On the stability of sequences inserted into viral genomes

Willemsen, Anouk; Zwart, Mark P

Although few studies have addressed genomic stability of ssDNA viruses after an insertion, an example in wild viruses of frequent sequence insertions, duplications, and deletions are the Geminiviridae, with genomes of about 2.5-3 kbp (monopartite) or 4.8-5.6 kbp (bipartite). During the course of geminivirus infection in plants, shorter subgenomic DNAs often arise. These subgenomic DNAs can range in size and some result in defective DNAs (Stenger et al. 1992; Stanley et al. 1997; Patil et al. 2007) , that replicate at the expense of the full-length genome. These subgenomic DNAs can lead to reduced symptom severity in plants and thereby act as modulators of viral pathogenicity. It is speculated that the (sometimes stepwise) deletion process leading to subgenomic DNAs can also be the process leading to the reversion to wild-type full-length DNA molecules with either insertions or deletions that make these bigger or smaller than the wild-type genome (Martin et al. 2011 ).