Plum Pox Potyvirus (PPV) is the causal agent of Sharka disease in stone fruits (Prunus). Since the 60s, this disease spreads in German plum and prune growing areas and has become the most important viral disease in stone fruits. Due to the efficient aphid transmission of the virus, all major growing areas are severely infested. The disease leads to a significant reduction in the quality of the fruit in most varieties and to a reduction in the yield and growth of the tree. We investigated the genetic variability of PPV strains in Germany and were able to detect PPV-M and PPV-Rec strains in southwestern German stone fruit growing areas for the first time. These are more virulent than the widespread PPV-D strains.
Fig. Sharka on apricot
Fig. Sharka on plum
One focus in the work area "fruit diseases" is the development of rootstocks that are resistant to the apple proliferation. Natural resistance was found in Malus sieboldii and its offspring. However, these partially show a hypersensitive reaction to latent apple viruses (Apple stem grooving virus, Apple stem pitting virus, Apple chlorotic leaf spot virus). We molecularly characterized the involved apple virus isolates. Through targeted and standardized inoculation experiments in the in vitro system, the symptom expression of selected isolates was investigated individually, in combination as well as with and without phytoplasmas.