potato spindle tuber viroid discovery

In 1960s, potato spindle tuber was thought to be a viral disease. ... As a result, PSTVd was eradicated from Canada in late 1980s. Viroids similar to PSTVd (Pospiviroid) have been discovered and they are detected in symptomless ornamental plants.

Who discovered viroids?

The pathogen is called a viroid by its discoverer, Dr. Theodor 0. Diener, to distinguish it from a virus.

What was discovered by TO Diener?

Viroids displaced viruses as the smallest known infectious agents.
...
Theodor Otto Diener.

Theodor O. Diener
Known for	Discovery of viroids
Awards	National Medal of Science (1987)
Scientific career
Fields	Plant pathology

What causes potato spindle tuber disease?

Potato Spindle Tuber Viroid (PSTVd) is an EU listed quarantine pathogen of potatoes which causes stunting of the plant and malformation and cracking of tubers. The main host is potatoes but the disease also affects tomatoes and solanaceous ornamentals.

What is the genetic material of potato spindle tuber virus?

The Potato spindle tuber viroid ("PSTVd") was the first viroid to be identified. PSTVd is a small, single stranded circular RNA molecule closely related to the chrysanthemum stunt viroid.

Which plant virus is Gemini virus?

Geminiviruses (family Geminiviridae) are small single-stranded (ss) DNA viruses infecting plants. Their virion morphology is unique in the known viral world – two incomplete T = 1 icosahedra are joined together to form twinned particles. Geminiviruses utilize a rolling-circle mode to replicate their genomes.

Can Viroids infect humans?

Viroids do not have a capsid or outer envelope and can reproduce only within a host cell. Viroids are not known to cause any human diseases, but they are responsible for crop failures and the loss of millions of dollars in agricultural revenue each year.

Which disease is 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.

Who discovered free infectious DNA?

Complete Step by Step Answer: Theodor Otto Diener was a Swiss- American Plant pathologist who discovered small self- replicating particles which lacked protein coats and had infectious free RNA particles. He named these microorganisms as Viroid which meant L. virus- poison, eidos- diminutive.

What is the meaning of 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 are absent in Viroids?

Absence of protein coat in viroid but present in virus. Presence of low molecular weight RNA in virus but absent in viroid. ... c.

Are Virusoids self replicating?

A second type of pathogenic RNA that can infect commercially important agricultural crops are the virusoids, which are subviral particles best described as non–self-replicating ssRNAs. The virusoid genomes are small, only 220 to 388 nucleotides long. ...

Which of the following are present in infectious agent discovered by to diner?

Thus, the correct answer is 'Viroids.

How many virus particles are in Geminiviridae?

There are currently 485 species in this family, divided among 9 genera.
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Geminiviridae
Purified Maize streak virus (MSV) particles stained with uranyl acetate. Size bar indicates 50 nm.
Virus classification
(unranked):	Virus

Are viruses viroids and prions living?

They can therefore be regarded as living - and virology is indeed a branch of biology. " My understanding is that viruses and viroids (not mentioning prions) are non-living since they are metabolically inactive and unable to reproduce outside a host.

What is difference between virion and viroid?

A virion is the infectious particle that is designed for transmitting the nucleic acid genome among hosts or host cells. ... Nucleic acid can be DNA or RNA. Viroid is formed only of RNA. A protein covering of coat is present.

What is the difference between a virus and a virion?

The main difference between virus and virion is that virus is the nucleoprotein particle whereas virion is the active, infectious form of the virus. A virus consists of genetic material covered by a protein capsid.

Are prions living?

Prions, however, are not living organisms. Prions are infectious proteins. For unknown reasons, these proteins refold abnormally and cause a domino effect in surrounding proteins which in turn mutate into stable structures. Prions will then cause tissue damage and cell death to surrounding areas.

What is smaller than a virus?

There are things out there even smaller than viruses. The two that scientists have discovered are called prions and viroids. A prion is (as far as we know) just a protein. Prions are proteins that can invade cells and somehow direct their own duplication, making more of the isolated proteins.

What does prion mean?

The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain. The functions of these normal prion proteins are still not completely understood.

Which of the following statements is wrong for viruses?

They have ability to synthesize nucleic acids by replication. Antibiotics do not acts against virus as they are made up of polymorphic protein coat. Viruses have different type of symmetry like icosahedral and helical. So, the correct answer is option B.

Who discovered bacteriophage?

Bacteriophage (bacterial viruses) were discovered independently by two scientists, Frederick Twort and Felix d'Herelle, in 1915 and 1917. D'Herelle went on to carry out an in-depth study of these viruses, including replication and adaptation, and he proposed their possible use in anti-bacterial treatment.