Natural Infection by Tospoviruses of Cucurbitaceous and Fabaceous Vegetable Crops in India |
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Authors: | R K Jain S Bag K Umamaheswaran and B Mandal |
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Institution: | Authors' addresses: Unit of Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110 012, India;;Department of Plant Pathology, Kerala Agricultural University, Vellayani 695 522, India (correspondence to R. K. Jain. E-mail: ) |
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Abstract: | Natural infection of tospoviruses on three cucurbitaceous (Cucumis sativus, cucumber; Luffa acutangula, ridge gourd; Citrullus lanatus, watermelon) and three fabaceous (Vigna unguiculata, cowpea; Phaseolus vulgaris, French bean; Dolichos lablab, sem) vegetable crops in India was identified on the basis of nucleocapsid protein (NP) gene characteristics. The complete NP gene of the cowpea isolate from Kerala and the sem isolate from Tamil Nadu was 831 nucleotides long, encoding a protein of 276 amino acids. For other Tospovirus isolates from cucumber, French bean, ridge gourd and watermelon, the partial NP gene (291 nt) was sequenced. Comparative NP gene sequence analyses revealed that fabaceous isolates shared maximum identity both at the nucleotide (92–97%) and amino acid (93–97%) levels with the corresponding region of Groundnut bud necrosis virus (GBNV), whereas cucurbitaceous isolates shared maximum identity both at nucleotide (93–99%) and amino acid (95–98%) levels with the corresponding region of Watermelon bud necrosis virus (WBNV), results suggesting that the Tospovirus isolates infecting fabaceous hosts should be regarded as strain of GBNV, whereas those infecting cucurbitaceous hosts as a strain of WBNV. Nucleocapsid protein gene was conserved both in GBNV and WBNV isolates originating from different hosts and locations. |
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Keywords: | Tospovirus nucleocapsid protein gene Groundnut bud necrosis virus Watermelon bud necrosis virus fabaceous hosts cucurbitaceous hosts India |
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