Planetagarden
Viroids are single-stranded, covalently closed, circular, highly structured noncoding RNAs that cause disease in several economically important crop plants. They replicate autonomously and move systemically in host plants with the aid of the host machinery.
- What is a viroid disease?
- Which disease is caused by viroids in plants?
- How do Viroids infect plants?
- What diseases are caused by Viroids?
- What is an example of a viroid?
- Is viroid a virus?
- Which disease is caused by ustilago?
- What is the main difference between a viroid and a Virusoid?
- What is the structure of a viroid?
- Who discovered viroid?
- Where are Viroids found?
- What is the host for Viroids?
What is a viroid disease?
Viroids are the smallest known agents of infectious disease. Unlike viral nucleic acids, viroids are not encapsidated. Despite their small size, viroids replicate autonomously in cells of susceptible plant species.
Which disease is caused by viroids in plants?
When compared to diseases known to be caused by viruses, many viroid diseases appear to be relatively recent in origin — potato spindle tuber disease was first reported in 1922, chrysanthemum stunt disease in 1947, and cucumber pale fruit in 1974.
How do Viroids infect plants?
After replication, viroid progeny exit the nucleus or chloroplast and move to adjacent cells through plasmodesmata, and can travel systemically via the phloem to infect other cells. Viroids enter the pollen and ovule, from where they are transmitted to the seed. When the seed germinates, the new plant becomes infected.
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 is an example of a viroid?
Is viroid a virus?
Viroids are plant pathogens: small, single-stranded, circular RNA particles that are much simpler than a virus. They do not have a capsid or outer envelope, but, as with viruses, can reproduce only within a host cell. Viroids do not, however, manufacture any proteins. They produce only a single, specific RNA molecule.
Which disease is caused by ustilago?
Loose smut of barley is caused by Ustilago nuda. It is a disease that can destroy a large proportion of a barley crop. Loose smut replaces grain heads with smut, or masses of spores which infect the open flowers of healthy plants and grow into the seed, without showing any symptoms.
What is the main difference between a viroid and a Virusoid?
Viroids consist of small, naked ssRNAs that cause diseases in plants. Virusoids are ssRNAs that require other helper viruses to establish an infection.
What is the structure of a viroid?
Known viroids are single-stranded, covalently closed circular, as well as linear, RNA molecules with extensive regions of intramolecular complementarity; they exist in their native state as highly base-paired rods.
Who discovered viroid?
The pathogen is called a viroid by its discoverer, Dr. Theodor 0. Diener, to distinguish it from a virus.
Where are Viroids found?
Viroids are the smallest pathogenic agents yet described. They are single-stranded circular RNA molecules which vary in length from 246 to 463 nucleotides and are found only in plants.
What is the host for Viroids?
Viroids are restricted to higher plants and their hosts include monocots and dicots, herbaceous and woody plants, agronomic and ornamental plants. Viroids and viroid diseases are distributed globally, and their distribution may reflect exchange of infected germplasm and transmission through seeds [12].
