Occurrence of Impatiens necrotic spot virus and Tomato spotted wilt virus on Potatoes in Iran.

There have been an increasing number of records of the natural infection of various crops and ornamentals in Iran with Impatiens necrotic spot virus (INSV), Tomato spotted wilt virus (TSWV), and Tomato yellow fruit ring virus (TYFRV), a recently proposed species in the genus Topovirus (3). TYFRV, originally believed to be TSWV and named as such, has been previously reported to occur in Iranian potato fields (2). During the growing seasons of 2004 to 2006, surveys were conducted in potato fields in different potato-producing (Solanum tuberosum) provinces of Iran (Ardabil, Azarbayejan-e-sharqi, Chaharmahal-va-bakhtiyari, Esfahan, Hamedan, Kerman, Khorasan, Khuzestan, Lorestan, Tehran, Qazvin, and Zanjan) to detect the presence of Tospovirus spp. infecting this crop, including Groundnut ringspot virus (GRSV), INSV, Iris yellow spot virus (IYSV), Tomato chlorotic spot virus (TCSV), TSWV, TYFRV, and Watermelon silver mottle virus (WSMoV). Overall, 186 fields were surveyed, and 2,823 potato leaf samples from plants showing tospovirus-like symptoms of chlorotic or necrotic spots, chlorosis, and necrosis were collected before or through the flowering stage, approximately 50 to 90 days after planting. Each leaf sample was tested by double-antibody sandwich (DAS)-ELISA using specific antisera (Bioreba, Reinach, Switzerland; Loewe, Sauerlach, Germany; DSMZ, Braunschweig, Germany) for the presence of the aforementioned tospoviruses. TYFRV, TSWV, and INSV were found in 24.0, 4.1, and 0.4% of the samples collected from 133, 51, and 7 fields surveyed, respectively. None of the samples had a positive reaction in ELISA to GRSV, IYSV, TCSV, and WSMoV. To confirm this testing, a number of the leaf samples that were found to be positive for INSV, TSWV, and TYFRV in ELISA tests were mechanically inoculated on Petunia × hybrid and Nicotiana benthamiana; the inoculated plants showed typical necrotic local lesions of tospoviruses and chlorotic or necrotic spots followed by systemic infection, respectively; their infection was subsequently confirmed by ELISA. The samples also were tested by reverse transcription-PCR technique using previously described specific primers (1,4). The PCR reaction resulted in the specific amplification of a 0.59-, 0.71-, and 0.67-kb (or 1.2-kb) fragment of INSV, TSWV, and TYFRV RNAs, respectively. This study showed that tospoviruses, especially TYFRV, are widespread in Iranian potato fields. It is hoped that the results may help us to improve a seed potato certification program in the future. To our knowledge, this is the first report of INSV and TSWV from potatoes in Iran. References: (1) A. R. Golnaraghi et al. Plant Dis. 92:1280, 2008. (2) R. Pourrahim et al. Plant Dis. 84:442, 2001. (3) S. Winter et al. Plant Pathol. 55:287, 2006. (4) H. Uga and S. Tsuda. Phytopathology 95:166, 2005.

Detection and Characterization of a Distinct Isolate of Tomato yellow fruit ring virus from Potato.

A distinct isolate (TY-PF36) of Tomato yellow fruit ring virus (TYFRV) was obtained from potato (Solanum tuberosum) in Iran. Chlorosis and necrotic spots on leaves associated with leaf and stem necrosis symptoms appear on the affected plants. Of 32 plant species and cultivars mechanically inoculated, 24 were susceptible to the virus isolate. The isolate strongly reacted with TYFRV antibodies in enzyme-linked immunosorbent assay (ELISA), but not with the specific antibodies of other tospoviruses tested. TYFRV-specific N gene primers described previously, however, failed to produce DNA fragments from the total RNA extracts of the infected plants in reverse transcription-polymerase chain reaction (RT-PCR). Nucleotide sequencing of the complete N gene and partial L gene of this isolate revealed considerable differences to those reported for TYFRV with identities ranging from 83.9 to 84.2% and 84.9 to 85.4%, respectively. Two specific primers were designed for detecting TY-PF36 using RT-PCR; TY-PF36 was detected in symptomatic field samples of potato, peanut, soybean, and two weed species, Datura metel and D. stramonium.

Incidence and Distribution of Important Viral Pathogens in Some Iranian Potato Fields.

From a total of 8,135 potato leaves collected from 132 fields in 11 provinces of Iran, the incidence and distribution of Alfalfa mosaic virus (AlMV), Eggplant mottled dwarf virus (EMDV), Potato leafroll virus (PLRV), Potato virus A (PVA), Potato virus M (PVM), Potato virus S(PVS), Potato virus X (PVX), Potato virus Y (PVY), and Tomato yellow fruit ring virus (TYFRV) were assessed using serological and biological methods. Based on enzyme-linked immunosorbent assay (ELISA) results, viruses in decreasing order of incidence in potato were PVS (35.9%), PVY (34.4%), PVA (27.0%), PVX (20.8%), PLRV (13.9%), PVM (9.0%), AlMV (7.0%), TYFRV (5.9%), and EMDV (5.1%). All 132 fields surveyed had some degree of virus infection, ranging from 28.8 to 98.6%, with an overall incidence of 75.2%. The highest and lowest incidence of virus infections among the surveyed provinces occurred in Kerman (93.2%) and Ardabil (56.7%), respectively. Overall, 25.0 and 50.2% of the collected potato samples had single or mixed infections, respectively. High levels of mixed infections were found between PVX and PVS (8.6%), and PVX and PVY (7.6%). Moreover, co-infection of samples with PVS and PVY, PVA and PVS, and PVA and PVY, the aphid-vectored virus/virus combinations, occurred at the highest incidence in almost all provinces surveyed, 15.3, 13.8, and 12.8%, respectively. In this study, Beet curly top virus was detected in symptomatic potato samples collected from some fields in the Kermanshah province.

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.

First Report of Beet virus Q on Sugar Beet in Iran.

During the 2001 growing season, a survey was conducted to determine the incidence of Beet necrotic yellow vein virus (BNYVV), Beet soilborne virus (BSBV), and Beet virus Q (BVQ) in Iran. A total of 2,816 random and 76 samples with rhizomania were collected from 131 fields in the main sugar beet cultivation areas of 13 provinces in Iran. All samples were tested using a tissue-blot immunoassay (TBIA) with commercial BNYVV (As-0799.1/CG6-F4), BSBV (As-0576.1), and BSBV/BVQ (As-0576.2) antisera provided by S. Winter (DSMZ, Braunschweig, Germany). For randomly collected samples, the highest incidence of virus infection was found for BNYVV (52.3%), followed by BSBV (9.5%) and BVQ (1.5%). Co-infection of BNYVV with BSBV or BVQ was 6.6% and 0.9%, respectively. Infection with both BSBV and BVQ was found in 16 (0.6%) samples. In addition, 0.4% (12) of the samples was infected with all three viruses. Our results indicated the presence of BVQ in samples from 10 fields located in Azarbayejan-e-gharbi, Esfahan, Fars, Kermanshah, Khorasan, Lorestan, and Semnan provinces of Iran, with or without rhizomania-like symptoms. The presence of viruses was confirmed using reverse transcription-polymerase chain reaction (RT-PCR) of RNA from 81, 19, and 14 root samples with positive reaction in TBIA to BNYVV, BSBV, and BVQ, respectively, with previously described primers (3,4). The primers specifically amplified fragments of 501 bp, 602 bp, 399 bp, and 291 bp of the BNYVV RNAs 1 and 4, BSBV RNA-2, and BVQ RNA-1, respectively. Our results indicated that the samples tested were also positive using RT-PCR. The putative vector for BNYVV, BSBV, and BVQ, Polymyxa betae, was also detected in 161 samples (from 127 fields) by amplification of a 170-bp fragment of the P. betae repetitive EcoRI-like fragments using previously described primers (4). RT-PCR products from 72 BNYVV-positive sugar beet root samples from 58 fields that also gave positive reactions in TBIA were analyzed using single-strand conformation polymorphism (SSCP) as previously described with extracts from root beards of the susceptible sugar beet cvs. OPUS and IC1 grown in the soils infested with BNYVV types A and B (provided by A. Meunier, Unite de Phytopathologie-UCL-AGRO-BAPA, Louvain-la-Neuve, Belgium) as positive controls (3). The patterns obtained with SSCP were uniform and showed widespread occurrence of BNYVV type A in almost all provinces surveyed. The fragments obtained for BNYVV RNAs 1 and 4 of an isolate from Qazvin (BNQ1) were sequenced (GenBank Accession Nos. AY703452 and AY703455) and compared with other sequences available in GenBank using Clustal W, which revealed 99.3 and 99.6% identity with the Japanese S (D84410) and Italian type A (AF197552) isolates, respectively. The economic importance of BVQ and its interactions with other sugar beet soilborne viruses remains a matter of debate. BNYVV and BSBV have been previously reported from Iran (1,2). To our knowledge, this is the first report of the natural occurrence of BVQ in sugar beets in Iran. References: (1) Sh. Farzadfar et al. Plant Dis. 86:187, 2002. (2) K. Izadpanah et al. Iran. J. Plant Pathol. 32:155, 1996. (3) R. Koenig et al. J. Gen. Virol. 76:2051, 1995. (4) A. Meunier et al. Appl. Environ. Microbiol. 69:2356, 2003.

Reservoir Weed Hosts for Turnip mosaic virus in Iran.

During the summer of 2003, weed samples of Rapistrum rugosum and Sisymbrium loeselii showing severe mosaic, malformation, and stunting were collected from cauliflower fields in Tehran Province of Iran. Using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with specific polyclonal antibodies, the samples were tested for the presence of Beet western yellows virus, Cauliflower mosaic virus, Radish mosaic virus, Turnip crinkle virus, Turnip mosaic virus (TuMV) (DSMZ, Braunschweig, Germany), Cucumber mosaic virus, and Tobacco mosaic virus (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France). Leaf extracts were used for mechanical inoculation and they produced chlorotic local lesions on Chenopodium amaranticolor, necrotic lesions on leaves and shoot apex necrosis on Nicotiana glutinosa, leaf deformation, mosaic, and stunting on Petunia hybrida, and severe mosaic, distortion, and stunting on Brassica rapa. These symptoms were similar to those that were described previously for TuMV (4). ELISA results showed that the original leaf samples and inoculated indicator plants reacted positively with TuMV antibodies, but not with antibodies for any of the other viruses listed above. Also, reverse transcription-polymerase chain reaction of total RNA extracted from the collected leaf samples using the universal primers for potyviruses (3) resulted in the amplification of two fragments of the expected sizes, approximately 700 and 1,700 bp. TuMV, a member of the genus Potyvirus in the family Potyviridae, is transmitted by aphids in a nonpersistent manner (4). This virus is geographically widespread with a wide host range that can infect 318 species in 156 genera of 43 plant families including, Brassicaceae, Chenopodiaceae, Asteraceae, Cucurbitaceae, and Solanaceae (2,4). R. rugosum and S. loeselii, two annual or biennial plants in the Brassicaceae family, were common and widely distributed in the fields surveyed. The presence of TuMV-infected weed hosts in cauliflower fields may impact disease management strategies. TuMV was first observed on stock plants (Matthiola sp.) in Iran (1). To our knowledge, this is the first report of natural occurrence of TuMV on weed hosts in Iran. References: (1) M. Bahar et al. Iran. J. Plant Pathol. 21:11, 1985. (2) J. R. Edwardson and R. G. Christie. The potyvirus group. Fla. Agric. Exp. Stn. Monogr. Ser. No. 16, 1991. (3) A. Gibbs and A. Mackenzie. J. Virol. Methods 63:9, 1997. (4) J. A. Tomlinson. Turnip mosaic virus. No. 8 in: Descriptions of Plant Viruses. CMI/AAB, Surrey, England, 1970.

Occurrence and Relative Incidence of Viruses Infecting Soybeans in Iran.

A survey was conducted to determine the incidence of Alfalfa mosaic virus (AlMV), Bean common mosaic virus (BCMV), Bean yellow mosaic virus (BYMV), Blackeye cowpea mosaic virus (BlCMV), Cucumber mosaic virus (CMV), Pea enation mosaic virus (PEMV), Peanut mottle virus (PeMoV), Soybean mosaic virus (SMV), Tobacco mosaic virus (TMV), Tobacco ringspot virus (TRSV), Tobacco streak virus (TSV), Tomato ringspot virus (ToRSV), and Tomato spotted wilt virus (TSWV) on soybean (Glycine max) in Iran. Totals of 3,110 random and 1,225 symptomatic leaf samples were collected during the summers of 1999 and 2000 in five provinces of Iran, where commercial soybean is grown, and tested by enzyme-linked immunosorbent assay (ELISA) using specific polyclonal antibodies. Serological diagnoses were confirmed by electron microscopy and host range studies. The highest virus incidence among the surveyed provinces was recorded in Mazandaran (18.6%), followed by Golestan (15.7%), Khuzestan (14.2%), Ardabil (13.9%), and Lorestan (13.5%). Incidence of viruses in decreasing order was SMV (13.3%), TSWV (5.4%), TRSV (4.2%), TSV (4.1%), PEMV (2.9%), BYMV (2.2%), ToRSV (2.1%), AlMV (1.3%), BCMV (0.8%), and CMV (0.6%). Additionally, 1.5% of collected leaf samples had positive reactions in ELISA with antiserum to TMV, indicating the possible infection of soybeans in Iran with a Tobamovirus that is related serologically to TMV. Of 195 leaves from plants showing soybean pod set failure syndrome (PSF) in Mazandaran and Lorestan, only 14 (7.2%) samples had viral infection. No correlation was observed between PSF and presence of the 13 viruses tested, suggesting the involvement of other viruses or factors in this syndrome. To investigate the presence of seed-borne viruses, including SMV, TRSV, ToRSV, and TSV, 7,830 soybean seeds were collected randomly at harvesting time from the major sites of soybean seed production located in Mazandaran and Golestan provinces. According to ELISA analyses of germinated seedlings, 7.1 and 8.9% of the seed samples from Golestan and Mazandaran provinces, respectively, transmitted either SMV, TRSV, ToRSV, or TSV through seed. We also showed that SMV and other seed transmissible viruses, as well as TSWV, usually are the most prevalent viruses in soybean fields in Iran. In this survey, natural occurrence of AlMV, BCMV, BlCMV, BYMV, CMV, PEMV, PeMoV, and TSWV was reported for the first time on soybeans in Iran.

Occurrence of Arabis mosaic virus and Grapevine leaf roll associated virus-3 on Grapevines in Iran.

During 2001, a survey was conducted in vineyards in northwestern Iran and the eastern and western provinces of Azarbaijan, Zanjan, and Qazvin to detect the presence of Arabis mosaic virus (ArMV) and Grapevine leaf roll associated virus-3 (GLRaV-3). From December 2001 through March 2002, 5,352 dormant stem cuttings were collected. A portion of all stem cuttings was callused, rooted, potted, and grown in a greenhouse. Each sample was tested for the presence of ArMV and GLRaV-3 with specific antisera (Bioreba, Basel, Switzerland). Extracts of bark scrapings were prepared from the remaining portion of the dormant cuttings. After bud break of rooted cuttings, leaf extracts were prepared by the method used by Rowhani et al. (2). Dormant bark and leaf extracts were used with double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Among the samples tested, ArMV and GLRaV-3 were found in 4.7 and 2.3% of the collection, respectively. Leaf extracts that had tested positive for ArMV using ELISA, were mechanically inoculated on the indicator host plants of Chenopodium amaranticolor, Cucumis sativus, and Petunia × hybrida. All plants developed local lesions that subsequently developed systemic chlorosis that is reported for ArMV. Biological assays confirmed the results of ArMV using ELISA. To confirm testing, a number of the samples that were found positive for GLRaV-3 in ELISA tests were tested by reverse transcription-polymerase chain reaction (RT-PCR) technique using previously described specific primers (1). The PCR reaction resulted in the specifically amplification of a 300-bp fragment of GLRaV-3 RNA. In cvs. White Keshmesh, Ghezel Ozum, Red Lal, Askari, and Red Kehsmesh, symptoms associated with GLRaV-3 were reduced growth with smaller leaves and shoots. By late summer, the leaves rolled downward and the interveinal areas of the leaves turned to red, while the principal veins remained green in cvs. Red Lal and Red Keshmesh. Symptoms associated with ArMV were reduced growth, shoots with short internodes, and leaf chlorosis and distortion. To our knowledge, this is the first report of ArMV and GLRaV-3 from grapevines in Iran. References: (1) A. Nassuth et al. J. Virol. Methods 90:37, 2000. (2) A. Rowhani et al. Plant Dis. 81:799, 1997.

First Report of Papaya ringspot virus on Papaya in Iran.

Papaya, a popular fruit crop native to the American tropics, was introduced to the southern tropical provinces of Iran in the 1990s and its cultivation is widely increasing in these areas. During April 2000, severe leaf distortion and mottling were observed on papaya trees (Carica papaya) in Hormozgan Province in southern Iran. Affected trees were stunted and yielded less fruit. Samples of papaya leaf extracts (1:10 wt/vol) in 0.01 M potassium phosphate buffer (pH 7.0) were mechanically inoculated on indicator host plants, causing local lesions on Chenopodium amaranticolor and C. quinoa and chlorotic spots followed by systemic mosaic symptoms on Cucurbita pepo. Papaya ringspot virus (PRSV) was detected in the leaf samples of papaya plants and the inoculated Cucurbita pepo plants using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with PRSV-specific antisera (polyclonal antibody AS-0086 and PV-0244, DSMZ, Braunschweig, Germany). PRSV causes one of the most destructive diseases of papaya worldwide (1). PRSV has been previously reported from Citrullus vulgaris and Cucumis melo from Iran as Watermelon mosaic virus 1 (2), but to our knowledge, this is the first report of occurrence of PRSV on papaya in Iran. References: (1) D. E. Purcifull et al. Papaya ringspot virus. No. 292. CMI/AAB, Surrey, England, 1984. (2) F. Ebrahim-Nesbat. Phytopathol. Z. 79:352, 1974.

First Report of Groundnut bud necrosis virus in Iran.

During the summer of 2001, mosaic, mottle, ring mosaic, stunting, and bud necrosis were observed in peanut fields (Arachis hypogaea cv. Gilan) in the Golestan Province of Iran. Mechanical inoculation of these samples caused necrotic local lesions on Vigna unguiculata cv. Mashad, necrosis on Nicotiana benthamiana and N. rustica, and mosaic followed by bud necrosis on Arachis hypogaea cv. NC2. Using triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) and polyclonal (As) combined with monoclonal antibodies (MAbs) produced by DSMZ (Braunschweig, Germany), the samples were tested for presence of impatiens necrotic spot virus (INSV) (As-0115, MAb-0117-5E4), tomato spotted wilt virus (TSWV) (As-0105, MAb-0116-2B6, MAb-0106-4F2), and groundnut bud necrosis virus (GBNV) (As-0118, MAb-0226-1B4). The samples also were checked by TSWV polyclonal antibody (As-0526, As-0580, DSMZ). ELISA results showed leaf samples and inoculated indicator plants reacted positively to GBNV antibodies. Also a weak reaction was observed with TSWV-polyclonal antibody. However no reaction was detected using the INSV and TSWV-MAbs. GBNV is a member of the Tospovirus genus and has serological relationship with TSWV (1). To our knowledge, this is the first report of GBNV occurrence in Iran. Reference: (1) C. Heinze et al. Phytopathology 85:683-690, 1995.

First Report of Beet soil-borne virus on Sugar Beet in Iran.

Sugar beet is a main field crop in Iran and is cultivated in 186,000 ha. During the summer of 2001, sugar beet (Beta vulgaris) plants with pale, often upright, narrow, and rolled leaves were collected from the six main beet cultivation provinces of Iran (Fars, Ghazvin, Kermanshah, Khorasan, Semnan, and Isfahan). Roots of symptomatic plants were small, often with constriction, and exhibited warty outgrowth, proliferation of fibrous roots, and vascular necrosis. Beet soil-borne virus (BSBV) and Beet necrotic yellow vein (BNYVV, genus Benyvirus) were detected in sugar beet root samples by tissue-blot immunoassay (TBIA) using BSBV- and BNYVV-specific monoclonal antibodies (As-0576.1 and As-0799.1/CG6-F4, respectively; DSMZ Plant Virus Collection, Germany). Root extracts of sugar beet plants infected with BSBV, were infective by mechanical inoculation to Chenopodium quinoa causing necrotic ring spots. BSBV was detected in inoculated plants by TBIA. Laboratory tests using TBIA on 2,387 randomly collected samples showed that BSBV was present in 406 plants (17%) and BNYVV was present in 1,347 plants (56.43%). BSBV resembles BNYVV, the causal agent of sugar beet rhizomania, morphologically and in its transmission by Polymyxa betae (1). BNYVV has been reported previously from Iran (2). To our knowledge, this is the first report of BSBV occurring on sugar beet in Iran. References: (1) M. Ivanovic and I. Macfarlane. Annu. Rep. Rothamsted Exp. Stn. Page 190, 1982. (2) K. Izadpanah et al. Iran. J. Plant Pathol. 32:155, 1996.

First Report of Tomato Spotted Wilt Virus on Potatoes in Iran.

Severe leaf and stem necrosis before flowering was observed in potato (Solanum tuberosum) fields of Firouzkoh Province, Iran, during the summer of 1998. Infected plants died before the end of the growing season. Necrosis was more severe in cv. Agria than in cvs. Ajaxs and Arinda. A high population of Thrips tabaci was observed in August and September. Tomato spotted wilt virus (TSWV) (1) was detected in affected potatoes by using specific TSWV-IgG (from Bioreba) in double-antibody sandwich enzyme linked immunosorbent assay and by indicator plant reactions. Mechanical inoculation of indicator plants with leaf extracts of symptomatic potatoes produce necrotic local lesions in Chenopodium quinoa, C. amaranticolor, Gomphrena globosa, Vicia faba, Vigna sinensis, Phaseolus aureus var. Gohar, P. vulgaris, and Petunia hybrida. The virus caused systemic necrosis in Capsicum frutescens, Datura stramonium, D. metel, Nicotiana glutinosa, N. rustica, and Trapaeolum majus, preceded by systemic chlorotic spots. TSWV was reported from ornamental crops in Tehran and Absard areas near to Firouzkoh province (2), but this is the first report of TSWV occurrence on potatoes in Iran. References: (1) T. S. Ie. Descriptions of Plant Viruses. No. 39, 1970. (2) A. A. Moeini, et al. Iran. J. Plant Pathol. (In press.).

First Report of a Tospovirus Infection of Peanuts in Iran.

During the summer of 2000, severe stunting, mosaic, bud necrosis, and chlorosis symptoms were observed on peanut (Arachis hypogaea cv. Gilan) plants growing in fields in the Golestan Province of Iran. Leaf extracts of peanut plants were infective (mechanical inoculation) causing necrotic local lesions on Chenopodium quinoa, C. amaranticolor, Gomphrena globosa, Phaseolus vulgaris cv. Talash, Vicia faba, and Vigna unguiculata cv. Mashad; systemic chlorotic spots were followed by systemic necrosis in Datura stramonium, D. metel, and Nicotiana rustica; chlorotic and necrotic spots were followed by top necrosis in Glycine max. About 2 weeks after inoculation, the chlorosis followed by stunting and bud necrosis observed in the field were reproduced in A. hypogaea cv. Gilan. Tomato spotted wilt virus (TSWV) was detected in the original peanut plants and in plant species that developed symptoms after inoculation with extracts from peanut plants, when analyzed by double-antibody sandwich enzyme-linked immunosorbent assay using TSWV-specific antisera (polyclonal antibody As-0526 and As-0580, DSMZ, Braunschweig, Germany). TSWV is one of the most important viruses in the world (2) and has been reported on potato (3) and tomato (1) in Iran. To our knowledge, this is the first report of TSWV infection of peanut in Iran. References: (1) K. Bananej et al. Iran. J. Plant Pathol. 34:30, 1998. (2) R. A. Mumford et al. Ann. Appl. Biol. 128:159, 1996. (3) R. Pourrahim et al. Plant Dis. 85:442, 2001.

First Report of Tomato spotted wilt virus on Soybean in Iran.

During the summers of 1999 and 2000, 3,110 soybean (Glycine max) leaf samples were randomly collected from soybean fields in the Ardebil, Goletan, Khuzestan, Lorestan, and Mazandaran provinces of Iran. Tomato spotted wilt virus (TSWV) was detected in leaf samples by TSWV-specific polyclonal antibody (As-0526 and As-0580, DSMZ, Braunschweig, Germany) in double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Mechanical inoculation of 26 plant species (10 plants per species) and cultivars with extracts of positive leaf samples produced necrotic local lesions in Beta vulgaris, Chenopodium quinoa, C. amaranticolor, Gomphrena globosa, Phaseolus vulgaris cv. Talash, Vicia faba, and Vigna unguiculata cv. Mashad; produced systemic chlorosis followed by necrosis in Datura stramonium, D. metel, Nicotiana rustica, N. tabacum cv. Samsun, N. glutinosa, N. bentamiana, and Glycine max cv. Hill; and produced chlorosis, stunting, and bud necrosis in Arachis hypogaea (peanut). Plants developing these symptoms following mechanical inoculation with extracts from original soybean leaves were positive in ELISA for TSWV. ELISA results indicate that the overall incidence of TSWV on soybean in the five provinces was 5.4%. TSWV has been reported in potato (2) and tomato (1) from Iran, but to our knowledge, this is the first report of the occurrence of TSWV on soybean in Iran. References: (1) K. Bananej et al. Iran. J. Plant Pathol. 34:30, 1998. (2) R. Pourrahim et al. Plant Dis. 85:442, 2001.