Limitations on Geminivirus Genome Size Imposed by Plasmodesmata and Virus-Encoded Movement Protein: Insights into DNA Trafficking

R. L. Gilbertson
2003 The Plant Cell  
Animals and plants evolved systems to permit non-cell-autonomous trafficking of RNA, whereas DNA plays a cell-autonomous role. In plants, plasmodesmata serve as the conduit for this phenomenon, and viruses have evolved to use this pathway for the spread of infectious nucleic acids. In this study, a plant DNA virus was used to explore the constraints imposed on the movement of DNA through this endogenous RNA trafficking pathway. The combined properties of the geminivirusencoded movement protein
more » ... nd plasmodesmata were shown to impose a strict limitation on the size of the viral genome at the level of cell-to-cell movement. Size-increased viral genome components underwent homologous and nonhomologous recombination to overcome this strict limitation. Our results provide insights into the genetic mechanisms that underlie viral evolution and provide a likely explanation for why relatively few types of plant DNA viruses have evolved: they would have had to overcome the constraints imposed by an endogenous system operating to ensure that DNA acts in a cell-autonomous manner.
doi:10.1105/tpc.015057 pmid:14555695 pmcid:PMC280562 fatcat:63nwyindofgydgdrtpzj5qacem