Molecular analysis of thrips diversity and thrips-transmittedIris yellow spot virus(Tospovirus: Bunyaviridae) from Pakistan

During a survey conducted in several different regions of Brazil, two unique tospoviruses were isolated and characterized, one from chrysanthemum and the other from zucchini. The chrysanthemum virus displayed a broad host range, whereas the virus from zucchini was restricted mainly to the family Cucurbitaceae. Double-antibody sandwich-enzyme-linked immunosorbent assay and western immunoblot analyses demonstrated that both viruses were serologically distinct from all reported tospovirus species including the recently proposed peanut yellow spot virus and iris yellow spot virus (IYSV) species. The nucleotide sequences of the nucleocapsid (N) genes of both viruses contain 780 nucleotides encoding for deduced proteins of 260 amino acids. The N proteins of these two viruses displayed amino acid sequence similarities with the previously described tospovirus species ranging from 20 to 75%, but they were more closely related to each other (80%). Based on the biological and molecular features, these viruses are proposed as two new tospovirus species, designated chrysanthemum stem necrosis virus (CSNV) and zucchini lethal chlorosis virus (ZLCV). With the identification of CSNV and ZLCV, in addition to tomato spotted wilt virus, groundnut ring spot virus, tomato chlorotic spot virus, and IYSV, Brazil harbors the broadest spectrum of tospovirus species reported.

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First Report of Iris yellow spot virus on Onion (Allium cepa) in Texas

Plant Disease ◽

10.1094/pd-90-1359b ◽

2006 ◽

Vol 90 (10) ◽

pp. 1359-1359 ◽

Cited By ~ 7

Author(s):

M. E. Miller ◽

R. R. Saldana ◽

M. C. Black ◽

H. R. Pappu

Keyword(s):

Disease Incidence ◽

Iris Yellow Spot Virus ◽

Yellow Spot ◽

N Gene ◽

Nucleotide Sequence Analysis ◽

Rt Pcr ◽

Onion Thrips ◽

Spot Virus ◽

Das Elisa ◽

Bulb Yield

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.

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Iris yellow spot virus in Onion Seed Crops in South Africa

Plant Disease ◽

10.1094/pdis-91-9-1203a ◽

2007 ◽

Vol 91 (9) ◽

pp. 1203-1203 ◽

Cited By ~ 6

Author(s):

L. J. du Toit ◽

J. T. Burger ◽

A. McLeod ◽

M. Engelbrecht ◽

A. Viljoen

Keyword(s):

South Africa ◽

Iris Yellow Spot Virus ◽

Yellow Spot ◽

Onion Bulb ◽

Western Cape ◽

Spot Virus ◽

Total Rna ◽

Onion Seed ◽

Seed Crops ◽

Np Gene

In December 2006, symptoms typical of iris yellow spot caused by Iris yellow spot virus (IYSV; genus Tospovirus, family Bunyaviridae) were observed on scapes (seed stalks) in an onion (Allium cepa L.) seed crop in the Klein Karoo of the Western Cape Province, South Africa. Symptoms included diamond-shaped chlorotic or necrotic lesions on the scapes, some of which had ‘green-islands’ with nested diamond-shaped lesions, as well as indistinct, circular to irregular, chlorotic or necrotic lesions of various sizes. At the time symptoms were observed, approximately 5% of the scapes had lodged as a result of extensive lesions resembling those caused by IYSV. The crop was 2 to 3 weeks from harvest. Symptomatic tissue from two plants (two samples from one plant and four samples from the other plant) was tested for IYSV by reverse-transcriptase (RT)-PCR. Total RNA was extracted from symptomatic scape tissue with the SV Total RNA Isolation System (Promega, Madison, WI) according to the manufacturer's instructions. First strand cDNA was synthesized with the RevertAid H Minus First Strand cDNA Synthesis kit (Fermentas Inc., Hanover, MD), followed by PCR amplification with primers IYSV-For (TGG YGG AGA TGY RGA TGT GGT) and IYSV-Rev (ATT YTT GGG TTT AGA AGA CTC ACC), which amplify the nucleocapsid (NP) gene of IYSV. An amplicon of expected size (approximately 750 bp) was observed for each of the symptomatic plants assayed and was sequenced. Comparison of the sequence (GenBank Accession No. EF579801) with GenBank sequences revealed 95% sequence identity with the NP gene of IYSV GenBank Accession No. EF419888, with eight amino acid differences. The known geographic distribution of IYSV in onion bulb or seed crops has increased rapidly in recent years in many areas of the world (1). To our knowledge, this is the first confirmation of IYSV in South Africa. Approximately 6,100 ha of onion bulb crops are grown annually in South Africa in the Western Cape, Kwazulu Natal, Limpopo, and Northern Cape provinces, and 600 ha of onion seed crops are grown primarily in the semi-arid regions of the Western Cape. Examination of an additional 10 onion seed crops in the Klein Karoo during January 2007 revealed the presence of iris yellow spot in three more crops at approximately 5% incidence in each crop. The four symptomatic crops had all been planted as bulb-to-seed crops, using vernalized bulbs produced on the same farm. This suggests that IYSV may have been disseminated into the seed crops on the vernalized bulbs, either as infected bulb tissue or in viruliferous thrips on the bulbs. Reference: (1) D. H. Gent et al. Plant Dis. 90:1468, 2006.

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First Report of Iris yellow spot virus on Onion and Leek in Western Oregon

Plant Disease ◽

10.1094/pdis-91-4-0468a ◽

2007 ◽

Vol 91 (4) ◽

pp. 468-468 ◽

Cited By ~ 5

Author(s):

D. H. Gent ◽

R. R. Martin ◽

C. M. Ocamb

Keyword(s):

United States ◽

Disease Incidence ◽

The United States ◽

Yellow Spot ◽

Onion Bulb ◽

Spot Virus ◽

First Report ◽

Seed Crop ◽

Onion Seed ◽

Seed Crops

Onion (Allium cepa) and leek (Allium porrum) are grown on approximately 600 ha in western Oregon annually for bulb and seed production. During July and August of 2006, surveys of onion bulb crops and onion and leek seed crops in western Oregon found plants with symptoms of elongated to diamond-shaped, straw-colored lesions characteristic of those caused by Iris yellow spot virus (IYSV) (1–4). Symptomatic plants were collected from fields of an onion bulb crop, an onion seed crop, and two leek seed crops located in Marion County. The onion bulb crop had been planted in the spring of 2006, and the onion and leek seed crops had been planted in the fall of 2005, all direct seeded. Cultivar names were not provided for proprietary purposes. Symptomatic plants in the onion bulb crop and leek seed crop generally were found near the borders of the field. Disease incidence was less than 5% and yield losses in these crops appeared to be negligible. In the onion seed crop, symptomatic plants were found throughout the field and disease incidence was approximately 20%. Approximately 1% of the onion plants in this field had large necrotic lesions that caused the seed stalks (scapes) to lodge. The presence of IYSV was confirmed from symptomatic leaves and scapes by ELISA (Agdia Inc., Elkhart, IN) using antiserum specific to IYSV. RNA was extracted from symptomatic areas of onion leaves and scapes, and a portion of the nucleocapsid gene was amplified by reverse transcription-PCR. The amplicons were sequenced and found to share more than 99% nucleotide and amino acid sequence identity with an onion isolate of IYSV from the Imperial Valley of California (GenBank Accession No. DQ233475). In the Pacific Northwest region of the United States, IYSV has been confirmed in the semi-arid regions of central Oregon (1), central Washington (2), and the Treasure Valley of eastern Oregon and southwest Idaho (3). To our knowledge, this is the first report of the disease on a host crop in the mild, maritime region west of the Cascade Mountain Range and the first report of IYSV on leek seed crops in the United States, which complements a simultaneous report of IYSV on commercial leek in Colorado. The presence of IYSV may have implications for the iris and other ornamental bulb industries in western Oregon and western Washington. This report underscores the need for further research to determine the impact of the disease on allium crops and other hosts and the development of effective management programs for IYSV and the vector, Thrips tabaci. References: (1) F. J. Crowe and H. R. Pappu. Plant Dis. 89:105, 2005. (2) L. J. du Toit et al. Plant Dis. 88:222, 2004. (3) J. M. Hall et al. Plant Dis. 77:952, 1993. (4) H. F. Schwartz et al. Plant Dis. 91:113, 2007.

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Variabilidad y síntomas causados por Iris yellow spot virus en Nicotiana benthamiana

Revista Mexicana de Fitopatología Mexican Journal of Phytopathology ◽

10.18781/r.mex.fit.1707-2 ◽

2017 ◽

Vol 35 (4) ◽

Author(s):

Katya Ornelas-Ocampo ◽

Daniel Leobardo Ochoa-Martínez ◽

Sergio Aranda-Ocampo ◽

Sergio Ramírez-Rojas ◽

Hernán García-Ruíz

Keyword(s):

Allium Cepa ◽

Nicotiana Benthamiana ◽

Iris Yellow Spot Virus ◽

Yellow Spot ◽

Spot Virus

En cultivos de cebolla Allium cepa del estado de Morelos, México, se observan síntomas típicos y severos asociados a Iris yellow spot virus (IYSV). En esta investigación se estudiaron las alteraciones que ocasionan los aislamientos de IYSV procedentes de síntomas típicos y severos en Nicotiana benthamiana, las diferencias en el gen N y su filogenia. Cuatro aislamientos típicos y cinco severos inoculados mecánicamente causaron infección sistémica. En cámara bioclimática los aislamientos severos ocasionaron mayor severidad de síntomas. La secuencia del gen N de ambos aislamientos tuvo 98-99% de identidad con la nucleoproteína de IYSV y no se observaron cambios en la secuencia de nucleótidos entre ellos. Ambos aislamientos se agruparon con el genotipo IYSVBR y tuvieron mayor similitud con los reportados en Canadá y Estados Unidos.

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Development of a sensitive Luminex xMAP-based microsphere immunoassay for specific detection of Iris yellow spot virus

Virology Journal ◽

10.1186/s12985-018-0952-4 ◽

2018 ◽

Vol 15 (1) ◽

Cited By ~ 2

Author(s):

Cui Yu ◽

Cuiyun Yang ◽

Shaoyi Song ◽

Zixiang Yu ◽

Xueping Zhou ◽

...

Keyword(s):

Iris Yellow Spot Virus ◽

Yellow Spot ◽

Specific Detection ◽

Spot Virus ◽

Microsphere Immunoassay

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Iris yellow spot virus. [Distribution map].

Distribution Maps of Plant Diseases ◽

10.1079/dmpd/20143156806 ◽

2014 ◽

Author(s):

Keyword(s):

New York ◽

Tamil Nadu ◽

Uttar Pradesh ◽

Iris Yellow Spot Virus ◽

Yellow Spot ◽

Allium Porrum ◽

Distribution Map ◽

Spot Virus ◽

South Wales ◽

Virus Distribution

Abstract A new distribution map is provided for Iris yellow spot virus. Bunyaviridae: Tospovirus. Hosts: Onion (Allium cepa), Dutch iris (Iris hollandica), leek (Allium porrum) and garlic (Allium sativum). Information is given on the geographical distribution in Europe (Austria, Bosnia-Hercegovina, France, Germany, Greece, Italy, Netherlands, Serbia, Slovenia, Spain, UK, England and Wales), Asia (India, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, Tamil Nadu, Uttar Pradesh, Indonesia, Java, Iran, Israel, Japan, Honshu, Kyushu, Pakistan, Sri Lanka and Tajikistan), Africa (Egypt, Kenya, Mauritius, Reunion, South Africa and Uganda), North America (Canada, Ontario, Mexico, USA, Arizona, California, Colorado, Georgia, Hawaii, Idaho, Michigan, Nevada, New Mexico, New York, Oregon, Pennsylvania, Texas, Utah and Washington), Central America and Caribbean (Guatemala), South America (Brazil, Pernambuco, Sao Paulo, Chile, Peru and Uruguay) and Oceania (Australia, New South Wales, Victoria, Western Australia and New Zealand).

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