ISHS Acta Horticulturae 431: Tospoviruses and Thrips of Floral and Vegetable Crops
DEVELOPING TRANSGENIC CROPS THAT ARE RESISTANT TO TOSPOVIRUSES |
| Authors: | D. Gonsalves, S.Z. Pang, C. Gonsalves, B. Xue, M. Yepes, F.J. Jan |
| Abstract:
This paper summarizes data published from our laboratory on the development of transgenic plants for resistance to tospoviruses. Transgenic tobacco, Nicotiana benthamiana, tomato, lettuce, and chrysanthemum that express translatable or nontranslatable forms of the nucleocapsid (N) gene of tomato spotted wilt virus (TSWV) were developed. Transgenic tobacco and N. benthamiana that expressed low levels of N protein were highly resistant to TSWV isolates, but they were susceptible to impatiens necrotic spot virus (INSV). However, plants that accumulated high levels of N protein were susceptible to TSWV but resistant to INSV. Apparently, two resistance mechanisms operated in these transgenic plants: RNA-mediated protection in low expressors that showed resistance to TSWV; and N protein-mediated protection in high expressors that showed resistance to INSV. Transgenic tomato plants that expressed the N gene of TSWV were resistant to TSWV isolates. Moreover, progenies of a cross between a TSWV-resistant transgenic tomato and a transgenic tomato resistant to cucumber mosaic virus (CMV) were resistant to both viruses. Infectivity tests with transgenic lettuce that expressed the N gene of TSWV confirmed our observations with transgenic tobacco and N. benthamiana; that is, low expressors were highly resistant and high expressors were susceptible. We efficiently transformed four cultivars of chrysanthemums with the N gene of TSWV using the biolistic approach. Important aspects of the protocol involved the use of explants and step wise selection with kanamycin. Results reported here provide optimism that transgenic plants will provide a useful way to control tospoviruses in economically important crops. | |
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