Division of Biotechnology, Indian Institute of Horticultural Research, Hessaraghatta, Bangalore-560089.
Abstracts of the papers presented at the 16th Annual Convention and International Symposium of Indian Virological Society on “Management of Vector-Borne Viruses” at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Hyderabad, India, February 7–10, 2006.
Watermelon bud necrosis virus (WBNV) belongs to the tospovirus group and is a very important virus threatening the commercial cultivation of this crop in several parts of the country. There is no known source of resistance to this virus either in the cultivated or in the wild species of this crop. Pathogen derived resistance has been shown to be a successful strategy to combat tospo viruses in crops such as tomato. A 512 bp 3’end of the nucleocapsid gene (n-gene) has been cloned into a plant expression vector. Watermelon cv Arka Manik seedlings were subjected to direct DNA uptake method of transformation through electroporation. A total of 583 T1 plants were raised. Genomic DNA was isolated from 216 plants and was analyzed by PCR for the presence of the transgene with primers flanking the cassette containing the promoter, n-gene and the terminator. One hundred and forty four plants gave bands of the expected size. Twenty seven PCR products were selected at random and were subjected to dot-blot analysis where the probe used was the n-gene fragment of WBNV. Twenty-one PCR products were positive. Ten plants, which were positive for presence of the transgene, were selected and challenged with viruliferous thrips collected from field infected watermelon plants. All plants showed complete resistance to WBNV. This is a first time report in the world for resistance to this virus in watermelon.
