Report Of Alfalfa Mosaic Virus Research Articles

First Report of Alfalfa Mosaic Virus on Cowpea in the United States

Cowpea ( Vigna unguiculata) is grown on approximately 5,220 ha across California and several Midwestern and southern states. In August of 2020, a viral disease was observed infecting cowpea in commercial fields and research trials in Nebraska, United States. Based on RNA sequencing and serology, the virus species was identified as Alfalfa mosaic virus. To our knowledge, this is the first report of this virus on cowpea in the United States.

First report of alfalfa mosaic virus on Petroselinum crispum in Turkey

First report of alfalfa mosaic virus on Petroselinum crispum in Turkey

First Report of Alfalfa mosaic virus in Chayote in Italy.

Chayote (Sechium edule (Jacq.) Sw.) is a vigorous perennial and climbing cucurbits, native to Mesoamerica, and cultivated for alimentary purposes in the American continent, Australia, New Zealand, South Europe, Asia and Africa. During spring 2019, some chayote plants showing bright yellow vein banding rings and lines were observed in a private garden in South Italy (Campania region). Symptoms coalesced in some leaves, covering almost the whole foliar area. Double-stranded RNAs were extracted from symptomatic leaves of a single chayote plant and reverse-transcribed, randomly amplified, and submitted to Illumina sequencing (Marais et al., 2018). Reads were assembled using CLC Genomics Workbench 11.1 (http://www.clcbio.com). Contigs were then annotated by Blastn and Blastx comparison with the Genbank database, which allowed the identification of eight contigs of between 380 and 980 nucleotides sharing significant identity with alfalfa mosaic virus (AMV) genomic RNAs. No other viral contigs were identified. Mapping of reads on AMV genomic RNAs identified 4,209 AMV reads (1.26% of total reads) and allowed the scaffolding of the contigs into three scaffolds corresponding to the three AMV genomic RNAs. To complete the sequence of the AMV chayote isolate genome (named See-1), primers were designed from the contig sequences and used to amplify RACE PCR products spanning the 5' and 3' terminal regions of the three genomic RNAs using the SMARTer™ RACE cDNA Amplification Kit (Clontech, China). All amplicons were cloned into the pGEM-T vector (Promega, USA) and sequenced (three clones for each amplicon) by Microsynth Seqlab (Microsynth AG, Switzerland). Finally, the complete genomic sequences of the three RNAs were assembled by MacVector 17.5 (MacVector Inc., USA). The RNA1, RNA2 and RNA3 of See-1 are 3,643, 2,593 and 2,037 nt respectively (GenBank accession Nos. MT093209 to MT093211), and share the highest nt sequence identity with the RNA1 and RNA3 of AMV isolate (HZ) from tobacco (99.5% for RNA1, HQ316635; 98.7% for RNA3, HQ316637) and with the RNA2 of isolate AMV-Gym from Gynostemma pentaphyllum (98.1%, MH332898), both from China. AMV isolate See-1 was classified as belonging to subgroup I based on the presence of a BamH I and two AvaII sites in the CP ORF (Parrella et al., 2000). Reverse transcription polymerase chain reaction, using primers targeting the CP gene (Parrella et al., 2000), confirmed AMV infection in three symptomatic cayote plants including that used for Illumina sequencing, with 100% of nt sequence identity of amplicons. Three plants each of Chenopodium amaranticolor, Nicotiana benthamiana and Solanum lycopersicon were mechanically inoculated with sap from isolate See-1 infected plant, leading to the appearance of typical AMV symptoms in all three hosts ten days post-inoculation (Jaspars & Bos, 1980). This note describes the first detection of AMV in cayote in Italy and, to the best of our knowledge, in the world. In some areas of Southern Italy, climatic conditions are favorable enough to allow chayote development in the wild. Further studies would be desirable to determine the distribution and incidence of AMV in chayote and to understand the possibility that this species may play a role in AMV epidemiology, representing a threat to other susceptible crops.

First Report of Alfalfa Mosaic Virus on Soybean in Heilongjiang, China

First Report of Alfalfa Mosaic Virus on Soybean in Heilongjiang, China

First report of alfalfa mosaic virus in Cayratia japonica, Justicia procumbens and Veronica persica in China

First report of alfalfa mosaic virus in Cayratia japonica, Justicia procumbens and Veronica persica in China

First Report of Alfalfa mosaic virus in Red Pepper Plants in Ecuador

First Report of <i>Alfalfa mosaic virus</i> in Red Pepper Plants in Ecuador

First Report of Alfalfa mosaic virus on Safflower in Serbia

First Report of <i>Alfalfa mosaic virus</i> on Safflower in Serbia

First Report of Alfalfa mosaic virus Infecting Lavandula × intermedia in Croatia.

Lavandin (Lavandula × intermedia Emeric ex Loiseleur) is cultivated on a large scale in some South European countries for the extraction of essential oils or as an ornamental plant for gardens and landscapes. In May of 2012, virus-like symptoms including bright yellow calico mosaic, leaf distortion, and growth reduction were observed on 15% of lavandin plants in a commercial nursery in Banovo Brdo locality, Baranja County, Republic of Croatia. Leaves from 15 symptomatic lavandin plants were collected and examined by double-antibody sandwich (DAS)-ELISA using commercial antisera (Bioreba AG, Reinach, Switzerland) against two viruses known to infect Lavandula spp.: Alfalfa mosaic virus (AMV) and Cucumber mosaic virus (CMV) (2,3). Commercial positive and negative controls and extracts from healthy lavandin leaves were included in each ELISA. Only AMV was detected serologically in all 15 tested samples. Five plants each of Chenopodium quinoa, C. amaranticolor, and Nicotiana benthamiana were mechanically inoculated with sap from an ELISA-positive sample (70-12) using 0.01 M phosphate buffer (pH 7). Local chlorotic spots accompanied by systemic mosaic on both Chenopodium species and bright yellow mosaic on N. benthamiana were observed 6 and 12 days post-inoculation, respectively. Test plants were assayed by DAS-ELISA and all inoculated plants of each species tested positive for AMV. The presence of AMV in all symptomatic lavandin plants was further confirmed by reverse transcription (RT)-PCR assay. Total nucleic acid was extracted using RNeasy Plant Mini Kit (Qiagen, Hilden, Germany). RT-PCR was performed with the One-Step RT-PCR Kit (Qiagen) using AMV specific primer pair CP AMV1 (5'-TCCATCATGAGTTCTTCAC-3') and CP AMV2 (5'-AGGACTTCATACCTTGACC-3') (1). Total RNAs obtained from the Serbian AMV isolate from alfalfa (GenBank Accession No. FJ527748) and healthy L. × intermedia plant served as the positive and negative control, respectively. The 751-bp amplicons, covering the partial coat protein (CP) gene and 3'-UTR, were obtained from all 15 samples that were serologically positive to AMV as well as from positive control. No amplification product was observed when extract from healthy L. × intermedia plant was used as template in the RT-PCR assay. The RT-PCR product derived from isolate 70-12 was directly sequenced in both directions using the same primer pair as in RT-PCR and deposited in GenBank (JX996119). Multiple sequence alignment of the CP open reading frame was performed by MEGA5 software (4) and revealed that the isolate 70-12 showed the highest nucleotide identity of 99.4% (99.5% amino acid identity) with Serbian AMV isolate from tobacco (FJ527749). To our knowledge, this is the first report of AMV on L. × intermedia in Croatia. Because lavandin is an aromatic plant traditionally and widely grown in Croatia, the presence of AMV could be a limiting factor for its successful production.

First Report of Alfalfa mosaic virus Occurrence in Tecoma capensis in the USA

Tecoma capensis or cape honeysuckle is an evergreen vine-line shrub that is widely used as a landscape plant in many areas of the southern and western USA. This is the first report of Alfalfa mosaic virus (AMV) infection associated with a disease of T. capensis outside of Israel and Spain. In addition to the effect on marketability, AMV infection in cape honeysuckle may be a source of infection of other susceptible crop species since AMV is readily transmitted in a nonpersistent manner by at least 13 species of aphid. Accepted for publication 11 July 2012. Published 24 August 2012.

First report of Alfalfa mosaic virus in eggplant in Turkey.

Coleus (Coleus blumei) is an ornamental plant hosting several species of the genus Coleviroid [type member Coleus blumei viroid 1 (CbVd-1)], family Pospiviroidae. CbVd-3, a recognized member of the family, has only been reported from Germany in 1996 (Spieker et al., 1996). According to their proposed rod-like secondary structure, the left portion of CbVd-3 is also preserved in CbVd-2 and CbVd-6, which are viroid chimeras (Spieker, 1996; Hou et al., 2009). Fifty leaf samples of coleus, including 30 from Beijing and five each from Tianjin, Nanjing, Fujian and Hainan (China), were collected from 2009 to 2010. Low molecular weight RNAs were extracted as previously reported (Li et al., 1995). RNA extraction from viroid-free coleus was used as negative control. Results of dot-blot hybridization using DIG-labeled CbVd-3 cRNA probe and RT-PCR using CbVd-3 specific primers (PF: 5’-CGGGTACCCAGCAACCTGCT-3’; PR: 5’-TGGGTACCCGCGAAGAGC-3’) showed that one sample from Beijing and one from Hainan were positive for CbVd-3. Products of the expected size were amplified only from the hybridization-positive samples. After cloning, sequence analysis of five selected clones revealed that the similarities between the sequences we obtained and the CbVd-3 sequence reported previously (GenBank accession No. X57294) varied from 99.72% to 100%. The dominant sequence has been submitted to GenBank (accession No. HQ727548). These results provide experimental evidence that the two tested plants were infected by CbVd-3. To our knowledge, this is the first report of CbVd-3 from China and the only report of this viroid outside Germany.

Distribution and Incidence of Some Aphid and Leafhopper Transmitted Viruses Infecting Sugar Beets in Iran.

The main areas for field-grown sugar beet (Beta vulgaris) production in Iran were surveyed to study the occurrence and incidence of Alfalfa mosaic virus (AlMV), Beet curly top virus (BCTV), Beet mosaic virus (BtMV), Beet western yellows virus (BWYV), Beet yellows virus (BYV), Chickpea chlorotic dwarf virus (CpCDV), Cucumber mosaic virus (CMV), and Turnip mosaic virus (TuMV) during the growing season of 2001. A total of 5,292 random leaf samples in addition to 1,294 symptomatic leaves were collected from nine commercial sugar beet growing provinces of Iran and tested by tissue-blot immunoassay (TBIA). Serological diagnoses were confirmed by electron microscopy and host range studies. The highest virus incidence among the surveyed provinces was recorded in Qazvin, followed by Fars, Esfahan, Azarbayejan-e-gharbi, Khorasan, Kermanshah, Semnan, and Hamedan. According to the TBIA results, viruses in decreasing order of incidence in sugar beet were BCTV (27.9%), followed by BWYV (17.4%), CpCDV (12.5%), BYV (10.6%), BtMV (7.4%), TuMV (2.9%), AlMV (1.3%), and CMV (1.2%). Nearly 35% of sugar beets in Iran were infected by one or both of the two leafhopper-transmitted viruses (BCTV and CpCDV). Moreover, about 28% were infected by at least one of the six aphid-transmitted viruses (AlMV, BWYV, BtMV, BYV, CMV, and TuMV). Overall, one or more of the eight viruses assayed were detected in 45.5% of the plants surveyed. Several plants (35%) displaying virus-like symptoms did not react with the virus antisera used, suggesting that more viruses or virus-like agents are infecting sugar beets in Iran. In reference to the earlier reports, this is the first report of AlMV and TuMV in sugar beet fields of Iran. Also, this is the first detection of CpCDV as a pathogen of sugar beet.

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

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

First Report of Alfalfa mosaic virus in Lavandula officinalis.

For several years, in ornamental nurseries in the Mediterranean area of Spain, stunting and yellow leaf spotting have been observed in young plants of Lavandula officinalis. Symptoms eventually disappeared as the plants matured. During the summer of 2003, the number of plantlets affected and the intensity of symptoms increased significantly. Symptomatic plants tested positive using enzyme-linked immunosorbent assay (ELISA) (Phyto-Diagnostics, INRA, France) for the presence of Alfalfa mosaic virus (AMV). ELISA results were verified using reverse transcription-polymerase chain reaction (RT-PCR). Total RNA extracts from symptomatic plants were analyzed using primers designed specifically for the coat protein region of AMV utilizing sequence data from GenBank Accession No. AF215664: AMVcoat-F: GT GGT GGG AAA GCT GGT AAA and AMVcoat-R: CAC CCA GTG GAG GTC AGC ATT. The thermocycling schedule was as follows: reverse transcriptase step at 50°C for 30 min, first PCR cycle at 94°C for 2 min, 35 cycles each of 30 s at 94°C, 30 s at 54°C, 30 s at 72°C, followed by a final extension at 72°C for 10 min. A 700-pb PCR product of the expected size was obtained from plants that were positive for AMV using ELISA. The two systems provide for rapid detection of AMV in L. officinalis. A regular screening program will assist in providing virus-free plants to ornamental nurseries. These results demonstrate the presence of AMV in L. officinalis. Alfalfa (Medicago sativa L.) is a typical source of AMV. However, because the nurseries where L. officinalis is grown are not in the vicinity of alfalfa fields, we suggest the source of the infection originated in the propagation material. AMV has currently been reported in L. officinalis only in Italy and France (1). To our knowledge, this is the first report of AMV in L. officinalis in Spain. Reference: (1): A. Garibaldi et al. Ed. Edagricole-Edisioni Agricole della Calderini s.r.l., Bologna, 2000.

First Report of a Disease of Peony Caused by Alfalfa mosaic virus.

During the summers of 2001 and 2002, Japanese peony (Paeonia albiflora Pall., synonym P. lactiflora, family Paeoniaceae) plants, cultivated in the Botanical Garden of the University of Parma (Emilia Romagna Region of northern Italy), were found affected by a disease with virus-like symptoms. The oldest leaves showed yellow, mosaic, oak-like arabesques and line-patterns; the remaining leaves and pink flowers were symptomless. A disease of peony, known as peony ring spot disease, has been reported worldwide (Europe, United States, Japan, and New Zeland) for several years and is associated with strains of Tobacco rattle virus (TRV) (1). Electron microscopic observations of peony leaf sap (leaf dip preparations stained with uranyl acetate and phospotungstic acid) did not show the presence of any rod-shaped virus particles, including TRV. Mechanical inoculations of sap from symptomatic leaves caused symptoms typical of Alfalfa mosaic virus (AMV) on Chenopodium amaranticolor Coste & Reyn. (local chlorotic and necrotic lesions and systemic periveinal line-patterns), Ocimum basilicum L. (yellow mosaic), Vigna unguiculata (L.) Walp. (red, local necrotic lesions), and Nicotiana tabacum cv. Samsun (white, necrotic lesions, systemic leaf malformation, and mosaic), and N. glutinosa L. (systemic leaf variegation). Symptomatic leaves of peony and infected herbaceous plants were analyzed for virus presence by protein A sandwich enzyme-linked immunosorbent assay (PAS-ELISA). The polyclonal antisera tested were those to AMV (PVAS 92, American Type Culture Collection, Manassas, VA), AMV-Vinca minor L. (DiSTA collection, Italy), and the nepoviruses Strawberry latent ringspot virus, Tomato ringspot virus, and Cherry leaf roll virus. PAS-ELISA revealed only the presence of AMV. Immunoelectron microscopy and gold-labeled decoration confirmed the identity of the virus. In 2001, five symptomless peony plants (provided by a commercial grower and previously analyzed for AMV and TRV presence) were grafted with shoots from peony showing yellow mosaic on the leaves and maintained in a greenhouse under aphid-proof cage. During the summer of 2002, one of the grafted plants showed a mild mosaic on the leaves; PAS-ELISA revealed this peony was infected by AMV. To our knowledge, this is the first report of AMV in peony. Reference: (1) Chang et al. Ann. Phytopathol. Soc. Jpn. 42:325, 1976.

First Report of Alfalfa mosaic virus in Kura Clover (Trifolium amgibuum) in Wisconsin.

Kura clover (Trifolium ambiguum M. Bieb.) has been reported to be resistant to several viruses, including Alfalfa mosaic virus (AMV), Bean yellow mosaic virus (BYMV), Clover yellow vein virus (CYVV), Peanut stunt virus, Red clover vein mosaic virus (RCVMV), and White clover mosaic virus (WCMV) (2). Furthermore, 54 of 61 kura clover plants were resistant to Clover yellow mosaic virus (CYMV). Field-grown kura clover plants had no visual symptoms of virus infection, but a small proportion of plant introductions tested positive for CYVV, WCMV, and RCVMV (1). These and similar studies have given kura clover the reputation of being highly resistant to most viruses that affect other forage legumes. Viral-like symptoms, characterized by mosaic, crinkling, and reduced size of leaflets were observed on 53 kura clover plants in an 88-plant collection (plant introductions and cultivars) growing in the field. A 20-plant subset was screened for AMV, Bean pod mottle virus, BYMV, Soybean mosaic virus, Tobacco ring spot virus, and Tobacco streak virus using enzyme-linked immunosorbent assay (ELISA). Only AMV was found, and it was detected in nine plants. To our knowledge, this is the first report of AMV in kura clover. The remaining 68 plants were tested for AMV. In total, 70 plants were positive, and 18 plants were negative. AMV was detected in leaves and rhizomes of kura clover. Simultaneously, plants were scored on two occasions for interveinal mosaic, yellowing, curling of leaves, and general chlorosis. There was no correlation between visual symptoms and ELISA results. Results from ELISA were confirmed with a local lesion assay on 'Bountiful' beans (Phaseolus vulgaris L.). Leaves from three AMV-positive plants were bulked and ground in phosphate buffer (pH 7.0). Leaves of challenge plants were dusted with Carborundum, and infected sap was rubbed on the youngest leaf of each plant. This procedure was repeated with leaves from three AMV-negative plants. All 12 bean plants inoculated with sap from AMV-positive kura clover developed local lesions or systemic reactions. None of the 12 negative controls developed local lesions. The transmission of AMV from one kura clover plant to another was attempted with the inoculation procedure described above, except that a phosphate-sulfite buffer was used and with soybean aphids (Aphis glycines Matsamura). Seven virus-free 'Endura' kura clover plants were inoculated with sap from AMV-positive kura clover plants, and five negative control plants were included. Ten other plants were inoculated with AMV using soybean aphids. Aphids were allowed to feed for 3 min on AMV-positive kura clover plants, then allowed to feed, 10 per plant, on AMV-negative plants. There were six negative controls for this treatment. Three weeks after inoculation, top-growth was clipped, and 9-week-old regrowth was tested for AMV. Two of the mechanically inoculated plants tested positive for AMV using ELISA, and infection was further confirmed by the local lesion assay described above. Therefore, it is demonstrated that AMV can be mechanically transmitted to kura clover. AMV was not transmitted by the colony of soybean aphids, which previously transmitted AMV to soybean (3). This suggests virus-strain aphid specificity and possibly host specificity for phid transmission of AMV to kura clover.

First Report of Alfalfa Mosaic Virus in Lupins in Australia

First Report of Alfalfa Mosaic Virus in Lupins in Australia