What diseases are caused by viroids?
The only human disease known to be caused by a viroid is hepatitis D. This disease was previously ascribed to a defective virus called the delta agent. However, it now is known that the delta agent is a viroid enclosed in a hepatitis B virus capsid.
What do you mean by viroids?
viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases. The particle consists only of an extremely small circular RNA (ribonucleic acid) molecule, lacking the protein coat of a virus. Whether viroids occur in animal cells is still uncertain.
What is the difference between a virus and a viroid?
Viruses (Virus particles or virions) are usually units consisting of nucleic acids and coat proteins called capsids. Viroids consist only of RNA, i.e. they contain no protein at all.
Who discovered viroids?
Dr. Theodor 0. Diener
The pathogen is called a viroid by its discoverer, Dr. Theodor 0. Diener, to distinguish it from a virus.
How do you treat viroids?
Current effective control methods for viroid diseases include detection and eradication, and cultural controls. In addition, heat or cold therapy combined with meristem tip culture has been shown to be effective for elimination of viroids for some viroid–host combinations.
How do you detect viroids?
As stated earlier, viroids can be detected by biological indexing (bioassay) of the suspect plant materials on a range of indicator hosts. Indicator hosts express diagnostic symptoms when infected by specific pathogens (Fig. 3).
What is the genetic material of viroids?
Like some viruses, viroids are little more than a strand of genetic material called ribonucleic acid (RNA). Unlike most viral RNAs, viroids can’t make proteins, nor do they wear a protective protein shell to avoid being torn apart by a host plant’s powerful enzymes.
What do viroids do?
Viroids are minimal RNA replicons composed by a single-stranded and highly structured circular small RNA able to infect plants and induce diseases. Viroids lack protein-coding capacity and are therefore parasites of their host transcription machinery.
Which disease is caused by viroids in plants?
The diseases that are caused by viroids in plants are citrus exocortis, cucumber pale fruit, chrysanthemum stunt, etc.