RNA-dependent RNA polymerase (RdRp) in the family Bromoviridae of positive-sense single-stranded RNA [(+)ssRNA] viruses
This group contains the RdRp of RNA viruses belonging to the family Bromoviridae, order Martellivirales. The Bromoviridae family of plant viruses contains tri-segmented, (+)ssRNA viruses with a total genome size of about 8 kb. There are six genera in this family: Alfamovirus, Anulavirus, Bromovirus, Cucumovirus, Ilarvirus, and Oleavirus. Bromoviridae virions are variable in morphology (spherical or bacilliform) and are transmitted mechanically, in/on the pollen and non-persistently by insect vectors. Members of the family cause major disease epidemics in fruit, vegetable and fodder crops such as tomato, cucurbits, bananas, and alfalfa. The RdRp domain displays a right hand with three functional subdomains, called fingers, palm, and thumb. All RdRps contain conserved polymerase motifs (A-G), located in the palm (A-E motifs) and finger (F-G) subdomains. All these motifs have been implicated in RdRp fidelity such as processes of correct incorporation and reorganization of nucleotides.
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