NICOTIANA BENTHAMIANA PLANTS TRANSFORMED WITH THE PLUM POX VIRUS HELICASE GENE ARE RESISTANT TO VIRUS-INFECTION

Nicotiana benthamiana Domin. plants were transformed with the cytoplas mic inclusion protein (CI) gene of plum pox potyvirus (PPV) to investi gate, whether this non-structural protein would be able to confer resi stance. The CI protein is an RNA helicase, which contains a conserved nucleotide binding motif (NTBM) and plays an important role in viral r eplication. Two gene constructions were developed for plant transforma tion. The first contains the original coding sequence of the CI gene u nder the control of 35S-promoter and nos terminator signal, the second is mutated in the NTBM region. Several transgenic plant lines were ob tained following Agrobacterium tumefaciens-mediated transformation. Th e integration of the viral genes into the plant genome was confirmed u sing the polymerase chain reaction and the transgene derived mRNAs wer e detected by Northern blot hybridization. The CI protein in the trans genic plants could not be detected by Western blot analyses. One trans genic line containing the mutated CI gene remained completely symptoml ess after PPV infection, indicating that the putative defective helica se gene was capable of eliciting virus resistance. (C) 1998 Elsevier S cience B.V. All rights reserved.