Molecular Characterisation of the Ribgrass Mosaic Virus - Impatiens

Summary

Several molecular characteristics of the Ribgrass mosaic virus - Impatiens (RMV-Imp) were investigated in this thesis including the evaluation of three mutation constructs in virulence and virus accumulation on Nicotiana (N.) benthamiana and N. tabacum. Regarding a strategy of expressing foreign genes in plants, two diverged RMV-based expression vectors containing a green fluorescent protein were cloned into the binary vector pPZP200 for subsequent agroinfiltration work. An infectious full-length clone of RMV and three RMV-based mutants already existed. They vary depending on which of the two putative ORFs is inactivated. An additional mutation site of one of these mutation constructs was discovered and reverse mutated. After the inoculation of the constructs on N. benthamiana and N. tabacum, the analysis revealed distinct effects in virus accumulation and symptom characteristics of the three mutation constructs. These results differ from the ones of the wild type clone. Accordingly, all three mutants show both lower virus accumulation levels and lesser symptom characteristics. Further, the results from N. benthamiana indicate an ability to reverse mutate the -4K virus. In addition to the description and the analysis of these results, the potential role of the two putative ORFs will be discussed and an outlook on further investigations will be given.