Video by Scishow: Viroids: Possibly the Smallest Pathogens on Earth:
Potato spindle tuber disease wasn't a life-or-death situation, but it led to the discovery of viroids: infectious, replicating bits of RNA
Hosted by: Michael Aranda

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Video by Scishow: Viroids: Possibly the Smallest Pathogens on Earth:
Potato spindle tuber disease wasn't a life-or-death situation, but it led to the discovery of viroids: infectious, replicating bits of RNA
Hosted by: Michael Aranda
Viroids
Patreon | Ko-fi
Hop Stunt Viroid
Recently I learned about viroids. A viroid is basically a short strand of circular, single-stranded RNA, about 100 times smaller than a virus.
The hop stunt viroid is a quite common hop disease in the hop garden of Washington and can lead to slow or no plant growth.
Read more: https://en.wikipedia.org/wiki/Viroid
Watch more: https://www.youtube.com/watch?v=fhYbQHP44-c
Potato spindle tuber disease wasn't a life-or-death situation, but it led to the discovery of viroids: infectious, replicating bits of RNA.
Viroids are the smallest infectious pathogens known. They are solely composed of a short strand of circular, single-stranded, RNA without protein coat. All known viroids are inhabitants of higher plants, in which most cause diseases, some of which are of slight to catastrophic economic importance.
[Above:] The reproduction mechanism of a typical viroid. Leaf contact transmits the viroid. The viroid enters the cell via its plasmodesmata. RNA polymerase II catalyzes rolling-circle synthesis of new viroids.
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Scientists have discovered mysterious virus-like ‘obelisks’ in the human gut and mouth. These tiny structures fall into the viroid class and
We may have an adequate understanding of the human body in that, well, we invented aspirin and sequenced the genome, but researchers still find out new things about the humble homo sapien all of the time. Case in point? Scientists just discovered a previously unknown entity hanging out in the human gut and mouth. The researchers are calling these virus-like structures “obelisks”, due to their presumed microscopic shape. These entities replicate like viruses, but are much smaller and simpler. Due to the minuscule size, they fall into the “viroid” class, which are typically single-stranded RNAs without a protein shell. However, most viroids are infectious agents that cause disease and it doesn’t look like that’s the case with these lil obelisks, as reported by Live Science. So why are they inside of us and what do they do? That’s the big question. The discoverers at Stanford University, the University of Toronto and the Technical University of Valencia have some theories. They may influence gene activity within the human microbiome, though they also hang out in the mouth. To that end, they have been found using the common mouth-based bacterium Streptococcus sanguinis as a host. It’s been suggested that these viroids infect various bacteria in both the mouth and gut, though we don’t know why.
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Some acellular organisms like virus, viroids and lichens cannot find their place in five kingdom classification.
Viruses are non cellular organisms and act as a connecting link between plants and animals. Lichens are symbiotic association between algae and fungi. Viroids are infectious agents that are smaller than virus.