Viroid Research
Viroids are the smallest known pathogens. They consist of circular closed RNA molecules and exclusively infect plants. Viroid genomes do not code for proteins. Replication, processing and systemic spreading of viroids is solely dependent on host enzymes. Similar to virus infections, the plant RNA interference mechanism [RNA interference (RNAi)] is activated upon viroid infections and viroid-specific short interfering RNAs (siRNAs) accumulate (Functional analysis of small regulatory RNAs). In contrast to most of the plant viruses, viroids do not encode RNAi or silencing suppressor proteins (Viral suppressors of RNAi). Thus, they must have developed an alternative strategy to escape the cytoplasmatic RNAi-mediated degradation of their genomes. Replication in the nucleus (Pospiviroidae) and chloroplasts (Avsunviroidae), respectively, may predominantly provide protection. However, to become systemic viroids need to move through the cytoplasm into neighboring cells. Due to the high degree of self-complementarity the viroid RNA can form a rod-like secondary structure (Fig. 1) which likely hampers the RNAi machinery to attack. In the frame of our viroid research projects we would not only like to diagnose viroid infestations but would also try to elucidate whether viroids have developed additional protection systems against RNAi. Finally, our work should help to develop viroid resistant plants
Figure 1: Secondary structure model of the PSTVd, CSVd und CbVd RNA.
Projects
Funding
Publications
Group members
Contact
<<<
Grapevine Biotechnology
Epigenetics
