What is the Difference Between Viroid and Virusoid?

Viroids and virusoids are both single-stranded, circular RNA molecules that lack a protein capsid, but they differ in certain aspects:

1. Replication: Viroids are pathogens of higher plants and replicate autonomously in the host cell, while virusoids require a "helper" virus to establish an infection.
2. Location: Viroid replication takes place in the nucleus of the host, while virusoid replication occurs in the cytoplasm of the host cell.
3. Encapsidation: Viroids are not encapsidated, whereas virusoids are encapsidated by their helper virus coat proteins.
4. Size: Viroids are smaller than virusoids, typically consisting of 240 to 400 nucleotides, while virusoids are larger.

In summary, the key difference between viroids and virusoids is that viroids can replicate autonomously in the host cell, while virusoids require a helper virus to establish an infection.

Comparative Table: Viroid vs Virusoid

Here is a table comparing the differences between viroids and virusoids:

Viroids are small, infectious RNA particles that cause diseases in plants. They consists of single-stranded circular RNA and do not possess a protein coat. Viroids do not require a helper virus to establish an infection.

Virusoids are subviral particles that are non-self-replicating single-stranded RNAs. They require the presence of a specific "helper" virus to establish an infection. There are only five described types of virusoids and their associated helper viruses, all from the family of Sobemoviruses.