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Plant Disease: In Press
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First report of Tomato spotted wilt virus infection of chrysanthemum in India
Plant Disease "First Look" paper • http://dx.doi.org/10.1094/PDIS-01-15-0126-PDN • posted 03/16/2015 This paper has been peer reviewed and accepted for publication but has not yet been copyedited or proofread. The final published version may differ.
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P. Renukadevi*, K. Nagendran, S. Nakkeeran, G. Karthikeyan, M. Jawaharlal, D. Alice,
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V.G. Malathi, Center for Plant Protection Studies, Department of Plant Pathology, Tamil Nadu
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Agricultural University,Coimbatore-641 003, Tamil Nadu, India; and H.R. Pappu, Department
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of Plant Pathology, Washington State University, Pullman,WA99164-6430, USA
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*Corresponding author:
[email protected];
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A severe necrosis disease was noticed in chrysanthemum (Dendranthema grandiflora Tzvelev)
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plants grown in the Nilgiris district of Tamil Nadu state, India during August, 2013. The plants
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showed veinal necrosis and necrotic spots on leaves, browning of flower petals, malformed
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flowers and stem necrosis. In severe cases, extensive necrosis, complete drying and death of the
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plants were also observed. Disease incidence was estimated to be 30%. The virus was
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mechanically transmitted from chrysanthemum plants to cowpea (Vigna unguiculata, cv.C152)
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and pigweed (Trianthema portulacastrum). Inoculated plants produced local chlorotic concentric
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rings which later turned to necrotic spots six days post inoculation. Symptoms on cowpea
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resembled the lesions caused by tospoviruses (1& 4). Total RNA was extracted from the
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symptomatic cowpea and chrysanthemum plants and RT-PCR was performed using the tospovirus
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degenerate primers (5’CCTTTAACAGTDGAAACAT 3’;
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5’CATDGCRCAAGARTGRTARACAGA3’) (4) corresponding to the L protein gene of
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tospoviruses. An amplicon of approximately 750 bp (GenBank Accession number KJ013534)
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was amplified from the symptomatic samples which was sequenced. The sequence had 98%
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identity with the large RNA of Tomato spotted wilt virus (TSWV) (KC261950, KC261956,
Plant Disease "First Look" paper • http://dx.doi.org/10.1094/PDIS-01-15-0126-PDN • posted 03/16/2015 This paper has been peer reviewed and accepted for publication but has not yet been copyedited or proofread. The final published version may differ.
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KC261959, KC261962). RT-PCR was performed with two sets of primer pairs, one specific to the
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TSWV nucleocapsid (N) gene ( Fwd 5’CAAGCAATAAAGATAAAGAAAGC3’ and Rev
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5’AGCATATAACAACTTCTACGATC 3’), and the NSm gene (Fwd
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5’ACCTATTATACACTTTGCTAAGAA 3’and Rev 5’AATGCAAAATWRACAGAAATT 3’) of
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TSWV. The 870 bp and 1000 bp PCR products obtained respectively, for the N and NSm genes
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were sequenced. Sequences obtained (GeneBank Accession numbers for N gene-KJ494928; NSm
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gene - KJ494927) exhibited the highest nucleotide identity of 98% with the corresponding regions
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of TSWV isolates from different hosts and countries (GenBank accession numbers: for N gene-
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FR693048, KC494481, KC494495 and for NSm gene- HQ830188, HQ830185, HM015511).
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Following this finding, all plants were tested for TSWV using DAS ELISA and TSWV-specific
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antiserum (Agdia Inc., Elkhart, IN). ELISA results confirmed the sequence data. This would
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facilitate future testing of suspected plants by ELISA on a larger scale. While there are several
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tospoviruses known to infect economically important crops in India (1&2), TSWV is not known to
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occur (1). Earlier reports of TSWV infection of peanut were later found to be due to another
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distinct tospovirus, Peanut bud necrosis virus (3). Our finding of TSWV in a widely grown
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ornamental crop such as chrysanthemum is of great concern considering the wide host range of
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TSWV. Surveys to determine its incidence and thrips vectors involved needs to be undertaken.
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To our knowledge this is the first report of TSWV occurring in India.
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References:
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(1) B. Mandal, et al. Plant Dis. 96:468, 2012.
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(2) H.R. Pappu, et al. Virus Res. 141:219, 2009.
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(3). D.V.R. Reddy et al. Annal. Appl. Biol. 120: 279, 1992
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(4) I. Stanković, et al. Plant Dis 97:150, 2013.
