Tobacco plants transformed with a modified coat protein of tomato mottle begomovirus show resistance to virus infection

Tobacco plants (Nicotiana tabacum 'Xanthi') were transformed with a binary vector containing the coat protein gene of tomato mottle begomovirus (ToMoV ) modified by the deletion of 30 nucleotides in the 5' end. The R-1 generat ion was screened for resistance to ToMoV by inoculation with viruliferous w hiteflies. Fifteen days after inoculation, symptom development was recorded weekly for up to 120 days using a visual scale, and ToMoV infection was co nfirmed by polymerase chain reaction and enzyme-linked immunosorbent assay. The response to high inoculation levels of ToMoV varied and ranged from su sceptibility to immunity. The transgene transcript was detected by northern blot analysis; however, the transgene product could not be detected by pro tein blot analysis using antisera reactive with ToMoV coat protein. The lac k of detection of the transgene product in resistant plants suggests that i t is not involved in eliciting the resistance response and that resistance may be mediated by the transgene transcript.