Viroid

On the last article about viruses always says about viroids that is resulted from viruses. After the viruses contaminated the plant and other hospes, viruses that create a viroid that causes the hospes will suffer from viruses.

Viroids are extremely small infections particles that are thus far known to cause diseases only in higher plants, including the potato, tomato, and chrysanthemum. They consist solely of RNA and are about 1/1000 the size of the smallest known virus. Viroids can cause stunting of overall plant growth, distortions of leaf shape, discoloration of leaves, or even death of the entire plant.

Viroids can be transmitted between plant generations through both pollen and ovules. They can also be transmitted from an infected to a noninfected plant by farm implements. Their mode of reproduction in host cells, however, has not yet been determined, nor has any protein been found in host cells that could be associated with a particular viroid. It is thought that viroids represent segment of normal cellular RNA that somehow have become transmissible, disrupting the host’s metabolism.