scholarly journals Identification and Incidence of Iris yellow spot virus, a New Pathogen in Onion and Leek in Greece

Plant Disease ◽  
2009 ◽  
Vol 93 (7) ◽  
pp. 761-761 ◽  
Author(s):  
E. K. Chatzivassiliou ◽  
V. Giavachtsia ◽  
A. H. Mehraban ◽  
K. Hoedjes ◽  
D. Peters

Iris yellow spot virus (IYSV; genus Tospovirus, family Bunyaviridae) is an emerging and serious pathogen affecting several Allium spp. worldwide (2). The virus causes straw-colored, chlorotic or necrotic lesions that coalesce, occasionally resulting in an extensive necrosis on onion (A. cepa L.) leaves. From February to June 2008, 530 onion and 439 leek (A. porum L.) leaf samples showing a variety of lesions were collected from different areas of Greece. All plants sampled were infested with Thrips tabaci Lindeman, the sole thrips species identified as the vector of this virus. Samples were analyzed by double-antibody sandwich (DAS)-ELISA using polyclonal antibodies against the N protein of IYSV (Laboratory of Virology, Wageningen Agricultural University). A higher percentage of onion samples than leek samples were infected, with IYSV detected in 36, 44, 23.7, 61.7, 10, 55, 15.3, and 9.4% of onion samples from the prefectures of Evros, Heraklion, Kavala, Magnissia, Pella, Rodopi, Thessaloniki, and Viotia, respectively, and in 5, 0, 0, 9.3, and 13% of leek samples from Evros, Heraklion, Magnissia, Pella, and Thessaloniki, respectively. No leek samples were tested from Kavala, Rodopi, and Viotia. Sap extracts from some positive samples were mechanically inoculated onto Nicotiana benthamiana leaves, and infected plants developed typical IYSV symptoms and were positive in DAS-ELISA, confirming transmission from the field samples. Viral RNA was extracted from ELISA-positive onion and leek samples and an ~800-bp amplicon was obtained from both hosts by reverse-transcription (RT)-PCR and N-gene primers derived from IYSV (IY1: 5′-CCCGAGGATCCATGGCTACCGTTAGGG-3′ and IY2: 5′-CCCGAGGATCCAAATTAATTATATCTATCTTTCTTGG-3′) (1). These amplicons were cloned and sequenced (GenBank Accession No. FJ785835) and nucleotide sequence comparisons showed a 98 to 99% identity with a Dutch isolate of IYSV (GenBank Accession No AF001387). The virus was transmitted among onion seedlings in the laboratory using a leek population of T. tabaci. Infected seedlings, as determined by DAS-ELISA, developed symptoms similar to those observed in the field samples. To our knowledge, this is the first report of IYSV in Greece; however, the virus seems already to be very well established. References: (1) I. Cortez et al. Phytopathology 88:1276, 1998. (2) D. Gent et al. Plant. Dis. 90:1468, 2006.

Plant Disease ◽  
2010 ◽  
Vol 94 (11) ◽  
pp. 1373-1373 ◽  
Author(s):  
K. Lobin ◽  
A. Saison ◽  
B. Hostachy ◽  
S. P. Benimadhu ◽  
H. R. Pappu

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) transmitted by thrips (Thrips tabaci Lindeman) is an economically important viral pathogen of bulb and seed onion (Allium cepa) crops in many onion-growing areas of the world (2,3). In Africa, IYSV has been reported in Reunion (4) and South Africa (1). In June 2008, diamond-shaped lesions that are typical of IYSV were observed on onion seed scapes in an onion plot of 0.25 ha at Reduit in the central part of Mauritius. Disease incidence was 80% with a severity of 50 to 75% of the scape surface area. Lodging was observed in 25% of the symptomatic plants. Twenty-two symptomatic plants were tested and found to be positive for IYSV when tested by double antibody sandwich (DAS)-ELISA with a commercially available kit (Agdia Inc., Elkhart, IN). The presence of the virus was confirmed by reverse transcription (RT)-PCR tests with primers 917L: 5′-TAAAACTTAACTAACACAAA-3′ and 56U: 5′-TCCTAAGTATTCACCAT-3′ as forward and reverse primers, respectively, for specific sequences flanking the CP gene. Another set of primers specific to the small (S) RNA of IYSV (5′-TAAAACAAACATTCAAACAA-3′ and 5′-CTCTTAAACACATTT AACAAGCAC-3′) produced an amplicon of approximately 1.2 kb that includes the 772-bp nucleocapsid (N) gene. The 1.2-kb amplicon was cloned and four clones were sequenced and consensus sequence was used for comparisons. Sequence analysis showed that the N gene of the IYSV isolate from Mauritius (GenBank Accession No. HM218822) shared the highest nucleotide sequence identity (99%) with several known IYSV N gene sequences (Accession Nos. FJ785835 and AM900393) available in the GenBank, confirming the presence of IYSV in the onion crops in Mauritius. A survey was subsequently carried out from July to November 2008 in major onion-growing localities at La Marie, Henrietta, Reduit, and Plaine Sophie (center); Bassin, La Ferme, and La Chaumiere (west); Grand Sable, Petit Sable, and Plaisance (south, southeast); and Belle Mare, Trou d'Eau Douce, and Palmar (east) to monitor the distribution of the disease on the island. Symptomatic samples with diamond-to-irregularly shaped lesions were observed and 155 symptomatic and 35 nonsymptomatic samples were collected and screened by DAS-ELISA for IYSV and Tomato spotted wilt virus (TSWV), another tospovirus reported to infect onion elsewhere. Sixty-six percent of the symptomatic samples screened (102 of 155) tested positive for IYSV. No IYSV was detected in the symptomless samples. There was no serological indication of TSWV infection in the samples. Samples that tested positive for IYSV were collected from Belle mare, Palmar, and Trou d'eau douce in the east and La Ferme in the west. Cultivars infected were Gandiole, Local Red, and Veronique. No IYSV was detected in the bulbs. The vector, T. tabaci, was observed in infected onion parcels surveyed and is known to occur in all onion-producing areas of the island. To our knowledge, this is the first report of IYSV in onion in Mauritius. Further surveys and monitoring of IYSV incidence, along with its impact on the yield, need to be established. References: (1) L. J. du Toit et al. Plant Dis. 91:1203, 2007. (2) D. H. Gent et al. Plant Dis. 88:446, 2004. (3) H. R. Pappu et al. Virus Res. 141:219, 2009. (4) I. Robène-Soustrade et al. Plant Pathol. 55:288, 2006.


Plant Disease ◽  
2013 ◽  
Vol 97 (12) ◽  
pp. 1665-1665 ◽  
Author(s):  
H. R. Pappu ◽  
A. Rauf

Green onion (Allium fistulosum L.) is an important vegetable crop for small-holder farmers for domestic consumption in Indonesia. Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) transmitted by Thrips tabaci is an economically important viral pathogen of bulb and seed onion crops in many onion-growing areas of the world (1,3). In Asia, IYSV has been reported in India and Sri Lanka (2,4). In April 2013, symptoms suspected to be caused by IYSV were observed on a 1-month-old green onion crop grown for their leaves in a farmer's field in Cipendawa, Pacet, Cianjur District, West Java. Symptoms consisted of elliptical to spindle-shaped, straw colored, irregular, chlorotic lesions with occasional green islands on the leaves. Approximately 25% of the field had plants with these symptoms. The presence of the virus was confirmed with an IYSV-specific Agdia Flash kit. IYSV infection was confirmed by RT-PCR with primers specific to the nucleoprotein (N) gene of IYSV. Primers 465c: 5′-AGCAAAGTGAGAGGACCACC-3′ and IYSV-239f: 5′ TGAGCCCCAATCAAGACG3′ (3) were used as forward and reverse primers, respectively, using total nucleic acids eluted from FTA cards that were previously coated with freshly prepared sap extracts from field samples. Amplicons of approximately 240 bp were obtained from four symptomatic plants tested but not from healthy and water controls. The amplicons were cloned and sequenced. Consensus sequence was derived from three clones. Comparison with IYSV N gene sequences available in GenBank showed sequence identity of 95 to 99% confirming the identity of the virus as IYSV. To our knowledge, this is the first report of IYSV infecting onion in Indonesia. The finding in Java underscores the need for conducting surveys in Java as well as other onion-growing regions of Indonesia to gain a better understanding of its incidence, distribution, and potential impact. References: (1) D. H. Gent et al. Plant Dis. 88:446, 2004. (2) B. Mandal et al. Plant Dis. 96:468, 2012. (3) H. R. Pappu et al. Virus Res. 141:219, 2009. (4) K. S. Ravi et al. Plant Pathol. 55:288, 2006.


Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 377-377 ◽  
Author(s):  
S. W. Mullis ◽  
R. D. Gitaitis ◽  
C. Nischwitz ◽  
A. S. Csinos ◽  
Z. C. Rafael Mallaupoma ◽  
...  

Onions have become an important export crop for Peru during the last few years. The onions produced for export are primarily short-day onions and include Grano- or Granex-type sweet onions. The first of two growing seasons for onion in Peru occurs from February/March until September/October and the second occurs from September/October to December/January. Iris yellow spot virus (IYSV [family Bunyaviridae, genus Tospovirus]), primarily transmitted by onion thrips (Thrips tabaci), has been reported in many countries during recent years, including the United States (1,2). In South America, the virus was reported in Brazil during 1999 (3) and most recently in Chile during 2005 (4). During 2003, an investigation of necrotic lesions and dieback in onions grown near the towns of Supe and Ica, Peru led to the discovery of IYSV in this region. Of 25 samples of symptomatic plants collected from five different fields near Supe, 19 tested strongly positive and an additional three tested weakly positive for IYSV using double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) (Agdia Inc., Elkhart, IN). None of the samples tested positive for Tomato spotted wilt virus (TSWV). A number of onions with necrosis and dieback symptoms were also observed during 2004 and 2005. During September 2005, 25 plants with symptoms suspected to be caused by IYSV or TSWV in the Supe and Casma valleys were collected and screened for both viruses using DAS-ELISA. All plants screened were positive for IYSV. There was no serological indication of TSWV infection in these samples. The positive samples were blotted onto FTA cards (Whatman Inc., U.K.) to bind the viral RNA for preservation and processed according to the manufacturer's protocols. The presence of IYSV was verified by reverse transcription-polymerase chain reaction (RTPCR) using (5′-TCAGAAATCGAGAAACTT-3′) and (5′-TAATTATATCTATCTTTCTTGG-3′) as forward and reverse primers (1), respectively. The primers amplify the nucleocapsid (N) gene of IYSV, and the RT-PCR products from this reaction were analyzed with gel electrophoresis with an ethidium bromide stain in 0.8% agarose to verify the presence of this amplicon in the samples. Subsequent to the September 2005 sampling, 72 additional samples from regions in northern and southern Peru were analyzed in the same manner. The amplicons obtained were cloned, sequenced, and compared with known IYSV isolates for further verification. Onions have become a significant export crop for Peru, and more research is needed to determine the impact of IYSV on the Peruvian onion export crop. To our knowledge, this is the first report of IYSV in onion in Peru. References: (1) L. du Toit et al. Plant Dis. 88:222, 2004. (2) S. W. Mullis et al. Plant Dis. 88:1285, 2004. (3) L. Pozzer et al. Plant Dis. 83:345, 1999. (4) M. Rosales et al. Plant Dis. 89:1245, 2005.


Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 378-378 ◽  
Author(s):  
H. R. Pappu ◽  
B. C. Hellier ◽  
F. M. Dugan

The incidence of Iris yellow spot virus (IYSV) of genus Tospovirus, family Bunyaviridae in a commercial onion crop was first confirmed in Washington state during 2003 (1). First found in Adams County, IYSV has rapidly spread to all onion-producing counties in the state, affecting seed and bulb crops. The USDA-ARS Western Regional Plant Introduction Station (WRPIS) collects, maintains, and distributes various Allium (garlic and onion) accessions. As part of the regeneration process, accessions are grown under field conditions at the WRPIS farms in two locations: Pullman and Central Ferry, WA. Symptoms indicative of viral infection, now known to be caused by IYSV, first appeared in field-grown accessions in 1999. In June 2005, leaf and scape tissues were collected from WRPIS accessions of wild onions (Allium pskemense, A. vavilovii, and A. altaicum) in Central Ferry that had symptoms indicative of IYSV infection (2). IYSV infection was confirmed using enzyme-linked immunosorbent assay with a commercially available kit (Agdia Inc., Elkhart, IN). Virus infection was further verified using reverse transcription-polymerase chain reaction (RT-PCR) with primers derived from the small (S) RNA of IYSV. The primers flanked the IYSV N gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′). RT-PCR gave a PCR product of expected size (≈1.2 kb). The DNA amplicon was cloned and sequenced. Nucleotide sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The prevalence of the vector, onion thrips (Thrips tabaci), combined with the widespread incidence of IYSV in seed and bulb production areas of the state may have resulted in natural infection of wild relatives of cultivated onion. The potential role of wild Allium spp. in IYSV epidemiology remains to be determined. Information on the extent of IYSV infection of onion germplasm would be useful in identifying potential sources of host plant resistance to IYSV. References: (1) L. J. du Toit et al. Plant Dis. 88:222, 2004. (2) B. Hellier et al. APSnet Image of the Week. Online publication, iw000049.asp, 2004.


Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1359-1359 ◽  
Author(s):  
M. E. Miller ◽  
R. R. Saldana ◽  
M. C. Black ◽  
H. R. Pappu

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) has emerged as a potentially devastating and widespread virus of onion. IYSV was first reported in the United States from Idaho in 1993 and has since spread to many of the onion-producing areas (1). In South America, the most recent reports of the virus on onion were from Peru and Chile (2,4). In 2005, onion plants in Uvalde County, Texas exhibited necrotic lesions on leaves typical of IYSV and disease incidence approached 100% in some fields with yield loss and quality problems. Five of six plants tested were positive for IYSV with double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA; Agdia Inc., Elkhart, IN). In 2006, similar lesions were observed on onion plants in Uvalde County and approximately 400 km south in Hidalgo and Cameron counties. Infection points generally started as a single plant near the edge of fields and spread to plants in a 3- to 4-m area after 1 to 2 weeks. Early-season disease incidence was low in onions grown for bulbs and transplants, <10% in 2006. Disease incidence increased in some fields until the crop was harvested. Leaves of symptomatic plants were tested for IYSV and Tomato spotted wilt virus (TSWV) using DAS-ELISA, and 18 of 23 samples from the Hidalgo County area and 12 of 21 samples from the Uvalde County area were positive for IYSV. All samples tested for TSWV from these counties were negative. Virus infection in some ELISA-positive plants was verified by reverse transcription-polymerase chain reaction (RT-PCR) using primers derived from the small RNA of IYSV. The primers flanked the IYSV nucleocapsid (N) gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′ (3). RT-PCR gave a PCR product of expected size (approximately 1.2 kb). The DNA amplicon was cloned and sequenced (GenBank Accession No. DQ658242). Nucleotide sequence analysis confirmed the identity of the amplicon as that of IYSV N gene and sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The primary vector of IYSV, onion thrips (Thrips tabaci), is a widespread and destructive pest of onion in south Texas. The year-to-year incidence of IYSV and the severity of the disease will probably depend on the onion thrips population levels. Bulb yield reduction could be severe during years with high thrips populations. More research is needed to determine the impact of IYSV on bulb yield in Texas, the relationship between IYSV incidence and T. tabaci population levels, and oversummering hosts. To our knowledge, this is the first known report of IYSV in Texas. References: (1) D. H. Gent et al. Plant Dis. 88:446, 2004, (2) S. W. Mullis et al. Plant Dis. 90:377, 2006, (3) H. Pappu et al. Arch. Virol. 151:1015, 2006. (4) M. Rosales et al. Plant Dis. 89:1245, 2005.


Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 838-842 ◽  
Author(s):  
A. Kritzman ◽  
M. Lampel ◽  
B. Raccah ◽  
A. Gera

Iris yellow spot virus (IYSV), a new tospovirus associated with a disease in onion (Allium cepa) that is known to growers in Israel as “straw bleaching,” was identified and further characterized by host range, serology, electron microscopy, and molecular analysis of the nucleocapsid gene. The transmissibility of IYSV by Thrips tabaci and Frankliniella occidentalis was studied. IYSV was efficiently transmitted by T. tabaci from infected to healthy onion seedlings and leaf pieces. Two biotypes of F. occidentalis, collected from two different locations in Israel, failed to transmit the virus. Surveys to relate the incidence of thrips populations to that of IYSV were conducted in onion fields. They revealed that the onion thrips T. tabaci was the predominant thrips species, and that its incidence was strongly related to that of IYSV. Forty-five percent of the thrips population collected from IYSV-infected onion and garlic fields in Israel transmitted the virus. IYSV was not transmitted to onion seedlings from infected mother plants through the seed, and was not located in bulbs of infected plants.


Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 839-839 ◽  
Author(s):  
S. Bag ◽  
P. Rogers ◽  
R. Watson ◽  
H. R. Pappu

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) is an important constraint to onion bulb and seed production in several onion-growing regions of the United States (1,3). While garlic (Allium sativum) was reported to be infected with IYSV in Réunion Island (4), there have been no confirmed reports of natural infection of garlic in the United States. Garlic plants showing near-diamond-shaped lesions were found in August of 2008 in Marion County, Oregon. The 0.4046-ha (1-acre) field plot consisted of various true-seeded garlic varieties and was adjacent to three onion fields that showed IYSV symptoms. Symptoms were observed on 5% of the garlic plants with most of the symptomatic plants displaying small and diffuse straw-colored spots. Seven of these symptomatic plants were selected for testing. Of these, two showed characteristic diamond-shaped, elongated, straw-colored lesions on garlic scapes. However, the lesions were more diffuse with less-defined edges compared with the characteristic diamond-shaped lesions that are often associated with IYSV infection (1). All symptomatic plants were positive for IYSV by double-antibody sandwich-ELISA with a commercially available kit (Agdia Inc., Elkhart, IN). To verify IYSV infection, total nucleic acid extracts from the symptomatic parts of the leaves were prepared and tested for the presence of IYSV by reverse transcription (RT)-PCR with primers 5′-TAAAACAAACATTCAAACAA-3′ and 5′-CTCTTAAACACATTTAACAAGCAC-3′, which flank the nucleocapsid (N) gene coded by the small RNA of IYSV (2). An approximate 1.1-kb amplicon was obtained from all symptomatic plants and cloned and sequenced. Nucleotide sequence comparisons using BLAST showed that a consensus of three clones derived from the amplicon from garlic (No. FJ514257) was 85 to 99% identical with IYSV sequences available in GenBank (Nos. AF001387, AB180918, and AB286063), confirming the identity of IYSV. To our knowledge, this is the first report of natural infection of IYSV infection of garlic in the United States. Additional surveys and testing are needed to obtain a better understanding of IYSV incidence in garlic to evaluate its impact on garlic production. References: (1) D. Gent et al. Plant Dis. 90:1468, 2006. (2) H. R. Pappu et al. Arch. Virol. 151:1015, 2006. (3) H. R. Pappu et al. Virus Res. 141:219, 2009. (4) I. Robène-Soustrade et al. Plant Pathol. 55:288, 2006.


Author(s):  
Norma Ávila Alistac ◽  
Sergio Ramírez Rojas ◽  
Ángel Rebollar Alviter ◽  
Remigio Anastacio Guzmán Plazola

<p>El objetivo de la investigación fue identificar hospedantes alternos de <em>Iris yellow spot virus</em> (IYSV) y establecer el rango de hospedantes del putativo vector(es) en regiones productoras de cebolla (<em>Allium cepa</em>) de Morelos y Michoacán, México. En 10 localidades de ambos estados se muestrearon cultivos de cebolla y arvenses, en presencia y ausencia del cultivo. Las plantas de cebolla se analizaron por RT-PCR y las arvenses por DAS-ELISA. Las arvenses se identificaron a nivel especie, los trips colectados de las mismas se establecieron colonias para su identificación por PCR, con iniciadores específicos que amplifican un segmento del gen de citocromo oxidasa I (COI). Se analizaron e identificaron 295 arvenses agrupadas en 56 especies (23 familias), todas resultaron negativas para IYSV. Se detectaron trips en 75 arvenses agrupadas en 17 especies. Se analizaron 33 poblaciones de trips (22 de Morelos y 11 de Michoacán). La secuenciación indicó identidad con <em>Thrips tabaci</em> con una homología superior a 97 %. Las arvenses <em>Ricinus communis</em> y <em>Acalypha ostryifolia</em> registraron el mayor número de <em>T. tabaci</em>. En cebolla se confirmó la presencia de IYSV con RT-PCR en las 10 parcelas muestreadas. Este es el primer reporte de la presencia de IYSV en el estado de Michoacán.</p>


2018 ◽  
Vol 2 (6) ◽  
pp. 971-978
Author(s):  
Rodolfo Velásquez-Valle ◽  
Manuel Reveles-Hernández

El virus de la mancha amarilla del iris (IYSV) es la enfermedad viral de mayor importancia para los cultivos de ajo y cebolla en Zacatecas, México. A finales de mayo de 2010 se encontraron lesiones amarillentas en forma de diamante en hojas y tallo floral de plantas de cebolla en parcelas comerciales, localizados en los municipios de Loreto, Villa de Cos, Sain Alto, Villanueva, Calera de V. R. y Enrique Estrada pertenecientes al estado de Zacatecas. La prueba DAS-ELISA mostró resultados positivos para este virus en las muestras procedentes de diferentes municipios. Thrips tabaci el único vector conocido del IYSV se encontró en las parcelas comerciales muestreadas, aunque la presencia de Frankliniella occidentalis también fue reconocida en una parcela comercial de cebolla, cuyas muestras resultaron positivas a IYSV. No se encontró diferencia entre la altura, número de hojas, peso y diámetro de bulbo de plantas sin lesiones y aquellas con diferente número de lesiones de IYSV.


Author(s):  
Norma Ávila Alistac ◽  
Sergio Ramírez Rojas ◽  
Ángel Rebollar Alviter ◽  
Remigio Anastacio Guzmán Plazola

<p>El objetivo de la investigación fue identificar hospedantes alternos de <em>Iris yellow spot virus</em> (IYSV) y establecer el rango de hospedantes del putativo vector(es) en regiones productoras de cebolla (<em>Allium cepa</em>) de Morelos y Michoacán, México. En 10 localidades de ambos estados se muestrearon cultivos de cebolla y arvenses, en presencia y ausencia del cultivo. Las plantas de cebolla se analizaron por RT-PCR y las arvenses por DAS-ELISA. Las arvenses se identificaron a nivel especie, los trips colectados de las mismas se establecieron colonias para su identificación por PCR, con iniciadores específicos que amplifican un segmento del gen de citocromo oxidasa I (COI). Se analizaron e identificaron 295 arvenses agrupadas en 56 especies (23 familias), todas resultaron negativas para IYSV. Se detectaron trips en 75 arvenses agrupadas en 17 especies. Se analizaron 33 poblaciones de trips (22 de Morelos y 11 de Michoacán). La secuenciación indicó identidad con <em>Thrips tabaci</em> con una homología superior a 97 %. Las arvenses <em>Ricinus communis</em> y <em>Acalypha ostryifolia</em> registraron el mayor número de <em>T. tabaci</em>. En cebolla se confirmó la presencia de IYSV con RT-PCR en las 10 parcelas muestreadas. Este es el primer reporte de la presencia de IYSV en el estado de Michoacán.</p>


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