Question

Potato spindle tuber disease-causing organism is different from HIV as the former
a) contains RNA
b) Has no capsid
c) has no proteins
d) all of the above

Answer 1

Hint: Potato spindle tuber disease is caused by a viroid which causes lowering the growth of the plants and the potato it bears. The potato spindle tuber viroid was the first viroid to be discovered. It is a small and single-stranded closed RNA containing viroid.

Complete answer:
The potato spindle tuber disease is caused by the potato spindle tuber viroid. This viroid has the presence of single-stranded closed RNA. This RNA only codes for particular proteins and has an absence of capsid and other proteins. This viroid only infects the potato plants and doesn’t affect the humans. HIV is a retrovirus that infects humans mostly. It has the presence of RNA but also has the presence of a protein coat and capsid. Viroids were discovered by Theodor Otto Diener who was a plant pathologist. They were discovered and named by the same scientist in the year 1971. The first viroid which was discovered was of the potato spindle tuber viroid (PSTVd). The viroid’s replicated by the enzyme RNA polymerase II. They are different from the viruses as they have an absence of a protein coat. The mature viroids are able to infect plants and cause diseases in them.

So, the answer is ‘all of the above’.

Note: Viroids are the smallest pathogens known to humans. They only infect the plant and cause diseases in them. They are not found to be infectious in humans or animals. They have single-stranded RNA and have an absence of the protein coat on them. They do not encode for any protein but are able to replicate when introduced into host plant varieties.