ◽

Plant Rhabdovirus

Alfalfa (Medicago sativa L.) is a major forage crop in Argentina with an estimated cultivated area of 4 million ha in the 2009–2010 season, which constitutes a primary component for the animal production chain. In early summer of 2010, alfalfa plants showing virus-like symptoms were identified in 20 commercial fields in La Pampa Province with 95% disease prevalence. Diseased plants had shortened internodes, a bushy appearance, deformations, puckering, epinasty of leaflet blades, vein enations, and varying sized papillae on the adaxial leaflet surfaces. Similar symptoms were observed in alfalfa crops in Buenos Aires, Cordoba, Santa Fe, and Santiago del Estero provinces. Electron microscopy (EM) and molecular assays were performed on leaf tissue from one asymptomatic and two symptomatic plants. EM of ultrathin sections revealed membrane-bound bullet-shaped particles associated with the endoplasmic reticulum of phloem cells from symptomatic plants only. Total RNA was extracted from symptomatic and asymptomatic plants with the RNeasy Plant Mini Kit (Qiagen, Hilden, Germany) for a template in one-step reverse transcription (RT)-PCR assays with the Access RT-PCR Kit (Promega, Madison, WI). RT-PCR assays employed degenerate primers targeting conserved regions of plant rhabdovirus polymerase (L) genes (2). An amplicon of approximately 1 kilobase pairs (detected only from symptomatic plants) was gel purified with the Wizard SV Gel and PCR Clean-Up System (Promega), cloned into pGEM-T Easy Vector System (Promega), and sequenced. Three independents clones were sequenced in both directions at Macrogen Inc. (Korea Republic) to generate a consensus sequence (GenBank Accession No. HQ380230) and compared to sequences of other plant rhabdoviruses available on GenBank. The partial L gene sequence of the alfalfa-infecting rhabdovirus shared highest nucleotide (68.0%) and amino acid (76.5%) sequence identity with the cytorhabdovirus Strawberry crinkle virus (Accession No. AY331390). A phylogenetic tree based on partial amino acid sequences of the polymerase gene indicated the alfalfa-infecting virus was more closely related to cytorhabdoviruses than to nucleorhabdoviruses. Symptoms observed resembled those reported for alfalfa plants infected with a plant rhabdovirus named Alfalfa enation virus (1), which has never been fully characterized. Collectively, the data implicate the observed rhabdovirus as the etiological agent. To our knowledge, this is the first report in Argentina (and South America) of a rhabdovirus infecting alfalfa. Additional field surveys and monitoring of vector/s and yield losses need to be conducted. References: (1) B. Alliot and P. A. Signoret. Phytopathol. Z. 74:69, 1972. (2) R. L. Lamprecht et al. Eur. J. Plant Pathol. 123:105, 2009.

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First report of Coleus blumei viroid 1 in commercial Coleus blumei in the United States

Plant Disease ◽

10.1094/pdis-05-21-0917-pdn ◽

2021 ◽

Author(s):

Gardenia Orellana ◽

Alexander V Karasev

Keyword(s):

United States ◽

Leaf Tissue ◽

The United States ◽

Universal Primers ◽

Rt Pcr ◽

Universal Primer ◽

Tissue Samples ◽

First Report ◽

Specific Pcr ◽

Coleus Blumei

Coleus scutellarioides (syn. Coleus blumei) is a widely grown evergreen ornamental plant valued for its highly decorative variegated leaves. Six viroids, named Coleus blumei viroid 1 to 6 (CbVd-1 to -6) have been identified in coleus plants in many countries of the world (Nie and Singh 2017), including Canada (Smith et al. 2018). However there have been no reports of Coleus blumei viroids occurring in the U.S.A. (Nie and Singh 2017). In April 2021, leaf tissue samples from 27 cultivars of C. blumei, one plant of each, were submitted to the University of Idaho laboratory from a commercial nursery located in Oregon to screen for the presence of viroids. The sampled plants were selected randomly and no symptoms were apparent in any of the samples. Total nucleic acids were extracted from each sample (Dellaporta et al. 1983) and used in reverse-transcription (RT)-PCR tests (Jiang et al. 2011) for the CbVd-1 and CbVd-5 with the universal primer pair CbVds-P1/P2, which amplifies the complete genome of all members in the genus Coleviroid (Jiang et al. 2011), and two additional primer pairs, CbVd1-F1/R1 and CbVd5-F1/R1, specific for CbVd-1 and CbVd-5, respectively (Smith et al. 2018). Five C. blumei plants (cvs Fire Mountain, Lovebird, Smokey Rose, Marrakesh, and Nutmeg) were positive for a coleviroid based on the observation of the single 250-nt band in the RT-PCR test with CbVds-P1/P2 primers. Two of these CbVd-1 positive plants (cvs Lovebird and Nutmeg) were also positive for CbVd-1 based on the presence of a single 150-nt band in the RT-PCR assay with CbVd1-F1/R1 primers. One plant (cv Jigsaw) was positive for CbVd-1, i.e. showing the 150-nt band in RT-PCR with CbVd1-F1/R1 primers, but did not show the ca. 250-bp band in RT-PCR with primers CbVds-P1/P2. None of the tested plants were positive for CbVd-5, either with the specific, or universal primers. All coleviroid- and CbVd-1-specific PCR products were sequenced directly using the Sanger methodology, and revealed whole genomes for five isolates of CbVd-1 from Oregon, U.S.A. The genomes of the five CbVd-1 isolates displayed 96.9-100% identity among each other and 96.0-100% identity to the CbVd-1 sequences available in GenBank. Because the sequences from cvs Lovebird, Marrakesh, and Nutmeg, were found 100% identical, one sequence was deposited in GenBank (MZ326145). Two other sequences, from cvs Fire Mountain and Smokey Rose, were deposited in the GenBank under accession numbers MZ326144 and MZ326146, respectively. To the best of our knowledge, this is the first report of CbVd-1 in the United States.

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First Report of Yam mild mosaic virus in Yam in Guangxi Province, China

Plant Disease ◽

10.1094/pdis-04-11-0350 ◽

2011 ◽

Vol 95 (10) ◽

pp. 1320-1320 ◽

Cited By ~ 4

Author(s):

C. Zou ◽

J. Meng ◽

Z. Li ◽

M. Wei ◽

J. Song ◽

...

Keyword(s):

Mosaic Virus ◽

Viral Genome ◽

Terminal Region ◽

Mild Mosaic ◽

Rt Pcr ◽

Degenerate Primers ◽

Germplasm Exchange ◽

First Report ◽

Pcr Products ◽

Mild Mosaic Virus

Yams (Dioscorea spp.) are widely grown in China as vegetables and herbal medicine. However, studies on viral diseases on yams are still limited. As a pilot project of a government initiative for improving yam productivity, a small study was conducted in Guangxi, a southern province of China, on viral disease in yams. Incidence of virus-like disease for the three extensively grown D. alata cultivars, GH2, GH5, and GH6, were 12 to 40%, 12 to 29%, and 11 to 25%, respectively, as found in a field survey with a five-plot sampling method in 2010. A total of 112 leaf samples showing mosaic or mottling or leaves without symptoms were collected from the cvs. GH2, GH5, GH6, and seven additional cultivars (D. alata cvs. GY2, GY23, GY47, GY69, GY62, GY72, and D. batatas cv. Tiegun). To determine if the symptoms were caused by Yam mild mosaic virus (YMMV; genus Potyvirus, family Potyviridae), total RNA was extracted from leaves with a commercial RNA purification kit (TIANGEN, Beijing, China), and reverse-transcription (RT)-PCR was conducted with a YMMV-specific primer pair (4) that amplifies the 3′-terminal portion of the viral genome. A PCR product with the predicted size of 262 bp was obtained from samples of GH5 (number testing positive of total number of leaves = 5 of 12), GH6 (24 of 42), and GY72 (1 of 1), but not from asymptomatic leaves. PCR products from a GH5 sample (YMMV-Nanning) and a GH6 sample (YMMV-Luzhai) were cloned and sequenced using an ABI PRISM 3770 DNA Sequencer. The two PCR products were 97% identical at nucleotide (nt) level and with the highest homology (89% identity) to a YMMV isolate (GenBank Accession No. AJ305466). To further characterize the isolates, degenerate primers (2) were used to amplify viral genome sequence corresponding to the C-terminal region of the nuclear inclusion protein b (NIb) and the N-terminal region of the coat protein (CP). These 781-nt fragments were sequenced and a new primer, YMMV For1 (5′-TTCATGTCGCACAAAGCAGTTAAG-3′) corresponding to the NIb region, was designed and used together with primer YMMV UTR 1R to amplify a fragment that covers the complete CP region of YMMV by RT-PCR. These 1,278-nt fragments were sequenced (GenBank Accession Nos. JF357962 and JF357963). CP nucleotide sequences of the YMMV-Nanning and YMMV-Luzhai isolates were 94% similar, while amino acid sequences were 99% similar. BLAST searches revealed a nucleotide identity of 82 to 89% and a similarity of 88 to 97% for amino acids to sequences of YMMV isolates (AF548499 and AF548519 and AAQ12304 and BAA82070, respectively) in GenBank. YMMV is known to be prevalent on D. alata in Africa and the South Pacific, and has recently been identified in the Caribbean (1) and Colombia (3). To our knowledge, this is the first report of the natural occurrence of YMMV in China and it may have implications for yam production and germplasm exchange within China. References: (1) M. Bousalem and S. Dallot. Plant Dis. 84:200, 2000. (2) D. Colinet et al. Phytopathology 84:65, 1994. (3) S. Dallot et al. Plant Dis. 85:803, 2001. (4) R. A. Mumford and S. E. Seal. J. Virol. Methods 69:73, 1997.

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Tropical soda apple mosaic virus Identified in Solanum capsicoides in Florida

Plant Disease ◽

10.1094/pdis-91-9-1204a ◽

2007 ◽

Vol 91 (9) ◽

pp. 1204-1204 ◽

Cited By ~ 2

Author(s):

S. Adkins ◽

G. McAvoy ◽

E. N. Rosskopf

Keyword(s):

Sequence Analysis ◽

Mosaic Virus ◽

Sandwich Elisa ◽

Tomato Mosaic Virus ◽

Rt Pcr ◽

Degenerate Primers ◽

Lee County ◽

Cp Gene ◽

Local Lesions ◽

Tropical Soda Apple

Red soda apple (Solanum capsicoides All.), a member of the Solanaceae, is a weed originally from Brazil (3). It is a perennial in southern Florida and is characterized by abundant prickles on stems, petioles, and leaves. Prickles on stems are more dense than those on its larger, noxious weed relative, tropical soda apple (Solanum viarum Dunal), and the mature red soda apple fruits are bright red in contrast to the yellow fruits of tropical soda apple (2). Virus-like foliar symptoms of light and dark green mosaic were observed on the leaves of a red soda apple in a Lee County cow pasture during a tropical soda apple survey during the fall of 2004. The appearance of necrotic local lesions following inoculation of Nicotiana tabacum cv. Xanthi nc with sap from the symptomatic red soda apple leaves suggested the presence of a tobamovirus. Tropical soda apple mosaic virus (TSAMV), a recently described tobamovirus isolated from tropical soda apple in Florida, was specifically identified by a double-antibody sandwich-ELISA (1). An additional six similarly symptomatic red soda apple plants were later collected in the Devils Garden area of Hendry County. Inoculation of N. tabacum cv. Xanthi nc with sap from each of these symptomatic plants also resulted in necrotic local lesions. Sequence analysis of the TSAMV coat protein (CP) gene amplified from total RNA by reverse transcription (RT)-PCR with a mixture of upstream (SolA5′CPv = 5′-GAACTTWCAGAAGMAGTYGTTGATGAGTT-3′; SolB5′CPv = 5′-GAACTCACTGARRMRGTTGTTGAKGAGTT-3′) and downstream (SolA3′CPvc = 5′-CCCTTCGATTTAAGTGGAGGGAAAAAC-3′; SolB3′CPvc = 5′-CGTTTMKATTYAAGTGGASGRAHAAMCACT-3′) degenerate primers flanking the CP gene of Solanaceae-infecting tobamoviruses confirmed the presence of TSAMV in all plants from both locations. Nucleotide and deduced amino acid sequences of the 483-bp CP gene were both 98 to 99% identical to the original TSAMV CP gene sequences in GenBank (Accession No. AY956381). TSAMV was previously identified in tropical soda apple in these two locations in Lee and Hendry counties and three other areas in Florida (1). Sequence analysis of the RT-PCR products also revealed the presence of Tomato mosaic virus in the plant from Lee County. To our knowledge, this represents the first report of natural TSAMV infection of any host other than tropical soda apple and suggests that TSAMV may be more widely distributed in solanaceous weeds than initially reported. References: (1) S. Adkins et al. Plant Dis. 91:287, 2007. (2) N. Coile. Fla. Dep. Agric. Consum. Serv. Div. Plant Ind. Bot. Circ. 27, 1993. (3) U.S. Dep. Agric., NRCS. The PLANTS Database. National Plant Data Center. Baton Rouge, LA. Published online, 2006.

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Universal primers for rapid detection of six pospiviroids in Solanaceae plants using one-step RT-PCR and RT-LAMP

Plant Disease ◽

10.1094/pdis-12-20-2730-re ◽

2021 ◽

Author(s):

Yi-Wen Tseng ◽

Chien-Fu Wu ◽

Chia-Hwa Lee ◽

Chung Jan Chang ◽

Yuh-Kun Chen ◽

...

Keyword(s):

Potato Spindle Tuber Viroid ◽

Detection Methods ◽

Universal Primers ◽

Rt Pcr ◽

Degenerate Primers ◽

Highly Sensitive ◽

One Step ◽

Tomato Chlorotic Dwarf Viroid ◽

Minimal Concentration ◽

Solanaceous Plants

A number of viruses and viroids infect solanaceous plants causing severe yield losses. Several seed-borne viroids are currently listed as quarantine pathogens in many countries. Among them, columnea latent viroid (CLVd), pepper chat fruit viroid (PCFVd), potato spindle tuber viroid (PSTVd), tomato apical stunt viroid (TASVd), tomato chlorotic dwarf viroid (TCDVd), and tomato planta macho viroid (TPMVd) are of major concerns. The objective of this study was to design and test universal primers that could be used to detect six viroids in solanaceous plants using one-step RT-PCR and reverse transcription loop-mediated isothermal amplification (RT-LAMP). Results revealed that a pair of degenerate primers could be used in a one-step RT-PCR to amplify six pospiviroids from Solanaceae seeds and plants. Moreover, five primers were designed and used in RT-LAMP to amplify six pospiviroids. The minimal concentration of viroid RNA required for a successful detection varied, ranging from one femtogram to 10 nanograms, depending on the species of viroid and detection method. In general, RT-LAMP was more sensitive than RT-PCR but both assays were rapid and highly sensitive tools to detect six pospiviroids. Detection methods currently in use for these viroids require at least two different sets of primers. The assays developed in this research could facilitate to screen a large number of solanaceous plants and seeds intended for import and export.

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First Report of Apium virus Y on Cilantro, Celery, and Parsley in California

Plant Disease ◽

10.1094/pdis-92-8-1254b ◽

2008 ◽

Vol 92 (8) ◽

pp. 1254-1254 ◽

Cited By ~ 7

Author(s):

T. Tian ◽

H.-Y. Liu ◽

S. T. Koike

Keyword(s):

Mosaic Virus ◽

Consensus Sequence ◽

Amino Acid Sequences ◽

Apium Graveolens ◽

Petroselinum Crispum ◽

Rt Pcr ◽

First Report ◽

Virus Particles ◽

Pcr Products ◽

Reverse Primer

Recently, Apium virus Y (ApVY) was detected in field-grown cilantro (Coriandrum sativum), celery (Apium graveolens), and parsley (Petroselinum crispum) in California. In 2003, cilantro plants growing in three different fields in California (Monterey, San Joaquin, and San Luis Obispo counties) expressed symptoms of mosaic, vein clearing, and stunting. When plant sap was examined by transmission electron microscopy, flexuous, rod-shaped virus particles were observed. Total RNA was extracted from the symptomatic cilantro plants and used as a template in reverse transcription (RT)-PCR using universal potyvirus primers according to Chen et al. (1). The RT-PCR product was cloned into pGEM-T (Promega, Madison, WI) and the insert of 1,713 bp was sequenced (GenBank Accession No. EU515125). Nucleotide sequences from clones derived from three different infected cilantro plants were 89 to 97% identical to ApVY sequences encoding partial sequence of polyprotein in GenBank (Accession Nos. AY049716, EU127499, AF207594, AF203529, and EU255632). In 2007, celery plants showing necrotic line patterns and necrotic lesions on lower leaves and petioles were observed in several fields in two coastal counties in California (Monterey and Santa Clara counties). Flexuous, rod-shaped virus particles were also observed in the sap of those plants. ELISA for Cucumber mosaic virus and RT-PCR for Celery mosaic virus were negative. ApVY specific primers were designed on the basis of a consensus sequence of ApVY identified from cilantro in 2003; reverse primer 5′-GGCTCTTGCTATAGACAAATAGT-3′ and forward primer 5′-GAAGACCAAGCCAATGTGTGTA-3′. The sequence of RT-PCR products (GenBank Accession No. EU515126) amplified from infected celery had 90 to 98% nucleotide identity to ApVY. When the deduced amino acid sequences of NIb and CP regions from both cilantro and celery were used for comparison, they showed 95 to 99% identity with the known ApVY GenBank sequences mentioned above. More than 10 asymptomatic parsley plants growing in fields adjacent to the infected celery were also tested for ApVY and found to be infected. ApVY was previously identified in three Apiaceae weeds in Australia (2) and in celery in New Zealand (3). To our knowledge, this is the first report of ApVY on cilantro, celery, and parsley in California. References: (1) J. Chen et al. Arch. Virol. 146:757, 2001. (2) J. Moran et al. Arch. Virol. 147:1855, 2002. (3) J. Tang et al. Plant Dis. 91:1682, 2007.

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First Report of Alternanthera mosaic virus Infection in Angelonia in the United States

Plant Disease ◽

10.1094/pdis-92-10-1473b ◽

2008 ◽

Vol 92 (10) ◽

pp. 1473-1473 ◽

Cited By ~ 7

Author(s):

B. E. Lockhart ◽

M. L. Daughtrey

Keyword(s):

United States ◽

Nucleotide Sequence ◽

Mosaic Virus ◽

Genomic Sequence ◽

Nutrient Deficiency ◽

Leaf Tissue ◽

The United States ◽

Nucleotide Sequence Analysis ◽

Degenerate Primers ◽

First Report

Stunting, chlorosis, and light yellow mottling resembling symptoms of nutrient deficiency were observed in angelonia (Angelonia angustifolia) in commercial production in New York. Numerous, filamentous particles 520 to 540 nm long and spherical virus particles 30 nm in diameter were observed by transmission electron microscopy (TEM) in negatively stained partially purified extracts of symptomatic Angelonia leaf tissue. Two viruses, the filamentous potexvirus Alternanthera mosaic virus (AltMV) and the spherical carmovirus Angelonia flower break virus (AnFBV) were subsequently identified on the basis of nucleotide sequence analysis of amplicons generated by reverse transcription (RT)-PCR using total RNA isolated from infected leaf tissue. A 584-bp portion of the replicase-encoding region of the AltMV genome was obtained with the degenerate primers Potex 2RC (5′-AGC ATR GNN SCR TCY TG-3′) and Potex 5 (5′-CAY CAR CAR GCM AAR GAT GA-3′) (3). Forward (AnFBV CP 1F-5′-AGC CTG GCA ATC TGC GTA CTG ATA-3′) and reverse (AnFBV CP 1R-5′-AAT ACC GCC CTC CTG TTT GGA AGT-3′) primers based on the published AnFBV genomic sequence (GenBank Accession No. NC_007733) were used to amplify a portion of the viral coat protein (CP) gene. The nucleotide sequence of the amplicon generated using the potexvirus-specific primers (GenBank Accession No. EU679362) was 99% identical to the published AltMV (GenBank Accession No. NC_007731) sequence and the nucleotide sequence of the amplicon obtained using the AnFBV CP primers was 99% identical to the published AnFBV genomic sequence (GenBank Accession No. EU679363). AnFBV occurs widely in angelonia (1) and AltMV has been identified in phlox (2). These data confirm the presence of AltMV and AnFBV in diseased angelonia plants showing stunting and nutrient deficiency-like symptoms and substantiates, to our knowledge, this first report of AltMV in angelonia in the United States. References: (1) S. Adkins et al. Phytopathology 96:460, 2006. (2) J. Hammond et al. Arch. Virol. 151:477, 2006. (3) R. A. A. van der Vlugt and M. Berendeson. Eur. J. Plant Pathol. 108:367, 2002.

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First Report of Alfalfa mosaic virus Infection in Viburnum tinus in Chile

Plant Disease ◽

10.1094/pdis-05-11-0414 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1198-1198 ◽

Cited By ~ 2

Author(s):

E. Peña ◽

E. Olate ◽

R. A. Chorbadjian ◽

I. M. Rosales

Keyword(s):

Mosaic Virus ◽

Alfalfa Mosaic Virus ◽

Leaf Tissue ◽

Aphid Species ◽

Molecular Probes ◽

Rt Pcr ◽

Water Control ◽

Tissue Samples ◽

Aphis Spiraecola ◽

Blastn Analysis

Viburnum tinus L., commonly known as laurustinus, is an ornamental shrub that is widely used as a garden plant and flower crop. V. tinus is popular because of its desirable characteristics such as evergreen foliage, tolerance to pruning, winter blooms, and its adaptation to cold temperate zones. It is also relatively easy to grow and is commonly used as a windbreak. Infection of this ornamental species by Alfalfa mosaic virus (AMV) has been associated with yellow mottling or variegated leaf coloring, including light green and white, and has been referred to as the “Viburnum Calico” (1,4). In April 2011, at the onset of winter in the Southern Hemisphere, intense yellow spotting and mottling was observed on V. tinus leaves in the San Joaquin Campus at Pontificia Universidad Catolica de Chile. Presence of Aphis spiraecola Patch was observed on the shrubs, however, in the area it is also common to find other aphid species such as Toxoptera aurantii (Boyer de Fonscolombe) and A. fabae Scopoli. Leaf tissue samples from 10 asymptomatic and 10 symptomatic plants were examined for the presence of AMV by tissue-blot immunoassay with a commercially available polyclonal antibody (Agdia Inc., Elkhart, IN) along with the Goat affinity purified anti-rabbit IgG conjugated (Whole Molecule) (Molecular Probes, Invitrogen Corp., Carlsbad, CA). First-strand cDNA synthesis and PCR were performed with specific primers CP-AMV1 and CP-AMV2 (3). AMV was detected in all symptomatic leaves and also in two of the asymptomatic tissue analyzed by tissue blot assay. Reverse transcription (RT)-PCR produced 753-bp amplicons in all samples that were positive to AMV by tissue printing. No amplification product was observed when water control or seronegative samples were used as templates in the RT-PCR assays. Two amplicons were directly sequenced in both directions to confirm the identification of AMV in the leaf samples. The sequences obtained were homologous and BLASTN analysis of the submitted sequence (GenBank Accession No. JN040542) showed 99% nucleotide sequence identity to an AMV isolate described from Nicotiana tabacum L. (GenBank Accession No. FJ527749). These results demonstrate the presence of AMV in V. tinus in Chile. This pathogen has also been described to be affecting V. tinus in France (1) and V. lucidum Mill. in Spain (2). In Chile, V. tinum is increasingly grown as an ornamental plant. Therefore, care should be taken to ensure that the propagative materials of V. tinum are devoid of AMV infection to prevent further spread of this virus. References: (1) L. Cardin et al. Plant Dis. 90:1115, 2006. (2) M. Cebrián et al. Plant Dis. 92:1132, 2008. (3) M. Finetti-Sialer et al. J. Plant Pathol. 79:115, 1997. (4) H. E. Williams et al. Phytopathology 61:1305, 1971.

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