Development of a non-radioactive dot-blot hybridisation assay for the detection of Pelargonium flower break virus and Pelargonium line pattern virus

The ornamental geranium, Pelargonium x hortorum Bailey, is a traditional ornamental plant widely cultivated in Europe and Northern America. Vegetative propagation facilitates rapid spread of viral infections which have detrimental effects on the production and the quality of the crop. A non-radioactive nucleic acid hybridisation method was developed for detection of Pelargonium flower break virus (PFBV) and Pelargonium line pattern virus (PLPV) in infected host plants. This method was significantly more sensitive than the conventional ELISA test when using either purified viral preparations or crude plant extracts. The distribution of the viruses was studied by means of the non-isotopic hybridisation technique. The results indicated that the petioles and the apical blade regions of fully expanded leaves were the best source of test material. The hybridisation procedure enables the detection of PFBV and PLPV in a single assay, and its simplicity allows its application to routine large-scale indexing.