Viroids

Definition

Viroids are small, circular RNA molecules that infect plants and can cause various diseases. Unlike viruses, they lack a protein coat and do not code for proteins.

5 Must Know Facts For Your Next Test

1. Viroids are the smallest known infectious pathogens, consisting solely of a short strand of circular RNA.
2. They do not encode any proteins and rely entirely on host cellular machinery for replication.
3. Viroids primarily infect plants, causing diseases such as potato spindle tuber and citrus exocortis.
4. The replication of viroids occurs in the nucleus or chloroplasts of the host plant cells.
5. Transmission of viroids can occur through mechanical means, insect vectors, or vegetative propagation.

Review Questions

Related terms

Virusoids: Subviral agents similar to viroids but require a helper virus for replication.

Prions:

Infectious proteins that cause neurodegenerative diseases in animals by inducing abnormal folding of specific proteins.

Viruses:

Acellular pathogens consisting of nucleic acid enclosed in a protein coat that infect living organisms.