---

The book contains abstracts of talks and posters presented by participants of the "International Conference on Viroids and Viroid-Like RNAs". The conference was held on June 25-28, 2015, in Ceské Budejovice, Czech Republic. Viroids are the smallest infectious particles known: they consist of a single non-coding circular RNA molecule, ranging in size from about 250 to 400 nucleotides. They function as a minimal parasite replicating autonomously in the plant host´s cells and promoting specific diseases leading to significant losses in the yield of some important crops. The abstracts focus on three important aspects of viroid research: viroid secondary and tertiary structure and structural dynamics, which are critical for their replication cycle exploiting the host machinery; transcriptional and post-transcriptional gene silencing induced by viroids, which is thought to be leading to host´s symptoms; and viroid outbreaks as threats to crops and ornamental plants.

---