Genome Packaging in Plant Viruses

Viruses are the amazing particles in nature that is designed to reproduce with a minimal genetic set. This vital process is very complex and requires the time and coordinated activities of a number of virus and host proteins. In order to the genome packaging, the virus protein subunits interact with each other and with viral nucleic acids. The general principle in packaging is the interaction between the structure of coat protein and a specific signal in RNA. Replication of +ssRNA viruses and their nucleocapsid assembly occurs in the cytoplasm and requires Pro-Pro and Pro-RNA interactions. The packaging process in them is spontaneous and does not require ATP. The interaction between the coat protein subunits and the genomic RNA is controlled by a unique structure in the sequence that is highly desired to interaction with the coat protein. The presence of these unique structures in the viral nucleic acid, called the packaging signal or OAS (origin of assembly sequence), causes viral nucleic acid to be distinguished from other cellular RNA molecules in the region which assembly takes place. General knowledge of the precise mechanisms of viruses, the configuration and aggregation of viruses, and the packing of their genomes that lead to the formation of stable viral structures is an important prerequisite for understanding the overall biology of viruses.