Evaluation of transgenic 'Xanthi' tobacco and development of transgenic 'Burley' tobacco containing the soybean mosaic virus coat protein gene

Coat protein mediated protection results in delay of symptoms and lower virus concentration within tobacco plants. In this study, plants of two transgenic Nicotiana tabacum cv. ‘Xanthi’ lines expressing the soybean mosaic virus coat protein (SMV-CP) were inoculated with four potyviruses: potato virus Y (PVY), tobacco vein mottling virus (TVMV), tobacco vein banding mosaic virus (TVBMV), and tobacco etch virus (TEV). Protection varied from no delay in disease development to protection for up to 20 days. Xanthi was determined not to be a good host for TVMV since controls became only mildly infected. With PVY there was no delay in disease development seen in either of the transgenic tobacco lines. Symptom expression was moderately lessened with challenge of TVBMV, however virus accumulation was decreased only slightly. Strong protection was observed with TEV for 20 days in both transgenic lines. The type of protection shown with TEV would be highly desirable in an economic cultivar of tobacco. Therefore, binary vector pBI2-21B carrying the SMV-CP gene was used to transform several lines of Nicotiana tabacum cv. ‘Burley’. Transformation of tobacco was via Agrobacterium tumefaciens carrying pBI2-21B and plants regenerated by standard tissue culture methods. Transformed tobaccos were identified during the R₀ generation using Protein A Sandwich-ELISA, PGR, and Southern blot analysis. These techniques preliminarily allow for early identification of transformed plants.