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

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1198-1198 ◽  
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.

scholarly journals First Report of Alfalfa mosaic virus in Viburnum lucidum in Spain

Plant Disease ◽  
2008 ◽  
Vol 92 (7) ◽  
pp. 1132-1132 ◽  
Author(s):  
M. C. Cebrián ◽  
M. C. Córdoba-Sellés ◽  
A. Alfaro-Fernández ◽  
J. A. Herrera-Vásquez ◽  
C. Jordá
Keyword(s):  
Mosaic Virus ◽  
Natural Infection ◽  
Alfalfa Mosaic Virus ◽  
The United States ◽  
Rt Pcr ◽  
Water Control ◽  
First Report ◽  
Pcr Product ◽  
Pcr Assays ◽  
The Mediterranean

Viburnum sp. is an ornamental shrub widely used in private and public gardens. It is common in natural wooded areas in the Mediterranean Region. The genus includes more than 150 species distributed widely in climatically mild and subtropical regions of Asia, Europe, North Africa, and the Americas. In January 2007, yellow leaf spotting in young plants of Viburnun lucidum was observed in two ornamental nurseries in the Mediterranean area of Spain. Symptoms appeared sporadically depending on environmental conditions but normally in cooler conditions. Leaf tissue from 24 asymptomatic and five symptomatic plants was sampled and analyzed by double-antibody sandwich (DAS)-ELISA with specific polyclonal antibodies against Tomato spotted wilt virus (TSWV) (Loewe Biochemica, Sauerlach, Germany) and Alfalfa mosaic virus (AMV) (SEDIAG S.A.S, Longvic, France). All symptomatic plants of V. lucidum were positive for Alfalfa mosaic virus (AMV). The presence of AMV was tested in the 29 samples by one-step reverse transcription (RT)-PCR with the platinum Taq kit (Invitrogen Life Technologies, Barcelona, Spain) using primers derived from a partial fragment of the coat protein gene of AMV (2). The RT-PCR assays produced an expected amplicon of 700 bp in the five symptomatic seropositive samples. No amplification product was observed when healthy plants or a water control were used as a template in the RT-PCR assays. One PCR product was purified (High Pure PCR Product Purification Kit; Roche Diagnostics, Mannheim, Germany) and directly sequenced (GenBank Accession No. EF427449). BLAST analysis showed 96% nucleotide sequence identity to an AMV isolate described from Phlox paniculata in the United States (GenBank Accession No. DQ124429). This virosis has been described as affecting Viburnum tinus L. in France (1). To our knowledge, this is the first report of natural infection of Viburnum lucidum with AMV in Spain, which might have important epidemiological consequences since V. lucidum is a vegetatively propagated ornamental plant. References: (1) L. Cardin et al. Plant Dis. 90:1115, 2006. (2) Ll. Martínez-Priego et al. Plant Dis. 88:908, 2004.

scholarly journals A Description of the Possible Etiology of the Cilantro Yellow Blotch Disease

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 630-633
Author(s):  
Olufemi J. Alabi ◽  
Brianna C. Gaytán ◽  
Maher Al Rwahnih ◽  
Cecilia Villegas
Keyword(s):  
High Throughput Sequencing ◽  
Disease Incidence ◽  
Natural Infection ◽  
Alfalfa Mosaic Virus ◽  
Leaf Tissue ◽  
Rt Pcr ◽  
Specific Primers ◽  
Tissue Samples ◽  
Pcr Assays ◽  
Hidalgo County

A virus-like disease characterized by foliar yellow blotch symptoms and resembling those described for cilantro yellow blotch disease in California was observed in a 4.05-ha cilantro (Coriandrum sativum) cv. Santo field in Hidalgo County, Texas during spring 2019. Disease incidence at harvest was estimated at ∼20%, and the affected plants were rendered unmarketable. Foliar systemic chlorosis symptoms were observed on sap-inoculated Nicotiana occidentalis plants (n = 3) using inocula from symptomatic cilantro. Total RNA aliquots from 11 randomly collected leaf tissue samples (symptomatic = 7, asymptomatic = 4) were pooled into a composite cilantro RNA sample which was analyzed by high throughput sequencing (HTS). Analyses of the obtained 15.7 million raw reads (76 nt each) yielded virus-specific contigs that mapped to the genomes of alfalfa mosaic virus (AMV), beet pseudoyellows virus (BPYV), and lettuce chlorosis virus (LCV). Virus-specific primers designed from the HTS-derived sequences were used to screen the samples in two-step RT-PCR assays, resulting in the detection of AMV+BPYV in 3 of 7 symptomatic cilantro samples, AMV+LCV in 4 of 7 symptomatic cilantro samples, and AMV alone in the 4 asymptomatic cilantro and sap-inoculated N. occidentalis samples. The results represent the first reports of the natural infection of cilantro by BPYV and LCV and implicate the mixed infection of a Crinivirus and AMV in cilantro yellow blotch disease.

scholarly journals First Report of Alfalfa mosaic virus Occurrence in Hydrangea in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (9) ◽  
pp. 1258-1258 ◽  
Author(s):  
B. Lockhart ◽  
D. Mollov ◽  
M. Daughtrey
Keyword(s):  
Electron Microscopy ◽  
United States ◽  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Leaf Tissue ◽  
The United States ◽  
Spherical Particles ◽  
Genomic Sequences ◽  
Rt Pcr ◽  
First Report

In spring of 2012, a previously unrecorded virus-like disease characterized by conspicuous yellow leaf blotching (calico symptoms) was observed in plants of Hydrangea macrophylla in a single location in Southampton, NY. Bacilliform and spherical particles resembling those of Alfalfa mosaic virus (AMV) were observed by transmission electron microscopy (TEM) in partially purified extracts from symptomatic leaf tissue. The identity of the virus was confirmed by immunosorbent electron microscopy (ISEM) (4) using antiserum to AMV (ATCC PVAS 92) that both trapped and decorated the virions. Three primer pairs designed from available AMV RNA 1, RNA 2, and RNA 3 genomic sequences were used to generate amplicons from the hydrangea AMV isolate. Reverse-transcription (RT)-PCR was done using total RNA extracted from symptomatic hydrangea leaf tissue with a Qiagen RNeasy kit, and Ready-to-Go RT-PCR beads (GE Healthcare). Amplicons of 1,049, 1,013, and 658 bp were obtained using the primer pairs AMV1F (5′-ATCCACCGATGCCAGCCTTA)/AMV1R (5′-TTCCGCCTCACTGCTGTCTG), AMV2F (5′-GATCGCCGGAAGTGATCCAG)/AMV2R (5′-TCACCGGAAGCAACAACGAA), and AMV3F (5′-GCCGGTTCTCCAAAGGGTCT)/AMV3R (5′-CGCGTCGAAGTCCAGACAGA), respectively. The PCR products were cloned using a TOPO TA cloning kit (Invitrogen) and three clones of each were sequenced. The sequences obtained from the hydrangea AMV RNA 1 (JX154090), RNA 2 (JX154091), and RNA 3 (JX154092) had 95 to 98% nucleotide sequence identity to homologous genomic sequences of known AMV isolates. To our knowledge, this is the first report of AMV occurrence in H. macrophylla in the United States. This virus has been reported to occur in H. macrophylla in British Columbia (3), but in a previous survey its presence was not detected in hydrangeas in the United States (1). A report of possible AMV infection in H. macrophylla in Italy (2) was based solely on symptomatology and cross-protection tests and therefore cannot be verified. The AMV-infected hydrangea plants were found by ISEM to also contain low concentrations of Hydrangea ringspot virus (HRSV) and Hydrangea chlorotic mottle virus (HdCMV). However, based on previous evidence of single and mixed infections (3), it is unlikely that the calico symptoms observed were influenced by the presence of HRSV and HdCMV. This report is of interest both because AMV, unlike HRSV and HdCMV, causes foliar symptoms that would render hydrangea plant unmarketable, and because the disease can be spread by a number of common aphid species that transmit AMV. It will also serve to alert growers and diagnosticians to the potential threat posed by AMV infection. References: (1) T. C. Allen et al. Acta Hortic. 164:85, 1985. (2) G. Belli. Phytopathol. Mediterr. 7:70, 1968. (3) A. W. Chiko and S. E. Godkin. Plant Dis. 70:541, 1986. (4) B. E. L. Lockhart et al. Phytopathology 82:691, 1992.

scholarly journals Identification, Characterization, and Molecular Detection of Alfalfa mosaic virus in Potato

2006 ◽  
Vol 96 (11) ◽  
pp. 1237-1242 ◽  
Author(s):  
H. Xu ◽  
J. Nie
Keyword(s):  
Mosaic Virus ◽  
Gene Sequence ◽  
Alfalfa Mosaic Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Polymorphism Analysis ◽  
Rt Pcr ◽  
Potato Leaf ◽  
Simple Method ◽  
Cp Gene ◽  
Nucleotide Sequence Alignment

Alfalfa mosaic virus (AMV) was detected in potato fields in several provinces in Canada and characterized by bioassay, enzyme-linked immunosorbent assay, and reverse-transcription polymerase chain reaction (RT-PCR). The identity of eight Canadian potato AMV isolates was confirmed by sequence analysis of their coat protein (CP) gene. Sequence and phylogenetic analysis indicated that these eight AMV potato isolates fell into one strain group, whereas a slight difference between Ca175 and the other Canadian AMV isolates was revealed. The Canadian AMV isolates, except Ca175, clustered together among other strains based on alignment of the CP gene sequence. To detect the virus, a pair of primers, AMV-F and AMV-R, specific to the AMV CP gene, was designed based on the nucleotide sequence alignment of known AMV strains. Evaluations showed that RT-PCR using this primer set was specific and sensitive for detecting AMV in potato leaf and tuber samples. AMV RNAs were easily detected in composite samples of 400 to 800 potato leaves or 200 to 400 tubers. Restriction analysis of PCR amplicons with SacI was a simple method for the confirmation of PCR tests. Thus, RT-PCR followed by restriction fragment length polymorphism analysis may be a useful approach for screening potato samples on a large scale for the presence of AMV.

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

Plant Disease ◽  
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.

scholarly journals Pathogenesis of Alfalfa mosaic virus in Soybean (Glycine max) and Expression of Chimeric Rabies Peptide in Virus-Infected Soybean Plants

2001 ◽  
Vol 91 (10) ◽  
pp. 941-947 ◽  
Author(s):  
Nina Fleysh ◽  
Deepali Deka ◽  
Maria Drath ◽  
Hilary Koprowski ◽  
Vidadi Yusibov
Keyword(s):  
Glycine Max ◽  
Mosaic Virus ◽  
Seed Coat ◽  
Alfalfa Mosaic Virus ◽  
Soybean Seed ◽  
Value Added ◽  
Plant Viruses ◽  
Tissue Samples ◽  
Seed Formation ◽  
Soybean Plants

Infection of soybean (Glycine max) plants inoculated with particles of Alfalfa mosaic virus (AlMV) isolate 425 at 12 days after germination was monitored throughout the life cycle of the plant (vegetative growth, flowering, seed formation, and seed maturation) by western blot analysis of tissue samples. At 8 to 10 days after inoculation, the upper uninoculated leaves showed symptoms of virus infection and accumulation of viral coat protein (CP). Virus CP was detectable in leaves, stem, roots, seedpods, and seed coat up to 45 days postinoculation (dpi), but only in the seedpod and seed coat at 65 dpi. No virus accumulation was detected in embryos and cotyledons at any time during infection, and no seed transmission of virus was observed. Soybean plants inoculated with recombinant AlMV passaged from upper uninoculated leaves of infected plants showed accumulation of full-length chimeric AlMV CP containing rabies antigen in systemically infected leaves and seed coat. These results suggest the potential usefulness of plants and plant viruses as vehicles for producing proteins of biomedical importance in a safe and inexpensive manner. Moreover, even the soybean seed coat, treated as waste tissue during conventional processing for oil and other products, may be utilized for the expression of value-added proteins.

Biodiversity and full genome sequence of potato viruses Alfalfa mosaic virus and potato leaf roll virus in Egypt

2018 ◽  
Vol 73 (11-12) ◽  
pp. 423-438 ◽  
Author(s):  
Engy E. Abdel Aleem ◽  
Radwa M. Taha ◽  
Faiza A. Fattouh
Keyword(s):  
Phylogenetic Analysis ◽  
Nucleotide Sequence ◽  
Mosaic Virus ◽  
Complete Nucleotide Sequence ◽  
Leaf Roll ◽  
Alfalfa Mosaic Virus ◽  
Potato Leaf Roll Virus ◽  
Rt Pcr ◽  
Potato Leaf ◽  
Potato Viruses

Abstract Solanum tuberosum (potato) is the second most important vegetable crop in Egypt. It is locally consumed, manufactured or supplied for export to Europe and other Arab countries. Potato is subject to infection by a number of plant viruses, which affect its yield and quality. Potato virus Y (PVY), potato leaf roll virus (PLRV), and Alfalfa mosaic virus (AMV) were detected in major potato-growing areas surveyed. Multiplex-RT-PCR assay was used for the detection of these three viruses in one reaction using three specific primer pairs designed to amplify genomic parts of each virus (1594 bp for PLRV, 795 bp for AMV, 801 bp for PVY). All three viruses were detected in a single reaction mixture in naturally infected field-grown potatoes. Multiplex RT-PCR improved sensitivity necessary for the early detection of infection. Incidence of single, double, or triple infection has been recorded in some locations. Full-length sequencing has been performed for an Egyptian FER isolate of PLRV. Through phylogenetic analysis, it was shown to occupy the same clade with isolate JokerMV10 from Germany. Complete nucleotide sequence of an Egyptian FER isolate of AMV and phylogenetic analysis was also performed; we propose that it is a new distinct strain of AMV belonging to a new subgroup IIC. This is the first complete nucleotide sequence of an Egyptian isolate of AMV. Genetic biodiversity of devastating potato viruses necessitates continuous monitoring of new genetic variants of such viruses.

scholarly journals Araujia sericifera New Host of Alfalfa mosaic virus in Italy

Plant Disease ◽  
2013 ◽  
Vol 97 (10) ◽  
pp. 1387-1387 ◽  
Author(s):  
G. Parrella ◽  
B. Greco ◽  
G. Cennamo ◽  
R. Griffo ◽  
A. Stinca
Keyword(s):  
Mosaic Virus ◽  
Invasive Plant ◽  
Alfalfa Mosaic Virus ◽  
Rt Pcr ◽  
Systemic Necrosis ◽  
New Host ◽  
Campania Region ◽  
Bright Yellow ◽  
Italian Isolate ◽  
Local Lesions

Araujia sericifera Brot. (Fam. Apocynaceae) is an evergreen climbing plant native of South America, originally introduced in Europe as an ornamental. In spring 2012, virus-like symptoms including bright yellow mosaic of calico-type and leaf distortion were observed in three A. sericifera plants growing in an abandoned field located in Pomigliano d'Arco (Campania region, Italy). Leaves from the three plants were collected and examined using commercial antisera (Bioreba AG, Reinach, Switzerland) by double antibody sandwich (DAS)-ELISA against Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV), and by indirect plate trapped antigen (PTA)-ELISA against potyviruses (Potygroup test). Only AMV was detected serologically in the three A. sericifera samples. The virus was mechanically transmitted from the ELISA-positive samples to four plants each of Chenopodium quinoa, C. amaranticolor, tobacco (Nicotiana tabacum cv. Xanthi nc), cowpea (Vigna unguiculata, cv. Black eyes), basil (Ocimum basilicum, cv. Gigante), and tomato (Solanum lycopersicum cv. San Marzano), using chilled 0.03 M sodium phosphate buffer, containing 0.2% sodium diethyldithiocarbamate, 75 mg/ml of active charcoal, and traces of Carborundum (600 mesh). Inoculated plants were kept in an insect-proof greenhouse with natural illumination and temperatures of 24 and 18°C day/night. Under these conditions, plants showed the following symptoms after 1 to 3 weeks, consistent with symptoms caused by AMV (1): chlorotic local lesions following by mosaic in C. quinoa and C. amaranticolor, reddish local lesions following by mosaic in cowpea, necrotic local lesions followed by systemic necrosis in tomato, bright yellow mosaic (calico type) in basil, and mosaic and strong deformation of the apical leaves in tobacco. The presence of AMV in ELISA-positive A. sericifera and host plants was further confirmed by conventional reverse transcription (RT)-PCR. Total RNAs were extracted with an RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). RT-PCR was performed with the One-Step RT-PCR Kit (Qiagen) using primers for the coat protein gene (CP) previously used for the molecular characterization of AMV isolates (2). An Italian isolate of AMV from Lavandula stoechas (GenBank Accession No. FN667967) and RNA extracted from a healthy A. sericifera plant were used as positive and negative controls, respectively. An amplicon of the correct predicted size (∼750 bp) was obtained from each of the infected plants assayed, and that derived from A. sericifera isolate Ars2 was purified (QIAqick PCR Purification Kit, Qiagen), cloned in pGEMT easy vector (Promega, Fitchburg, WI) and sequenced (HF570950). Sequence analysis of the CP gene, conducted with MEGA5 software, revealed the highest nucleotide identity of 98% (99% amino acid identity) with the AMV isolate Tef-1 (FR854391), an isolate belonging to subgroup I (3). To our knowledge, this is the first report of AMV infecting A. sericifera in Italy. Since A. sericifera is considered an invasive plant, in continuous expansion to new areas in Italy and in other European countries, particular attention should be paid to the possibility that this species may play a role in the epidemiology of aphid-transmitted viruses such as AMV and CMV, representing a threat to susceptible crops growing nearby. References: (1) G. Marchoux et al. Page 163 in: Virus des Solanacées. Quae éditions, Versailles, 2008. (2) G. Parrella et al. Arch. Virol. 145:2659, 2000. (3) G. Parrella et al. Plant Dis. 96:249, 2012.

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

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 573-573 ◽  
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.

scholarly journals First Report of Alfalfa mosaic virus Infecting Basil (Ocimum basilicum) in California

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 295-295 ◽  
Author(s):  
W. M. Wintermantel ◽  
E. T. Natwick
Keyword(s):  
Nucleic Acid ◽  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Plant Viruses ◽  
Ocimum Basilicum ◽  
Mechanical Transmission ◽  
Rt Pcr ◽  
Imperial Valley ◽  
First Report ◽  
Production Region

Basil (Ocimum basilicum L.) plants collected from three fields in Imperial County, CA in May, 2011 were found to be exhibiting yellowing, chlorotic sectors and spots on leaves, resulting in unmarketable plants. Dodder (Cuscuta spp.) was present in one of the fields, but was not visibly associated with symptomatic plants. Total nucleic acid was extracted from four symptomatic and three asymptomatic basil plants, as well as from the dodder plant with the RNeasy Plant Mini Kit (Qiagen, Valencia, CA). Nucleic acid extracts were tested by reverse transcription (RT)-PCR for the presence of Alfalfa mosaic virus (AMV) using primers designed to amplify a 350-nt region of the AMV coat protein gene (3). RT-PCR produced bands of the expected size in extracts from all symptomatic plants and the dodder sample. No amplification was obtained from symptomless plants. A 350-nt band amplified from one plant was gel-extracted, sequenced (TACGen, Richmond, CA), and confirmed to be AMV by comparison to sequences available in GenBank (Accession No. K02703). Although serological tests on an initial basil sample were negative for AMV by ELISA using antiserum produced against AMV by R. Larsen, USDA-ARS, Prosser, WA (unpublished), AMV was confirmed by ELISA and RT-PCR in symptomatic Nicotiana benthamiana, N. clevelandii, and Malva parviflora plants following mechanical transmission from basil source plants. The fields with AMV infections were located at opposite ends of the production region from one another, indicating widespread dispersal of AMV in the region. All AMV positive plants were adjacent to alfalfa. Two additional basil plantings in shade houses open to the outside environment did not have AMV symptomatic plants and were also confirmed negative by RT-PCR, but these plantings were at the extreme north end of Imperial Valley agriculture and well away from any alfalfa fields. At the time the basil plantations were sampled for AMV, no aphids were found in any plantations, but during the several weeks prior to finding the AMV-positive plants, cowpea aphid, Aphis craccivora Koch; pea aphid, Acyrthosiphon pisum Harris; blue alfalfa aphid, Acyrthosiphon kondoi Shinji; and spotted alfalfa aphid, Therioaphis maculata Buckton were colonizing Imperial Valley alfalfa fields, producing winged adults. AMV is transmitted by at least 14 aphid species (1), and most aphid populations increase during the late spring in this important desert agricultural region. The acquisition of AMV by dodder suggests the parasitic plant may serve as a vector of AMV within basil fields, although further study will be necessary for clarification. Significant acreage of basil is grown in the Imperial Valley. This acreage is surrounded by extensive and increasing alfalfa production totaling 55,442 ha (137,000 acres) in Imperial County and representing a 21% increase in acreage over 2009 for the same region (2). To our knowledge, this is the first report of basil infected by AMV in California. The proximity of basil production to such a large alfalfa production region warrants the need for enhanced efforts at aphid management in basil production to reduce vector populations and reduce transmission to basil crops. References: (1) E. M. Jaspars and L. Bos. Alfalfa mosaic virus. No. 229 in: Descriptions of Plant Viruses. Commonw. Mycol. Inst./Assoc. Appl. Biol., Kew, England, 1980. (2) C. Valenzuela. Imperial County California Crop and Livestock Report, 2010. (3) H. Xu and J. Nie. Phytopathology 96:1237, 2006.

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