Selection for a specific tobacco mosaic virus variant during bolting of Nicotiana sylvestris

Abstract

In an isolate of tobacco mosaic virus, TMV U1, a small subpopulation of virus that invokes the hypersensitive reaction on Nicotiana sylvestris Spegaz. & Comes exists and is strongly selected for during replication in plants that are undergoing development of shoot axes during bolting. Virus of this phenotype (NL) can infect and move systemically in rapidly developing parts of N. sylvestris plants and is strongly selected for in upper tissues of the plants only during the development of the shoot axis. This selection results in a dramatic change in the genetic composition of the virus population in the upper part of the plant. No accumulation of NL-type virus occurred when N. sylvestris plants were inoculated with TMV204, a clonal population derived from RNA transcripts of a plasmid carrying a cDNA copy of the TMV genome.