RNA-dependent RNA polymerase (RdRp) in the genus Betanecrosvirus of positive-sense single-stranded RNA [(+)ssRNA] viruses, within the Procedovirinae subfamily
This group contains the RdRp of RNA viruses belonging to the Betanecrosvirus genus within the subfamily Procedovirinae, family Tombusviridae, order Tolivirales. In the Betanecrosvirus genus plants serve as natural hosts, and transmission routes are mechanical, seed borne, and by contact. There are three species in this genus: Beet black scorch virus, Leek white stripe virus, and Tobacco necrosis virus D. Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription, using the premature termination model of subgenomic RNA transcription is the method of transcription. The virus exits the host cell by tubule-guided viral movement. 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",