Double Stranded RNA in Viruses

Introduction:
RNA or ribonucleic acid is a nucleic acid that plays an essential role in protein synthesis, gene expression, and cellular regulation. RNA can be single-stranded or double-stranded. Double-stranded RNA (dsRNA) viruses can infect animals, plants, and bacteria. The dsRNA genome of these viruses is unique and distinct from other RNA viruses.

Cauliflower Mosaic Virus:
The Cauliflower Mosaic Virus (CaMV) is a plant virus that has a double-stranded RNA genome. CaMV is a member of the Caulimoviridae family and infects a wide range of plant species. The virus has a polyhedral capsid that encapsidates the dsRNA genome. The genome codes for seven open reading frames (ORFs) that are involved in the replication, transcription, and movement of the virus.

TMV:
Tobacco mosaic virus (TMV) is a plant virus that has a single-stranded RNA genome. TMV is a rod-shaped virus that is composed of a helical capsid protein. The RNA genome of TMV is not double-stranded.

Fi × 174:
F1 × 174 is a bacterial virus that has a single-stranded DNA genome. The virus is composed of a protein coat that encapsidates the viral genome. The genome codes for 11 proteins that are involved in the replication, transcription, and assembly of the virus.

Reovirus:
Reovirus is a double-stranded RNA virus that infects mammals, birds, and reptiles. The virus has a segmented genome that codes for 11 proteins. Reovirus is a member of the Reoviridae family and is composed of a double-layered protein capsid that encapsidates the dsRNA genome.

Conclusion:
In conclusion, only two of the viruses listed above have a double-stranded RNA genome, which are Cauliflower Mosaic Virus and Reovirus. TMV has a single-stranded RNA genome, and Fi × 174 has a single-stranded DNA genome. Understanding the genome of viruses is essential for developing effective antiviral therapies and vaccines.

Reoviridae are currently classified into nine genera. The genomes of these viruses consist of 10 to 12 segments of dsRNA, each generally encoding one protein.
so correct answer is '4'.