Question

Cauliflower mosaic virus contains
(a) ssRNA
(b) dsRNA
(c) dsDNA
(d) ssDNA

Answer 1

Hint: The genetic material of cauliflower mosaic virus is similar to the genetic material in humans. CaMV infects mostly plants of the Brassicaceae family but some CaMV strains also are ready to infect Solanaceae species of the genera Datura and Nicotiana.

Complete step by step answer:
CaMV contains a circular double-stranded DNA molecule. Cauliflower mosaic virus (CaMV) is the species of the family Caulimoviridae. Cauliflower mosaic virus (CaMV) may be a member of the genus Caulimovirus, one among the six genera within the Caulimoviridae family, which are pararetroviruses that infect plants and replicate through reverse transcription a bit like retroviruses, but the viral particles contain DNA.

Additional information:
- The first virus was shown to possess a DNA genome and therefore the first shown to duplicate by reverse transcription.
- The virus is a crucial source of gene regulatory elements, used exclusively within the genetic manipulation of plants.
- CaMV affects plant development, especially in early infections when also the inflorescence is prevented.
- The Cauliflower mosaic virus promoter (CaMV 35S) is employed in most transgenic crops to activate foreign genes which are artificially inserted into the host plant.
- The promoter of the 35S RNA may be a very strong constitutive promoter liable for the transcription of the entire CaMV genome. It is documented for its use in plant transformation.
- The mechanism of expression of those proteins is exclusive, therefore the ORF VI protein controls translation reinitiation of major open reading frames on the polycistronic 35S RNA, a process that normally only happens on bacterial mRNAs.
- CaMV does not contain any non- coding region wherein foreign DNA can be inserted but there are two genes namely gene II and gene VII have no essential functions for the virus, therefore, the genes of interest are often replaced within the place of those two genes.
- It is the promoter of choice for plant gene- splicing, because it may be a strong and constitutive promoter.
- Symptoms like a mosaic, necrotic lesions, stunted growth, deformation of the general plant structures.
- CaMV is transmitted during a non- circulatory manner by aphid species Mysus.
So, the correct answer is, ‘dsDNA.’

Note:
- Caulimovirus contains circular ds DNA and is spherical in shape.
- This group includes 15 viruses of which CaMV is the most vital for gene transfer.
- The other caliciviruses include carnation etched virus, dahlia mosaic virus mirabilis mosaic virus and strawberry vein banding virus.