POSITIVE AND NEGATIVE SENSE COAT PROTEIN GENE-MEDIATED PROTECTION AGAINST POPLAR MOSAIC CARLAVIRUS IN NICOTIANA-BENTHAMIANA

Plants of Nicotiana benthamiana were transformed with four constructs based on the coat protein gene of a poplar mosaic carlavirus (PMV) iso late from the UK. The four constructs were: the capsid protein coding sequence plus a portion of the adjacent sequence encoding a protein wi th a molecular mass of 14 kDa (CP14k); the capsid protein coding seque nce in the positive sense (CPP); a mutated capsid protein coding seque nce (CPM) and the capsid protein coding sequence in the negative sense (CPN). Forty-one regenerated plants, after selection for their kanamy cin resistance, were confirmed by PCR to contain the appropriate seque nces. Virus coat protein was detected in small amounts in 50% of the p lants transformed with the CP14k or CPP constructs. Primary transforma nts showed a range of reactions to challenge with two isolates of PMV. These varied from apparently no infection in inoculated or in later-f ormed young leaves, as assessed by ELISA, to typical systemic symptoms associated with large amounts of serologically detected virus. There was no correlation between the level of protection against virus infec tion and the observed accumulation of transgene protein product. Plant s were protected whether transformed with the coat protein coding sequ ence in the positive or negative sense.