A Viroid is an infectious molecule, which consists of a zirkul¤ren relatively short (150-400 nucleotides)
To a certain extent "a reduced "virus concerns. To the Viroid above all the protein covering of a normal Virus.Viroide is missing comes in nature as pathogen of plants forwards (Pflanzenpathogen).
The RNA of the Viroide contains many complementary ranges, whereby linear structures are formed. Thus approx. 50 Nm long rod-shaped structures could be observed in electron microscopic investigations.
Most Viroide emerges in culture planting and/or is there common at most. A good example is the Kartoffelspindelknollen Viroid Potato spindles Tuber Viroid (Abk. PSTVd), which strikes potatoes, tomatoes and many other plant types and causes large economic damage.
Contrary to viruses Viroide do not carry genes. They code thus no proteins, why Viroide are dependent with their Replikation exclusively on enzymes of the plant hosts. The infection mechanism of the Viroide is so far unclear. However nucleotide sequences were found in the plant host DNA, which are complementary to the sequences of the Viroide.
Even if Viroide differ among themselves strongly, they can be arranged nevertheless in some classes; here are to call those
and many further